G Kenyon
Technology
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decision for WorkSafe
New Zealand
under the Official Information Act 1987
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G Kenyon Technology Ltd
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Date:  07 March 2026
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t:  +44 (0) 753 985 1252
Author:  Graham Kenyon
United Kingdom.
w:  www.gkenyontech.com
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Purpose:  Information
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G Kenyon
Review of technical decision for WorkSafe New Zealand
Technology
Amendment Record
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Graham Kenyon

1987

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Executive Summary
This report documents a review by an independent expert of the technical decision taken to list
the deletion of Clauses 2.3.2.1.2 (b) and (c) from AS/NZS 3000:2018 (including Amendments 1, 2
and 3) in Schedule 2 to the New Zealand Electricity (Safety) Amendment Regulations 2025. The
report concludes that the decision is justified, but that there are residual risks. Some of the
residual risks are already mitigated by existing practices, standards and guidance, whilst others
require additional industry guidance and/or standards to be implemented.

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Figures & Tables
Figure C.1 Example of path of possible diverted neutral currents ........................................... 28
Figure F.1 Figure 8 from IEC 60669-1:2017 ............................................................................ 38

Table 2.1 Potential risks associated with the removal of Clauses 2.3.2.1.2 (b) and (c) from
AS/NZS 3000:2018 ................................................................................................................. 9
Table 3.1 Potential mitigation already in place of risks associated with the removal of Clauses
2.3.2.1.2 (b) and (c) from AS/NZS 3000:2018 ......................................................................... 15

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1  Introduction
1.1  Formal details
1.1.1  This report has been prepared by Graham Harry Kenyon, Managing Director and Principal
Consultant of G Kenyon Technology Ltd, 15, Westmorland Ave, Thornton-Cleveleys,
Lancashire, FY5 2LX, United Kingdom.
1.1.2  I am a Chartered Engineer, Member of the Institution of Engineering and Technology, a
registered  European Engineer through Engineers Europe (formerly FEANI),  and a
Technical Member of the Institute of Occupational Safety and Health. My career history
and experience exceeds 30 years. I practise as an independent international electrical
engineering consultant with relevant experience in electrical installations, and electrical
1987
product assurance and safety. I have been in my current position for 10 years 10 months.
my  previous  experience was engineering and technical assurance, for projects
developing and implementing specialist systems for major infrastructure programmes. I
Act
have been actively involved with standardization in the electrotechnical sector for around
20  years, and have held formal qualifications in UK electrical installation design,
installation and verification practice since 1992. I am the current Chair of joint IET/BSI
Committee JPEL/64, which is the UK national committee responsible for a number of
standards including BS 7671 Requirements for Electrical Installations (IET Wiring
Regulations, 18th Edition), and the international IEC 60364 series, and also the current
Chair of UK technical committee GEL/600 responsible for BS 7430 Code of Practice for
Earthing. I am the author of an extensive range of electrotechnical industry guidance and
training publications  for the  UK;  a comprehensive list can be found at:
Information
https://www.gkenyontech.com/the-principal/publications/.
1.1.3  I have been engaged by WorkSafe New Zealand to conduct a technical review, which is
outlined in the background to this report (Section 1.2).

Official
1.2  Background
1.2.1  Schedule 2 to the  New Zealand  Electricity  (Safety)  Amendment Regulations 2025
the
[reference 1]  deletes Clauses 2.3.2.1.2 (b) and (c) from AS/NZS 3000:2018 (including
Amendments 1, 2 and 3) [reference 2].
1.2.2  The provisions of Clauses 2.3.2.1.2 (b) and (c) from AS/NZS 3000:2018 (including
Amendments 1, 2 and 3) [reference 2] relate to conditional requirements for switching
neutral conductors in electrical installations, and   requirements to limit  switching  of
under
protective earthing conductors and combined protective earth and neutral (PEN)
conductors.  Specific provisions of these Clauses are examined in Appendix C  to  this
Report.
1.2.3  The intent of deleting Clauses 2.3.2.1.2 (b) and (c) from AS/NZS 3000:2018 (including
Amendments 1, 2 and 3) [reference 2] for New Zealand was to ‘future proof’ the New
Zealand  Electricity (Safety) Amendment  Regulations  2025 [reference 1], to facilitate:

Released
(a)  Improvements in the integrity of electricity supplies to homes as a result of power
outages in the distribution network, by allowing switching arrangements to ‘island’
the installation to operate from a source of energy independent from the public
distribution network  (for example, temporary generators or renewable energy
systems with battery storage); and

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Review of technical decision for WorkSafe New Zealand
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(b)  The future use of protective devices that can operate to disconnect electric vehicles
from all live conductors, and the protective earthing system, in the event of detection
of conditions indicative of a broken PEN conductor upstream of the supply to the
electric vehicle charging equipment. The Institution of Engineering and Technology
(IET) in the UK published a standard for such devices, IET 01:2024 [reference 3].
1.2.4  WorkSafe New Zealand have received correspondence from the New Zealand Electrical
Inspectors Association, which has been reviewed by myself after I formed an
independent opinion.

1987
1.3  Use of this report
1.3.1  Subsequent Sections of this report are intended to be considered as fol ows: Act
(a)  Section 2 of the report summarizes the risks to be considered in achieving the aims.

(b)  Section 3 of the report considers the residual risks that exist at the time of writing
the report and provides a commentary on whether they are mitigated with provisions
outside AS/NZS 3000 [reference 2] at the time of writing this report. It also provides a
commentary on residual risk, and recommendations to address those risks.

(c)  Section 4 of this report summarizes an overall conclusion of the review.
Information

1.3.2  Appendices C to F inclusive provide further detail, referenced in Sections 2 t o 4 inclusive,
to provide technical background. In particular:
(a)  Appendix C provides facts associated with the risks discussed in Section 2.

Official
(b)  Appendices D and E provide comparative provisions in BS 7671 and IEC 60364, as
referenced in Sections 2 to 4and Appendix C.
the

(c)  Appendix F provides a commentary on the timing of switching of the neutral
conductor in relevant product standards, as referenced in Sections 2 to 4 and
Appendix C.
under
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Technology
2  Risks to be considered
2.1  Introduction
2.1.1  This Section of the report summarises the risks to be considered in relation to the removal
of  Clauses 2.3.2.1.2 (b) and (c) from AS/NZS 3000:2018  [reference 2], and the
development of subsequent industry guidance and standards as listed in Table 2.1.
Table 2.1 Potential risks associated with the removal of Clauses 2.3.2.1.2 (b) and (c) from
AS/NZS 3000:2018
Ref  Removal of
Potential
Cause
For hazard
provision in
hazard
detail, see
1987
AS/NZS 3000
Paragraph
1
2.3.2.1.2 (b)(i)
Electric
• Hazardous touch-voltages between
2.4.1 and 2.4.2,
and
shock
simultaneously accessible exposed-
and Appendix C
Act
2.3.2.1.2 (c)
conductive-parts connected to
Paragraphs C3-2,
different earthing systems (IEC 60364- C3-3, C3-6, C3-7,
4-41, Clause 411.3.1.1)
C3-8, C3-9, C7-2
2
2.3.2.1.2 (b)(i)
Electric
• Change of earthing resistances in
2.4.3 and
and
shock
‘global earthing’ system.
Appendix C
2.3.2.1.2 (c)
• Hazardous touch-voltages between
Paragraphs C3-4,
simultaneously accessible exposed-
C7-2
conductive-parts connected to
different earthing systems (IEC 60364-
4-41, Clause 411.3.1.1)
Information
3
2.3.2.1.2 (b)(i)
Electric
• Diverted neutral currents from
2.7.1 and 2.7.2,
NOTE: guidance
shock (of
islanded installation to distributor
and Appendix C
for island
those
MEN if this is not switched (and PEN
Paragraphs  C6-1
switching in
working on
conductors are not precluded in
to C6-5 inclusive
development
MEN
islanded installations)
network)
4
2.3.2.1.2 (b)
Electric
• Failure to disconnect live conductors
2.5.1 and 2.5.2
Official
shock during
on operation of devices that ought to
and Appendix C
maintenance
provide safe disconnection/isolation
Sections C3 and
C4
the
5
2.3.2.1.2 (b)(ii),  Damage to
• Disconnected neutral in a three-
2.5.1 and 2.5.2
2.3.2.1.2 (b)(ii )  equipment
phase system or circuit when active
and Appendix C
and 2.3.2.1.2
(line) conductors remain connected
Sections C3 and
(b)(iv)
C4
6
2.3.2.1.2 (b)(ii),  Fire/burns
• Disconnected neutral in a three-
2.5.1 and 2.5.2
2.3.2.1.2 (b)(ii )
under  phase system or circuit when active  and Appendix C
and 2.3.2.1.2
(line) conductors remain connected.
Sections C3 and
(b)(iv)
C4
7
2.3.2.1.2 (c)
Electric
• Disconnected protective conductor
2.6.1 and 2.6.2
shock
and high protective conductor
and Appendix C
currents
Paragraph C5-3
8
2.3.2.1.2 (c)
Electric
• Disconnected protective conductor
2.6.1 and 2.6.2
shock
and electrical fault that would
and Appendix C
normally conclude with automatic
Paragraphs C5-4,
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disconnection of supply
C5-5
NOTE 1:  In Table 2.1 electric shock general y means physiological harm, or death, from electric shock. Secondary
effects of injury resulting from involuntary reactions due to contact with electricity, are not precluded.
NOTE 2:  The term ‘global earthing system’ is defined in Clause 3.7.19 of IEC 61936-1. See Appendix B. In the context
of this report, the safety advantages of multiple earth connections in the MEN system, and via connected
installations and their extraneous-conductive-parts, is intended.
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2.2  Clause 2.3.2.1.2 of AS/NZS 3000:2018 [reference 2]
2.2.1  Clause 2.3.2.1.2 of AS/NZS 3000:2018 [reference 2] concerns requirements for:
(a)  provision of a device for isolating active conductors in AC circuits;
(b)  preclusion of switching MEN and PEN conductors;
(c)  conditions under which neutral conductors (other than MEN and PEN conductors)
should be switched; and
(d)  preclusion of switching protective (earthing) conductors.
2.2.2  There are risks associated with switching of neutral, earthing (protective) conductors and
PEN conductors which Clause 2.3.2.1.2  of AS/NZS 3000:2018 [reference 2]  aims to
1987
address.
2.2.3  Facts pertaining to Clause 2.3.2.1.2 of AS/NZS 3000:2018 [reference 2] are detailed in
Section C1 of Appendix C to this report.
Act
2.3  Reasons for deletion of 2.3.2.1.2 (b) and (c) of AS/NZS 3000:2018
[reference 2]
2.3.1  Switching for alternative sources of energy to improve resilience of electricity
supplies
2.3.1.1  In order to facilitate switching arrangements to improve resilience of electricity supplies
to homes, it will be necessary to implement switching arrangements  (for example
supply transfer arrangements and/or island mode switching arrangements).
Information
2.3.1.2  Switching between the MEN system and alternative sources of energy  will involve
switching active conductors, along with neutral and protective conductors.
2.3.1.3  Existing guidance for connection of temporary generation  (WorkSafe New Zealand
Technical Bulletin Connecting a generator to the wiring of a house or building following
an emergency [reference 4]) involves the manual disconnection of the MEN conductor
Official
at the installation, along with ensuring the neutral of the installation is connected to an
earth electrode as a means of earthing.
2.3.1.4  If the existing guidance (WorkSafe New Zealand Technical Bulletin Connecting a
the
generator to the wiring of a house or building following an emergency [reference 4]) were
to be translated directly to guidance for switching, this would necessitate switching of
the MEN conductor, and along with neutral and protective conductors  for the
alternative form of energy.
under
2.3.1.5  Facts associated with this type of switching arrangement are provided in Appendix C to
this report, Paragraphs C2-1 to C2-6 inclusive and Section C7.
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2.3.2  Improvements in protection of electric vehicle charging instal ations
2.3.2.1  In order to facilitate the use of open-PEN detection devices (OPDDs), for example to
IET 01:2024 [reference 3] (see NOTE to this Paragraph), it is necessary to not preclude
the switching of earthing (protective) conductors. OPDDs operate to disconnect all live
conductors (active and neutral) along with the protective conductor, to facilitate a
situation similar to removing a plug from a socket-outlet. It is necessary to disconnect
the earthing (protective) conductor, because it is that conductor which transfers the
MEN neutral potential rise to the exposed-conductive-parts of a vehicle during an open
PEN fault in the MEN network.
NOTE:  At the time of writing this report, the only  product standard for OPDDs is
1987
IET 01:2024  [reference 3].  It is not a UK  national standard, but an industry
standard published by the Institution of Engineering and Technology (IET),
developed with industry participation and public consultation. The provisions
Act
of Regulation 722.411.4.1 of BS 7671 refer to to other provisions in BS 7671 that
address the conditions under which the protective conductor can be switched;
however, there are not adequate provisions in BS 7671 to facilitate a product
standard.  Examples of the missing provisions in BS 7671 include  those for
classification, marking, durability and verification.+
2.3.2.2  Facts associated with the implementation of OPDDs are provided in Appendix C to this
report, specifical y paragraphs C2-7 and C2-8.
2.4  Risks associated with switching a PEN conductor
Information
2.4.1  If the PEN conductor is switched (or broken) and the line (active) conductors remain
connected, then:
(a)  If the PEN conductor is associated with a single-phase system, in circuits
downstream of the open-circuit PEN conductor, exposed-conductive-parts can
attain a voltage up to the line to Earth voltage w
Official  ith respect to the general mass of the
Earth.
(b)  If the PEN conductor is associated with a three-phase system, in circuits downstream
the
of the open-circuit PEN conductor, exposed-conductive-parts can attain a voltage
exceeding the line to Earth voltage with respect to the general mass of the Earth.
2.4.2  The actual touch-voltage  experienced depends on a number of factors, including, in
three-phase systems, the balance of loads across the phases. Within buildings, main
under
protective bonding helps reduce the available touch-voltage. Outside buildings, only
additional earth electrodes, with (usually impracticably) low values of earth electrode
resistance, can reduce the available touch-voltage.
2.4.3  There can also be situations in which switching the incoming MEN conductor can lead to
simultaneously  accessible exposed-conductive-parts that are connected to different
earthing systems. This can lead to situations where hazardous touch voltages exist
without faults being present.
Released
2.4.4  More detailed facts relating to these risks can be found in Sections  C3  and  C7  of
Appendix C to this report.
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2.5  Risks associated with switching a neutral conductor other than a PEN
conductor
2.5.1  In a single-phase system, if a neutral conductor is switched, or broken, then the neutral
conductor downstream of the switch or break will be at the same voltage as the line
(active) conductor. This can present a shock risk to persons working on the installation,
although this can be mitigated by safe working practices and properly proving dead
before starting work.
2.5.2  In a three-phase system:
(a)  If a neutral conductor is switched, or broken, but the line (active) conductors are not
1987
simultaneously switched, the neutral conductor downstream will attain a voltage,
with respect to the line (active) conductors that depends on the balance of loads on
the phases. This often leads to overvoltages that damage equipment connected
Act
downstream of the broken or switched neutral. Fires can also result.
(b)  Damage to equipment due to overvoltage can also be experienced with multipole
switching of all live (active and neutral) conductors, if the line (active) conductors are
opened after, or closed before, the neutral conductor.
2.5.3  More detailed facts relating to these risks can be found in Section C4 of Appendix C to
this report.
2.6  Risks associated with switching an earthing conductor (protective
conductor) other than a PEN conductor  Information
2.6.1  If a protective conductor is switched, and the live conductors, and in particular the line
(active) conductors are not switched, then there is a risk of electric shock at exposed-
conductive-parts downstream of the switched, or broken, protective conductor arising
from:
Official
(a)  Protective conductor currents of energized equipment; or
(b)  Inability for a fault current to return to the source via the protective conductor,
meaning the provisions for automatic disconnection of supply in a fault are
the
ineffective.
2.6.2  Except for plug and socket-outlet combinations, or where the switching of part of
equipment that has appropriate durability requirements and tests according to a relevant
product standard, there are concerns in the industry that switching devices in protective
under
conductors could fail, leading to a permanent loss of the protective conductor until a
repair can be effected. Such a fault might go undetected.
2.6.3  More detailed facts relating to these risks can be found in Section C5 of Appendix C to
this report.
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2.7  Risks associated with leaving the MEN conductor connected to an
installation which has other PEN conductors connected in energized
circuits in island mode
2.7.1  It is possible for neutral currents in PEN conductors to be diverted through other
conductive parts in connection with the general mass of Earth, especially where these
are connected via earthing or bonding to the PEN conductor in the installation. This can
lead to currents being returned through the MEN system  neutral as illustrated in
Figure C.1 (page 28). These currents can be hazardous to persons working on the MEN
network.
2.7.2  This risk could be mitigated by precluding the use of PEN conductors in energized parts
1987
of installations operating in island mode.
2.7.3  More detailed facts relating to these risks can be found in Section C6 of Appendix C to
Act
this report.
Information
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Review of technical decision for WorkSafe New Zealand
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3  Existing mitigation in place for the risks outlined in Section 2 of this
report
3.1  During my investigation, there was evidence that specific risks summarized in Section 2
of this report are mitigated, at least in part, by other provisions already in place.

3.2  The mitigation and recommended residual risk actions are summarized in Table 3.1.

1987
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Table 3.1 Potential mitigation already in place of risks associated with the removal of Clauses 2.3.2.1.2 (b) and (c) from AS/NZS 3000:2018
1987
Ref  Removal of
Potential hazard  Cause
For hazard
Mitigations already in
Recommended residual risk actions
provision in
detail, see
place
AS/NZS 3000
Paragraph
Act
1
2.3.2.1.2 (b)(i)  Electric shock
•  Hazardous touch-
2.4.1 and
Installing this type of
A.  Switching of PEN conductors appears to
and
voltages between
2.4.2, and
switching is highly likely
be permissible at present. Guidance or
2.3.2.1.2 (c)
simultaneously-
Appendix C  to involve licensed
standards are necessary to prevent
accessible exposed-
Paragraphs  workers/inspectors.
switching of PEN conductors.
conductive-parts
C3-2, C3-3,

connected to different
C3-6, C3-7,  Regulations 13 and 14 of  B.  It is advisable, for the implementation of
earthing systems
C3-8, C3-9,  the New Zealand
island mode switching, to not switch
(IEC 60364-4-41,
C7-2
Electricity (Safety)
MEN/PEN conductors in parts of electrical
Clause 411.3.1.1)
Regulations apply, and
installations that are to be islanded. This is
prescriptive controls in
necessary to prevent diverted neutral
place do not appear to
(PEN) currents from within an islanded
Information
preclude switching of
installation being conducted through the
PEN conductors.
general mass of the Earth.
2
2.3.2.1.2 (b)(i)  Electric shock
• Change of earthing
2.4.3 and
Installing this type of
and
resistances in ‘global
Appendix C  switching is highly likely
2.3.2.1.2 (c)
earthing’ system (see
Paragraphs  to involve licensed

Note 2).
C3-4, C7-2
workers/inspectors.
C.  Standard arrangements for automatic
Official

•  Hazardous touch-

switching of island mode are yet to be

voltages between
addressed.

simultaneously

the

accessible exposed-
D.  In a global market, not all products meet

conductive-parts
every country’s national requirements,
and without industry guidance, other

connected to different
earthing systems
countries have found particular safety

(IEC 60364-4-41,
issues associated with islanding. IEC

Clause 411.3.1.1)
63445 [reference 12] could be considered
under

for the system referencing conductor

switching.

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Review of technical decision for WorkSafe New Zealand
  Technology
Ref  Removal of
Potential hazard  Cause
For hazard
Mitigations already in
Recommended residual risk actions
provision in
detail, see
place
1987
AS/NZS 3000
Paragraph
3
2.3.2.1.2 (b)(i)  Electric shock (of  •  Diverted neutral
2.7.1 and
Manual disconnection of
NOTE:
those working on
currents from islanded
2.7.2, and
MEN conductor in
Act
guidance for
MEN network)
installation to
Appendix C  existing guidance (see
E.  Consider implementing requirements so
island
distributor MEN if this is  Paragraphs  Section C7 of this
that PEN conductors are not used in
switching in
not switched (and PEN
C6-1 to
report).
islanded installations. See also residual
development
conductors are not
C6-5
risk action B.
precluded in islanded
inclusive
installations)
4
2.3.2.1.2 (b)
Electric shock
•  Failure to disconnect
2.5.1 and
Installing this type of
during
live conductors on
2.5.2 and
switching is highly likely
maintenance
operation of devices
Appendix C  to involve licensed
that ought to provide
Sections C3  workers/inspectors.
Information
safe
and C4

disconnection/isolation
Product standards, such
5
2.3.2.1.2
Damage to
•  Disconnected neutral
2.5.1 and
as IEC 60947 series, IEC
(b)(ii),
equipment
in a three-phase
2.5.2 and
60947-6-1 and IEC
F.  Standards or guidance for other products,
2.3.2.1.2
system or circuit when
Appendix C  60669 series, contain
and installation arrangements, to replace
(b)(ii ) and
active (line) conductors  Sections C3  requirements that mimic
the provision of AS/NZS 3000 Clause
2.3.2.1.2
remain connected
and C4
AS/NZS 3000 Clause
2.3.2.1.2 (b)(ii) and (ii ) is necessary.
Official
(b)(iv)
2.3.2.1.2 (b)(ii) and (ii ).
6
2.3.2.1.2
Fire/burns
•
2.5.1 and
See Appendix F to this
  Disconnected neutral
(b)(ii),
in a three-phase
2.5.2 and
report.
the
2.3.2.1.2
system or circuit when
Appendix C
(b)(ii ) and
active (line) conductors  Sections C3
2.3.2.1.2
remain connected.
and C4
(b)(iv)
under
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Technology
Ref  Removal of
Potential hazard  Cause
For hazard
Mitigations already in
Recommended residual risk actions
provision in
detail, see
place
1987
AS/NZS 3000
Paragraph
7
2.3.2.1.2 (c)
Electric shock
•  Disconnected
2.6.1 and
Installing this type of
G.  Consider implementing necessary
protective conductor
2.6.2 and
switching is highly likely
requirements similar to BS 7671 with
Act
and high protective
Appendix C  to involve licensed
regard to switching of protective
conductor currents
Paragraph
workers/inspectors.
conductors (see Appendix D, D6). This will
C5-3

facilitate the use of OPDDs as well as
For non-automatic
transfer switching that also transfers the
arrangements, AS/NZS
protective (earthing) function between
4509.1 applies.
sources of supply, and preclude switching
8
2.3.2.1.2 (c)
Electric shock
•  Disconnected
2.6.1 and
Installing this type of
of protective conductors where live (active
protective conductor
2.6.2 and
switching is highly likely
and neutral) conductors are not switched.
and electrical fault that  Appendix C  to involve licensed

would normally
Paragraphs  workers/inspectors.
H.  Consider mandating standards for open-
conclude with
C5-4, C5-5

PEN detection devices (OPDDs), for
Information
automatic
example IET 01:2024 [reference 3], that
disconnection of
contain provisions for durability. It is noted
supply
that automatic transfer switching is
covered by IEC 60947-6-1 [reference 8],
which is already listed in the legislation.
IEC 63445 [reference 12] could also be
Official
considered.
NOTE 1:  In Table 3.1 electric shock generally means physiological harm, or death, from electric shock. Secondary effects of injury resulting from involuntary reactions due to contact
with electricity, are not precluded.
the
NOTE 2:  The term ‘global earthing system’ is defined in Clause 3.7.19 of IEC 61936-1. See Appendix B. In the context of this report, the safety advantages of multiple earth connections
in the MEN system, and via connected installations and their extraneous-conductive-parts, is intended.

under
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Review of technical decision for WorkSafe New Zealand
  Technology
4  Conclusion
4.1  This Section of the Report provides a conclusion summarizing the opinion of the expert
who conducted the review.
4.2  Changes to the Electricity (Safety) Regulations were necessary to safely implement
renewable technologies and consider provisions for supply continuity under certain
circumstances. Specifically, and with reference to Paragraph 1.2.3 of this report, it should
be noted that:
(a)  Switching of protective (earthing) and neutral conductors is necessary to facilitate
supply changeover/transfer; and to facilitate protection by OPDDs.
(b)  Switching of PEN conductors  would not, in ideal circumstances, be considered;
1987
however, unless the use of PEN conductors in installations is to be restricted, there
are risks to persons working on the MEN distribution system.
Act
4.3  The deletion of Clauses 2.3.2.1.2 (b) and (c) from AS/NZS 3000:2018 (including
Amendments 1, 2 and 3) [reference 2] for New Zealand was put in place to achieve the aim
outlined in Paragraph 1.2.3 of this report.
4.4  Table 3.1 outlines specific residual risks that result from the decision (see Paragraph 4.3
of this report), some of which are mitigated as identified in the table.
4.5  The residual risks identified in Table 3.1  can be summarised as follows, each of which
should be addressed by subsequent guidance and/or future relevant standards:
(a)  PEN conductors should not  be  switched  under all circumstances  and applied in
Information
conjunction with item 4.5(b).  (Residual risk action A in Table 3.1.)
(b)  It is recommended that PEN conductors are not  used  in parts of installations
energized in island mode. (Residual risk actions B an d E in Table 3.1.)
(c)  Standards or guidance for manual or automatic island mode switching arrangements
should be provided. (Residual risk actions B, C, D and E in Table 3.1.)
(d)  Not all product standards include timing arrangements for switching neutral
Official
conductors in conjunction with other live conductors. IEC 63445 [reference 12] could
be considered for the system referencing conductor switching.  (Residual risk
the
actions D and F in Table 3.1.)
(e)  Provisions should be put in place in standards or guidance, and relevant product
standards mandated where appropriate, to cover situations in which it is necessary
to switch an earthing (protective earth) conductor. (Residual risk actions D, G and H
in Table 3.1.)
under
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4.6  To  address the  residual risks associated with  switching the PEN conductor  outlined in
4.5(a), provision of guidance on, or standards for, switching this protective conductor is
recommended. This in turn would introduce a risk associated with islanding installations
that themselves contain PEN conductors that are intended to remain energized in island
mode. This is addressed in this report by recommending PEN conductors are not used in
parts of instal ations energized in island mode, see Paragraph 4.5(b) of this report.
4.7  With respect to the correspondence received from the New Zealand Electrical Inspectors
Association discussed in Paragraph 1.2.4, I have reviewed the correspondence following
for formation of an initial opinion, and, in my view, the hazards raised in that
correspondence have been described in Appendix C of this report, and any residual risks
1987
outlined in Section 3 of this report.
4.8  The review concluded that, on balance, the decision to deletion of Clauses 2.3.2.1.2 (b)
and (c) from AS/NZS 3000:2018 (including Amendments 1, 2 and 3) [reference 2] for New
Act
Zealand is technically justifiable, when the following is taken into account:

(a)  In terms of the switching of PEN conductors, see Paragraph 4.5 item (a), there is a
residual risk with existing installations operating in island mode, regardless of
whether the decision is taken to either:
(i)
switch  PEN conductors, specifical y the MEN neutral,  with the aim of
protecting those working on an MEN distribution network  (see
Paragraphs C6-1 to C6-5 inclusive of this report), or
Information
(ii)
to  not switch PEN conductors, specifically the MEN neutral,  whilst PEN
conductors in the installation remain energized (see Appendix C Paragraphs
C3-1 to C3-9 inclusive, Paragraphs C6-6 to C6-10 inclusive, and Section C7,
of this report).
(b)  Guidance and standards are being developed to address the residual risks outlined
Official
in Paragraph 4.5 items (b) to (e) inclusive of this report.

(c)  The application of guidance and standards (yet to be developed), relating to island
the
mode and supply transfer switching, and the use of open-PEN disconnection devices
(OPDDs),  would  be limited  or impeded  if Clauses 2.3.2.1.2 (b) and (c) from
AS/NZS 3000:2018 (including Amendments 1, 2 and 3) [reference 2]  had been
retained in their present form.
under
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Appendix A  References and related documents
No.  Reference*
1.  New Zealand Electricity (Safety) Amendment Regulations 2025, last accessed
18 February 2026 from:
https://www.legislation.govt.nz/regulation/public/2025/0225/latest/whole.html
2.  AS/NZS 3000:2018 (including Amendments 1, 2 and 3) Electrical installations “Wiring
Rules”
3.  Institution of Engineering and Technology Standard IET 01:2024 Open combined
protective and neutral (PEN) conductor detection devices (OPDDs) (IET, London,
ISBN 978-1-83953-885-8)
4.  WorkSafe New Zealand Technical Bulletin Connecting a generator to the wiring of a  1987
house or building following an emergency, last accessed 18 February 2026 from:
https://www.worksafe.govt.nz/dmsdocument/57543-technical-bulletin-connecting-a-
generator-to-the-wiring-of-a-house-or-building-following-an-emergency/latest/  Act
5.  AS/NZS 4509.1:2009 stand-alone power systems part 1: Safety and installation
6.  BS 7671:2018+A2:2022+ A3:2024 Requirements for Electrical Installations. IET Wiring
Regulations Eighteenth Edition
7.  IEC 60947-6-1:2005+AMD1:2013 Low-voltage switchgear and controlgear – Part 6-1:
Multiple functional equipment – Transfer switching equipment
8.  IEC 60947-6-1:2021 Low-voltage switchgear and controlgear – Part 6-1: Multiple
functional equipment – Transfer switching equipment
9.  IEC 60947-1:2007+AMD1:2000+AMD2:2014 Low-voltage switchgear and controlgear –
Part 1: General rules
Information
10. IEC 60947-1:2020 Low-voltage switchgear and controlgear – Part 1: General rules
11. IEC 60669-1:2017 Switches for household and similar fixed-electrical instal ations -
Part 1: General requirements
12. IEC 63445:2025 System referencing conductor switching device (SRCSD)
13. IEC 60364-5-53:2015 (HD 60364-5-57:2017) Electrical installations of buildings –
Part 5-53: Selection and erection of electrical equipment – Isolation, switching and
Official
control
14. Institution of Electrical Engineers General Rules Recommended for Wiring of the
Supply of Electrical Energy, Fourth Edition, 1903
the
15. Institution of Electrical Engineers Wiring Rules, Seventh Edition 1916
16. Institution of Electrical Engineers Regulations for the Electrical Equipment of
Buildings, Fourteenth Edition 1966
17.  linked switch. (n.d.) McGraw-Hill Dictionary of Architecture and Construction. (2003).
under
Retrieved 17 February 2026 from
https://encyclopedia2.thefreedictionary.com/linked+switch
18. BIPM The International System of Units (SI) 9th Edition 2019 (updated to 2024)
19. NIST Special Publication 811 Guide to the International System of Units (SI)
20. NIST Technical Note 1297 Guidelines for Evaluating and Expressing the Uncertainty of
NIST Measurement Results 1994 Edition
21. IEC 61936-1:2021 Power installations exceeding 1 kV AC and 1,5 kV DC. Part 1: AC
22. IEC 60364-1:2025 Ed 6.0 Low-voltage electrical installations - Part 1: Fundamental
Released
principles, assessment of general characteristics, and definitions

* References which are without a date or revision / version are intended to refer the reader to the latest revision / version.
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Appendix B  Abbreviations and specialist terms
Abbreviations for SI Units, SI Derived Units, and related Non-SI Units are not listed here due to
their widespread use and standard application. Details of these units can be found in
references 18 and 19.
Term
Meaning
AC
Alternating current
Note:  ‘a.c.’ is used in AS/NZS 3000, and in older IEC, CENELEC and British
standards. In the text of this Report, ‘AC’ is used, following current IEC
usage, unless quoting parts of such standards verbatim.
AS/NZS
Australian Standard/New Zealand Standard (National Standards jointly published by
1987
Standards Australia and Standards New Zealand)
BIPM
Bureau International des Poids et Mesures
(International Bureau of Weights and Measures)
BS
British Standard (UK National Standards)
Act
DC
Direct current
NOTE:  ‘d.c.’ is used in AS/NZS 3000, and in older IEC, CENELEC and British
standards. In the text of this Report, ‘DC’ is used, following current IEC
usage, unless quoting such standards directly.
Diverted neutral
Load currents that return to the electrical energy source via conductive paths other
current
than a protective earth and neutral (PEN) conductor. Such conductive paths include
extraneous-conductive-parts, earth electrodes, and the general mass of the Earth.
EN
Euro-Norm (European Union Regional Standard Standard)
IEC
International Electrotechnical Commission
IET
Institution of Engineering and Technology (formerly the IEE)
Information
IEE
Institution of Electrical Engineers
Global earthing
See IEC 61936-1 [reference 21] Clause 3.7.19, which is as follows:
system
3.7.19
global earthing system
Equivalent earthing system created by the interconnection of local earthing systems
that ensures, by the proximity of the earthing systems, there are no dangerous touch
Official
voltages
NOTE 1 to entry  Such systems permit the division of earth fault current in a way that results
in a reduction of the earth potential rise at the local earthing system. Such a system could be
said to form a quasi-equipotential surface.
the
NOTE 2 to entry  The existence of a global earthing system may be determined by sample
measurements or calculations for typical systems. Typical examples of global earthing systems
are in city centres, urban or industrial areas with distributed low- and high-voltage earthing.
Island mode
Operating mode of an electrical installation in which it is disconnected from the
public distribution network, temporarily or permanently, and loads within the
installation are supplied by one or more local sources of energy.
under
NOTE:  sometimes, the term ‘grid independent’ is used for an electrical installation
that is permanently disconnected from the public distribution network.
MEN
Multiple earthed neutral
ISO
International Organisation for Standardisation
NIST
National Institute of Standards and Technology (United States of America)
PEN
Protective earth and neutral (combined)
SI
Système Internationale (International System of Units)
SRCSD
System referencing conductor switching device
Released
System
A conductor between a live part and an earthing arrangement, enabling the live part
referencing
to be substantially at the same potential as the earthing arrangement. The system
conductor
referencing conductor is neither a neutral conductor nor a protective conductor.
See IEC 60364-1:2025 [reference 22] Clause 1.8.4.
UK
United Kingdom

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Appendix C  Facts associated with removal of Clauses 2.3.2.1.2 (b) and (c) from
AS/NZS 3000:2018 and associated risks
C1  Clause 2.3.2.1.2 of AS/NZS 3000:2018 [reference 2]
C1-1  Clause 2.3.2.1.2 of AS/NZS 3000:2018 [reference 2] is as follows (highlights are made for
clarity in later Paragraphs of this review report):
2.3.2.1.2 Alternating current systems
Provisions for isolation of conductors in a.c. systems are as follows:
(a)  Active conductors All active conductors of an a.c. circuit shall be capable of being isolated by a
device for isolation.
1987

(b)  Neutral conductor:
(i)  No switch or circuit-breaker shall be inserted in the neutral conductor—
Act
(A)  of consumer mains; or
(B)  where the neutral conductor is used as a combined protective earthing and neutral
(PEN) conductor for protective earthing of any portion of an electrical installation.
NOTE: This requirement applies to situations such as an earth sheath return (ESR) system
or a submain neutral used for earthing of an electrical installation in an outbuilding in
accordance with Clause 5.5.3.1.
(ii)  A switch or circuit-breaker may operate in the neutral conductor of circuits other than those
in Item (i) where—
(A)  the neutral pole of a multi-pole switch or circuit-breaker, having an appropriate short-
Information
circuit breaking and making capacity, is linked and arranged to switch substantially
together with all active poles; or
(B)  the switch or circuit-breaker is linked with corresponding switches so that the neutral
contact cannot remain open when the active contacts are closed.
A switched neutral pole shall not open before and shall not close after the active pole(s).
Official
(iii) Where an item of switchgear is required to disconnect all live conductors of a circuit, it shall
be of a type such that the neutral conductor cannot be disconnected or reconnected without
the respective active conductors also being disconnected or reconnected.
the
NOTE: The manual disconnection and connection of neutral conductors should be as
follows:
(a)  The active conductors should be disconnected before the neutral conductors.
(b)  The neutral conductors should be connected before the active conductors.
under
Refer to AS/NZS 4836 for safe work practices.
(iv) A switch in the control circuit of a fire pump shall operate in the neutral conductor in
accordance with Clause 7.2.5.6.4.
In accordance with Clause 2.5.1.1, no fuse shall be inserted in a neutral conductor.

(c)  Switching of earthing conductor prohibited  An earthing conductor shall not be isolated or
switched.
Released
A conductor used as a combined protective earthing and neutral (PEN) conductor shall not be
isolated or switched.

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C1-2  Clause 2.3.2.1.2 (b) of AS/NZS 3000:2018 [reference 2], highlighted with a blue outline in
Paragraph C1-1 of this report,  divided into four sub-clauses, numbered 2.3.2.1.2 (b)(i),
2.3.2.1.2 (b)(i ), 2.3.2.1.2 (b)(i i) and 2.3.2.1.2 (b)(iv). The sub-clauses deal with conditions
for, or limitation of, switching of, neutral conductors, including PEN conductors, and are
analysed in subsequent Sections of this report as follows:
(a)  Section C2 summarizes facts regarding the reasons for deletion of 2.3.2.1.2 (b) and
(c) of AS/NZS 3000:2018 [reference 2].
(b)  Section  C3  summarizes facts regarding risks associated with switching a PEN
conductor that 2.3.2.1.2 (b) (i) and the second paragraph of 2.3.2.1.2 (c) intend to
prevent.
(c)  Section C4 summarizes facts regarding the risks associated with switching a neutral
1987
conductor other than a PEN conductor, without opening the line (active) conductors,
that 2.3.2.1.2 (b) (i ) and (i i) intend to prevent.
Act
C1-3  Clause 2.3.2.1.2 (c) of AS/NZS 3000:2018 [reference 2], highlighted with a green outline
in Paragraph C1-1  of this report, requires that no switching is provided  in an earthing
conductor (protective conductor in IEC 60364 series and BS 7671) including a PEN
conductor. These are analysed in subsequent Sections of this report as follows:
(a)  Section  C3  summarizes facts regarding risks associated with switching a PEN
conductor that 2.3.2.1.2 (b) (i) and the second paragraph of 2.3.2.1.2 (c) intend to
prevent.
(b)  Section  C5  summarizes facts regarding the risks associated with switching of an
earthing conductor that  2.3.2.1.2 (c) of AS/NZS 3000:2018 [reference 2] intends to
Information
prevent.
C1-4  The deletion of Clause 2.3.2.1.2 (b)(iv) of AS/NZS 3000:2018 [reference 2] was, on review,
considered inconsequential, as it simply makes reference to two other Clauses, 7.2.5.6.4
and 2.5.1.1, neither of which are deleted by the Electricity (Safety) Amendment
Regulations 2025 [reference 1].  Official

C2  Reasons for deletion of 2.3.2.1.2 (b) and (c) of AS/NZS 3000:2018 [reference 2]
the
C2-1  Guidance is  under preparation  for switching arrangements for operation of electrical
installations in New Zealand in island mode. Guidance exists for carrying out the
operation manually at present (see Paragraph C2-6 of this report).
C2-2  Island mode is the mode of operation of an electrical installation in which installation is
disconnected from the grid, and supplied from a local source of energy  within the
under
installation, for example a rotary generator, or inverters supplied by batteries, wind,
and/or solar PV.
C2-3  For safety of those operating on a public supply network, it is known that operation of an
installation in island mode will involve disconnection of live (active and neutral)
conductors within the installation from the grid.
C2-4  A complicating factor is the multiple earthed neutral (MEN) arrangements can be
extended to other parts of an instal ation such as an outbuilding. There are two key
Released
aspects that might affect the use of MEN arrangements within an installation with
renewable energy systems in island mode:
(a)  Due to low fault currents associated with renewable technology inverters, RCDs are
often necessary, and these are not compatible with PEN conductors.
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(b)  It is generally considered dangerous practice to recombine neutral and protective
(earthing) functions once they are separated. BS 7671 requires that PEN conductors
cannot be formed by recombining neutral and protective conductors (see D5 of
Appendix D of this report).
C2-5  It is not known at this stage precisely how island mode switching arrangements will be
achieved in standards and guidance in New Zealand, especially given the complicating
factors outlined in Paragraph C2-4 of this report.
C2-6  However, standards and guidance are already in place for the manual temporary
connection of a generator by licensed electrical workers, see:
(a)  WorkSafe New Zealand Technical Bulletin Connecting a generator to the wiring of a
1987
house or building following an emergency [reference 4];
(b)  AS/NZS 4509.1  Stand-alone power systems part 1: Safety and installation
[reference 5].
Act
C2-7  Consideration was also given to the possible future use of protective devices that can
operate to disconnect electric vehicles from all live conductors, and the protective
earthing system, in the event of detection of conditions indicative of a broken PEN
conductor upstream of the supply to the electric vehicle charging equipment. The
Institution of Engineering and Technology (IET) in the UK published a standard for such
devices, IET 01:2024 [reference 3], termed ‘open PEN detection devices’ (OPDDs).
C2-8  During a fault resulting from a broken PEN conductor, touch-voltages on conductive parts
of electric vehicles connected to a charging point can, under certain circumstances,
Information
exceed the line-to-Earth voltage if the break in the PEN conductor is in a three-phase
portion of the distribution system. OPDDs remove the danger by disconnecting all live
(active and neutral) conductors, and, at the same time, the protective (earthing)
conductor to the charging point, which would otherwise continue to transfer the raised
PEN conductor potential to conductive parts of the vehicle. This necessarily requires
switching of the earthing conductor.
Official

C3  Risks associated with switching a PEN conductor
the
C3-1  Sub-clause 2.3.2.1.2 (b)(i) of AS/NZS 3000:2018 [reference 2]  requires that  neither  a
neutral conductor of the consumer mains, nor a PEN conductor, are switched.
C3-2  The effect of switching a PEN conductor is to remove both protective earthing and neutral
functions from exposed-conductive-parts downstream of the switch. The risks
associated with switching a PEN conductor depend on whether the circuit (or service)
under
associated with the PEN conductor is single-phase or three-phase, and whether multiple
earthing (MEN) provisions are available downstream of the disconnected PEN conductor.
C3-3  It is not desirable to switch a PEN conductor under any circumstances. Not all countries
enable switching of protective conductors in their national wiring codes. The UK is one
country that does, but even in the UK, switching of PEN conductors is precluded (see
Appendix D Section D4 of this report).
C3-4  If a PEN conductor is switched at the same time as the other live conductors:
(a)  The earthing resistances on an MEN distribution network as a whole are changed.
Released
(a)  Touch-voltages can develop between exposed-conductive-parts, and earthing
(protective) conductors, on both sides of the switched conductor.
C3-5  If a PEN conductor is switched and line (active) conductors are not also disconnected,
the resulting impact depends on the following factors:
(a)  whether the circuit or system is single-phase or three-phase; and
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(a)  if the PEN conductor is part of an MEN system, or there is bonding or fortuitous
contact with the Earth either directly or indirectly through extraneous-conductive-
parts, so that there is a PEN return path around the switched PEN conductor due to
low effective earth electrode resistance.
C3-6  In single-phase circuits and systems with PEN conductors, exposed-conductive-parts
downstream of an open-circuit PEN conductor can have a touch-voltage of up to the line-
to-Earth voltage with respect to the general mass of Earth. This risk can be reduced inside
buildings where main protective bonding is in place.
C3-7  In three-phase circuits and systems with PEN conductors, the PEN conductor
downstream of the open-circuit PEN conductor is a neutral, and will assume a voltage
1987
dependent on the balance of loads connected downstream of the open-circuit PEN
conductor, which appears as a touch-voltage with respect to the general mass of the
Earth at exposed-conductive-parts and, if applicable, bonded extraneous-conductive-
Act
parts downstream of the open-circuit PEN conductor. The touch-voltage, in some
conditions, can exceed the line-to-Earth voltage with respect to the general mass of
Earth, and in rare conditions could approach the line-to-line voltage.
C3-8  The touch-voltages described in Paragraphs C3-6 and C3-7 of this report can be reduced,
to an extent, by:
(a)  Provision of earth electrodes with very low values earth electrode resistances,
connected to the PEN conductor downstream of the disconnection. The values of
earth electrode resistance that reduces the possible touch-voltages to a level that
might be considered generally safe in dry conditions depends on the connected load.
Information
Based on calculations carried out for electric vehicle charging installations supplied
by protective multiple earthing (PME) systems in the UK, the values of earth electrode
resistance are generally only considered practicable in cases where there is
extensive metal ic contact with the ground (for example, buildings with a piled steel-
framed buildings). The calculated resistances are:
Official
(i)
In single-phase systems, values of earth electrode resistance of less than 1 Ω
would be needed to maintain touch-voltages below 70 V AC for supplies up to
100 A.
the
(ii)
In three-phase systems the touch-voltage developed depends on phase
unbalance. Similar values of earth electrode resistance would be required to
maintain touch-voltages below 70 V AC for supplies up to 100 A, unless phase
unbalance can be guaranteed to be better than 0.60 per unit and 0.37 per unit
under
in the second and third largest line currents respectively both with respect to
the largest line current (being 1.00 per unit).
(b)  Inside buildings, by provision of main protective bonding, although note that
conductive parts connected to the protective bonding, that are accessible outdoors,
will then be subject to a potentially dangerous touch-voltage.
C3-9  In the case of a dangerous touch-voltage described in Paragraphs C3-6 and C3-7 of this
report, neither overcurrent protective devices nor residual current devices (RCDs) wil
Released
operate to provide automatic disconnection of the touch-voltage.

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C4  Risks associated with switching a neutral conductor other than a PEN conductor
C4-1  Sub-clauses 2.3.2.1.2 (b)(i ), 2.3.2.1.2 (b)(i i) and 2.3.2.1.2 (b)(iv) of AS/NZS 3000:2018
[reference 2] relate to conditions that must be satisfied for switching a neutral conductor
(other than a PEN conductor). These can be summarized as follows:
(a)  The neutral is not to be switched without also switching the associated active (line)
conductors.
(b)  When switching al  live (active and neutral) conductors, the switching is to be
arranged so that either:
(i)
all live (active and neutral) poles are linked so that all live contacts make and
break at substantially the same time; or
1987
(ii)
all live (active and neutral) poles are linked so that the neutral contact does
not open before the active (line) contact(s), and the neutral contact does not
close after the active (line) contact(s).
Act
C4-2  In single-phase systems and circuits, disconnecting a neutral conductor without
switching the associated line conductors generally disconnects power from loads;
however, all live conductors downstream of the disconnected neutral conductor remain
live. This could post a shock risk to anyone maintaining the installation, including removal
of lamps at general lighting service points.
C4-3  In three-phase systems and circuits, disconnecting a neutral without also disconnecting
the active (line) conductors means that the neutral is ‘floating’ and will assume a voltage,
relative in the phasor world to the live conductors, based on the balance of the loads
Information
downstream of the disconnected neutral. In this case, the voltage between any line and
neutral could attain a voltage of up to the line-to-line voltage, or in rare cases with non-
unity power factor, exceed the line-to-line voltage.
C4-4  Undervoltage is often experienced by equipment in general; however, due to the
magnitude of overvoltage experienced by single-phase equipment connected between a
line and neutral downstream of the switched neutral, serious overvoltage can be
Official
experienced. Overvoltage from broken neutrals in three-phase systems has been known
to not only damage equipment, but also lead to fire. The situation in a real open neutral
situation is often exacerbated by the fact that, as modern equipment with internal
the
electronic and control circuitry becomes inoperative or is damaged by overvoltage, the
balance of loads is continually shifting.
C4-5  Where the timing arrangements summarized in Paragraph C4-1(b) of this report are not
met, the neutral can be disconnected when the live conductors are connected. This can
lead to the risks described in Paragraphs C4-2 to C4-4 inclusive of this report; however,
under
in this case, the risk of fire resulting is generally less because of the short time involved.
Damage to equipment, however, can still result, particularly if a three-phase circuit is
being switched.

C5  Risks associated with switching an earthing conductor (protective conductor)
other than a PEN conductor
Released
C5-1  Clause 2.3.2.1.2 (c) of AS/NZS 3000 [reference 2]  requires that  earthing (protective)
conductors are not switched or disconnected.
C5-2  Risks associated with switching of a PEN conductor are summarized in Section C3 of this
report.
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C5-3  Switching earthing (protective) conductors without switching live conductors is generally
considered dangerous as it removes the protective provision of automatic disconnection
of supply. If  a fault were to occur  under these conditions,  the fault would not be
disconnected, and exposed-conductive-parts would be at a hazardous live voltage with
respect to the general mass of the Earth.
C5-4  In many instal ations, protective conductor currents result from electromagnetic
compatibility filters, and if the protective conductor is open-circuit, such currents can
flow to Earth through someone in contact with exposed-conductive-parts. If the
protective conductor is interrupted to a number of items of equipment, or a number of
circuits, that remain live, the sum of protective conductor currents can, on their own, be
lethal with no electrical fault, unless the protective conductor remains continuous.  1987
C5-5  There is concern regarding switching of protective conductors (other than through the
removal and reinsertion of a multi-pole plug and socket-outlet), that if a switching device
has a protective conductor contact, this can, over time, fail. A user may be unaware of
Act
the damage, leading to permanent disconnection of the earthing (protective) conductor.
Such risks can be alleviated by only enabling switching of the protective conductor by
dedicated equipment to an appropriate product standard that includes durability tests,
and/or where there is monitoring of the earthing system through the protective
conductor.

C6  Risks associated with the use of PEN conductors and remote system referencing
connections in electrical installations operating in island mode
Information
C6-1  In system with TN-C or TN-C-S earthing arrangements, diverted neutral current is a term
used to describe neutral current, that would normally flow back to the source of energy
via the PEN conductor, but instead are diverted through other low resistance paths,
including:
(a)  fortuitous connection of protective (earthing) conductors, including PEN conductors,
with the ground, or conductive parts in contact with the ground;
Official
(b)  bonded extraneous-conductive-parts that form an effective low resistance earth
electrode (for example metallic non-electrical service pipework, or the steel frame of
the
a building);
(c)  exceptionally low resistance earth electrodes (for example where the steel frame of
a building is used as an earth electrode).
C6-2  The proportion of diverted neutral current depends on the earth electrode resistances,
under
soil resistivity, and presence of conductive material in the ground. It is not something that
is easy to predict without extensive investigation for a given site.
C6-3  If the PEN conductor of the MEN network remains connected to an electrical installation
operating in island mode, diverted neutral currents from PEN conductors in the
installation can return to the island mode source via the MEN network as a parallel path,
as il ustrated in Figure C.1. This can provide a risk to persons working on the supply
distribution network (MEN distribution system), even where the distribution system is de-
energized for the work to be carried out.
Released
C6-4  Whilst the proportion of diverted neutral current in many cases is likely to be small with
respect to load current, currents of only a few milliamperes can be fatal.
C6-5  If the diverted neutral current results from shared metalwork (for example, metallic non-
electrical service pipes) between two separate electrical instal ations, however, a large
proportion of diverted neutral current can be expected.

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Figure C.1 Example of path of possible diverted neutral currents
Distribution
Electrical
network
installation
Island mode
power source
Disconnected
in island mode
+ ‒
1987
Main building
Act
Load current
Outbuilding
Diverted neutral current
load
Information
Outbuilding

Official
NOTE 1:  See Paragraph C6-10 of this report regarding the earthing arrangement for
connecting the island mode power source.
NOTE 2:  Figure C.1 is intended to il ustrate a principle, and is not specific to supply and
the
installation arrangements any particular country.

C6-6  ‘System referencing’ is a term that is recently appearing in IEC standards, see
under
IEC 60364-1 [reference 22], to mean the connection of a live part or conductor to Earth
for the purpose of forming a suitable earthing arrangement associated with protection
against electric shock. The system referencing conductor is the conductor that connects
the live part to an earthing conductor to enable the live part to be substantial y at the
potential of the earthing arrangement.
C6-7  The location of the system referencing conductor is important to the operation of certain
protective devices.
C6-8  In installations where small-scale embedded generators are used to provide power to the
Released
installation in island mode, the available fault currents can be insufficient to operate
overcurrent protective devices, and residual current devices (RCDs) are necessary to
provide protection against electric shock.
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C6-9  If the system referencing conductor is not provided immediately after the grid-forming
embedded generator, the generator connecting circuit might not be effectively protected
against electric shock by automatic disconnection of supply, as an RCD in that circuit will
not operate for a fault in the embedded generator circuit.
C6-10  The arrangement shown in Figure C.1 effectively includes a ‘combining’ of neutral and
protective conductors from the perspective of the island mode source of supply at the
point  where the PEN conductor to the outbuilding is connected. The neutral bar
connection from the combined neutral and earth terminal acts as a system referencing
conductor. This is effectively  precluded  in IEC 60364-5-54:2011+AMD1:2021 (see
Paragraph  E6-1  in  Appendix E  of this report). It is not clear how such a conflicting
requirement might be interpreted in multi-source, or switchable-source, systems.
1987
Ideally, the system referencing conductor should be as close as possible to the island
mode source of supply (see Paragraph C6-9).
C7  Existing guidance for connecting temporary generators
Act
C7-1  The existing guidance for connecting temporary or stand-alone generators [references 4
and  5] address the risks outlined in Paragraphs C6-1  to  C6-5, by temporarily
disconnecting the MEN connection to the installation.
C7-2  The existing guidance for connecting temporary or stand-alone generators [references 4
and  5] do not consider the fact that the MEN is to be disconnected. If this is not
appropriately insulated, or there are exposed-conductive parts connected to the
islanded installation that are simultaneously-accessible with exposed-conductive-parts
connected to the MEN system outside the installation, then dangerous potential
differences can be experienced.
Information

Official
the
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Appendix D  Provisions for and preclusions of switching protective, neutral
and PEN conductors in BS 7671
D1  General
D1-1  The current national electrical installation standard in the United Kingdom is
BS 7671:2018+A2:2022+A3:2024 [reference 6].
D2  Supply transfer arrangements
D2-1  The selection of switching and earthing arrangements for supply changeover, whether
automatic or manual, is specifically covered by Regulation 537.1.5 of BS 7671
[reference 6] which has the following provisions:
1987
537.1.5 Where an installation is supplied from more than one source of energy, one of which requires
a means of earthing independent of the means of earthing of other sources and it is necessary to
provide that not more than one means of earthing is applied at any time, a switching device may be
Act
inserted in the connection between the neutral point and the means of earthing, provided that the
device is:
(i) a multipole, linked switching device arranged to disconnect and connect the earthing conductor
for the appropriate source at substantially the same time as the related live conductors, or
(ii) a switching device interlocked with a multipole, linked switching device inserted in the related
live conductors such that the earthing conductor for the appropriate source shall not be interrupted
before the related live conductors and shall be re-established not later than when the live conductors
are reconnected.
Information
Switching devices provided in accordance with (i) and (ii) shall meet the requirements of Chapter 46
for a device for isolation.
D3  Switching of the neutral conductor
D3-1  Regulation 132.14.2 is a general requirement of BS 7671 [reference 6] and contains the
provision that only linked switches or circuit-breakers, either of which also breaks the line
Official
conductors, may be used in the neutral conductor:
132.14.2 No switch or circuit-breaker, except where linked, or fuse, shall be inserted in an earthed
the
neutral conductor. Any linked switch or linked circuit-breaker inserted in an earthed neutral conductor
shall be arranged to break all the related line conductors.
D4  Preclusion of switching a PEN conductor
D4-1  BS 7671 [reference 6] precludes switching of a PEN conductor, see Regulation 411.4.3:
under
411.4.3 In a fixed installation, a single conductor may serve both as a protective conductor and as a
neutral conductor (PEN conductor) provided that the requirements of Regulation 543.4 are satisfied.
No switching or isolating device shall be inserted in the PEN conductor.
NOTE:  Regulation 8(4) of the Electricity Safety, Quality and Continuity Regulations prohibits the
use of PEN conductors in consumers’ installations.
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D5  Preclusion of forming a PEN conductor from separate neutral and protective
conductors
D5-1  BS 7671 [reference 6]  precludes  the recombining of separate neutral and protective
conductors to re-establish a PEN conductor, see Regulation 543.4.3:
543.4.3 If, from any point of the installation, the neutral and protective functions are provided by
separate conductors, those conductors shall not then be reconnected together beyond that point. At
the point of separation, separate terminals or bars shall be provided for the protective and neutral
conductors. The PEN conductor shall be connected to the terminals or bar intended for the protective
earthing conductor and the neutral conductor. The conductance of the terminal link or bar shall be not
less than that specified in Regulation 543.4.5.
1987
D6  Switching of the protective conductor (other than a PEN conductor)
D6-1  Regulation 543.3.3.101 of BS 7671 [reference 6] contains the fol owing provisions:
Act
543.3.3.101 No switching device shall be inserted in a protective conductor, except:
(i) as permitted by Regulation 537.1.5
(ii) a multipole, linked switching device in which the protective conductor circuit is not interrupted
before the live conductors and is re-established not later than when the live conductors are
reconnected
(iii) a switching device interlocked with a multipole, linked switching device inserted in the live
conductors such that the protective conductor circuit shall not be interrupted before the live
conductors and shall be re-established not later than when the live conductors are reconnected, or
Information
(iv) a multipole plug-in device in which the protective conductor circuit shall not be interrupted before
the live conductors and shall be re-established not later than when the live conductors are reconnected.
Switching devices provided in accordance with (i), (ii), (iii) and (iv) shall meet the requirements of
Chapter 46 and Section 537 for a device for isolation.
Official
Joints for test purposes that can be disconnected only by the use of a tool may be inserted in a
protective conductor.
D6-2  Switching of a protective conductor (including an earthing conductor) is by a single-pole
the
switching device inserted in the conductor, interlocked with a multipole linked switch
that operates to disconnect live conductors, is therefore clearly facilitated by BS 7671
[reference 6], using the options in:
(a)  indent (i) to Regulation 534.3.3.101, via the option in indent (i ) to Regulation 537.1.3;
under
or
(b)  indent (i i) to Regulation 534.3.3.101.
D7  Meaning of the term ‘linked switch’ in BS 7671
D7-1  The term linked switch has been used in BS 7671, and the predecessor UK industry
standard commonly known as the ‘IEE Wiring Regulations’, published by the Institution
of Electrical Engineers (IEE) for a period exceeding 120 years. A definition for the term first
appeared in Regulation 100 of the Fourth Edition of the IEE Wiring Regulations
Released
[reference 14] which was published in 1903:
100. Linked switches.– Linked switches are single-pole switches fixed on conductors of different
polarity linked together mechanically so as to operate simultaneously.
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D7-2  The definition cited in Paragraph D7-1 of this Appendix remained in use in subsequent
Editions of the IEE Wiring Regulations, from the Fourth to the Sixth, until the Seventh
Edition [reference 15] was published in 1916, which contained the following definition
introducing a ‘definite sequence’ of operation:
Switch, linked. A switch the blades of which are so linked mechanically as to make or break all poles
simultaneously or in a definite sequence.
The definition remained unchanged until the Fourteenth Edition [reference 16] published
in 1966 (see Paragraph D7-3 of this Appendix).
D7-3  The current definition in Part 2 of BS 7671:2018+A2:2022+A3:2024 [reference 6] is:  1987
Switch, linked. A switch the contacts of which are so arranged as to make or break all poles
simultaneously or in a definite sequence.
This definition has not changed since the Fourteenth Edition of the IEE Wiring
Act
Regulations, first published in 1966 [reference 16].
D7-4  There is no definitive statement in the current edition of BS 7671 [reference 6] that the
poles of a ‘linked switch’ are required to be mechanically linked; however the following
ought to be considered:
(a)  It is generally considered in the industry that the term ‘linked switch’ refers to a
multipole switch in which the linkages are mechanical in nature. For example, the
McGraw-Hill Dictionary of Architecture and Construction [reference 17] defines the
Information
term ‘linked switch’ as:
Two or more electric switches which are mechanically connected by operating arms or levers, so as
to operate at the same time or in a desired sequence;
and
(b)  BS 7671 [reference 6] uses the term ‘interlocked’ in relation to electrical linking in
Official
indent (i ) of Regulation 537.1.5, and indent (i i) of Regulation 543.3.3.101;
and
the
(c)  BS 7671 [reference 6] implements the technical intent of the HD 60364 series
published by CENELEC, as listed in the Preface. The facts regarding the technical
intent in respect of multipole switching devices being required be mechanically
linked are presented in Appendix E, E7 of this report.
under
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Appendix E  Provisions for and preclusions of switching protective, neutral
and PEN conductors in IEC 60364 series
E1  General
E1-1  Relationship with AS/NZS 3000
E1-1-1
The preface to AS/NZS 3000:2018 [reference 2] states that one of the objectives of
the revision from AS/NZS 3000:2007 was to ‘maintain alignment with IEC 60364, Low
voltage electrical installations (series)’.
E1-2  Relationship with BS 7671
E1-2-1
BS 7671:2018+A2:2022+ A3:2024 [reference 6] implements the technical intent of 1987
CENELEC harmonized documents (HDs) as shown in the Preface to the standard.
HD 60364 series implements IEC 60364 series in CENELEC.
Act
E2  Supply transfer arrangements
E2-1  IEC 60364 series appears to leave supply transfer switching to IEC 60947-6-1. It is not
clear what conditions pertain when switching between supplies that have different, and
separate, earthing arrangements.
E2-2  IEC 60364-1:2025 defines a ‘system referencing conductor’ to enable earthing of a live
conductor to be established, preventing the need to switch a protective conductor, see
Clause 1.8.4:
1.8.4 System-referencing-conductors
Information
A system-referencing-conductor (SRC) is a conductor between a live part and an earthing
arrangement, enabling the live part to be substantially at the potential of the earthing arrangement.
The SRC is neither a neutral conductor nor a protective conductor.
NOTE The application of SRC, shown in Figure 9, Figure 10, Figure 11, Figure 12 and Figure 13, is
given to help define the characteristic behaviour of the electric systems.
Official
E3  Switching of the neutral conductor
E3-1  Clause  530.3.2  of IEC 60364-5-53:2015  precludes switching of the neutral conductor
unless the associated line (active) conductors are also switched:
the
530.3.2  Except as provided in 536.2.2.7, in multiphase circuits, single-pole devices shall not be
inserted in the neutral conductor.
In single-phase circuits single-pole devices shall not be inserted in the neutral conductor, unless a
residual current device complying with the rules of 413.1 of IEC 60364-4-41 is provided on the supply
under
side.
E4  Preclusion of switching a PEN conductor
E4-1  IEC 60364-4-41:2005+A1:2017 precludes the switching of a PEN conductor, see Clause
411.4.3:
411.4.3 In fixed installations, a single conductor may serve both as a protective conductor and as a
neutral conductor (PEN conductor) provided that the requirements of 543.4 of IEC 60364-5-54 are
Released
satisfied. No switching or isolating device shall be inserted in the PEN conductor.
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E5  Switching of the protective conductor (other than a PEN conductor)
E5-1  IEC 60364-5-54:2011+AMD1:2021 precludes the switching of a protective conductor, see
Clause 543.3.3:
NOTE:  Some countries, including the United Kingdom, allow switching of the protective
conductor under specified conditions.
543.3.3 No switching device shall be inserted in the protective conductor, but joints which can be
disconnected for test purposes by use of a tool may be provided.
E5-2  Similarly, IEC 60364-1, Clause 1.8.3, precludes switching protective conductors:
1.8.3 Protective conductors
1987
1.8.3.1 General
Protective conductors are those conductors used for protective purposes. Protective conductors
Act
are classified into:
– protective earthing conductors;
– protective bonding conductors.
In a protective conductor the electrical continuity shall be maintained. Accordingly, no switching
device shall be inserted.
E5-3  A distinction that needs to be raised in respect of Paragraph E5-2 of this Appendix, is that
Information
switching of a protective conductor need not occur, if the connection of a live conductor
of the installation to Earth is not classified as a protective conductor, and a the term
system referencing conductor is defined. See Section E2 of this Appendix.
E6  Preclusion of forming a PEN conductor from separate neutral and protective
conductors
Official
E6-1  IEC 60364-5-54:2011+AMD1:2021  precludes  the recombining of separate neutral and
protective conductors to re-establish a PEN conductor, see Clause 543.4.3:
543.4.3 If, from any point of the installation, the neutral/mid-point/line and protective functions are
the
provided by separate conductors, it is not permitted to connect the neutral/mid-point/line conductor
to any other earthed part of the installation. However, it  is permitted to form more than one
neutral/mid-point/line conductor and more than one protective conductor from the PEN, PEL or PEM
conductor respectively.
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E7  Requirements for linked switching in IEC 60364-5-53:2015
E7-1  Section 530.3 contains the following provisions:
530.3 General and common requirements
This part of IEC 60364 shall provide compliance with the measures of protection for safety, the
requirements for proper functioning for intended use of the installation, and the requirements
appropriate to the external influences foreseen. Every item of equipment shall be selected and erected
so as to allow compliance with the rules stated in the following clauses of this part and the relevant
rules in other parts of this standard.
The requirements of this part are supplementary to the common rules given in IEC 60364-5-51.  1987
530.3.1 The moving contacts of all poles of multipole devices shall be so coupled mechanically that
they make and break substantially together, except that contacts solely intended for the neutral may
close before and open after the other contacts.
Act
530.3.2  Except as provided in 536.2.2.7, in multiphase circuits, single-pole devices shall not be
inserted in the neutral conductor.
In single-phase circuits single-pole devices shall not be inserted in the neutral conductor, unless a
residual current device complying with the rules of 413.1 of IEC 60364-4-41 is provided on the supply
side.
530.3.3 Devices embodying more than one function shall comply with all the requirements of this
part appropriate to each separate function.
Information
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Appendix F  Provisions for switching the neutral conductor in relevant
product standards referenced in Schedule 4 to the New Zealand
Electrical Safety (Amendment) Regulations 2025
F1  IEC 60947-1
F1-1  Clause 8.1.9 of IEC 60947-1:2020 [reference 10] has the following provisions in respect
of the neutral pole:
8.1.9 Additional requirements for equipment provided with a neutral pole
When an equipment is provided with a pole intended only for connecting the neutral conductor, this
1987
pole shall be clearly identified to that effect by the letter "N" (see 8.1.8.4).
A switched neutral pole shall break not before and shall make not after the other poles. Act
If a pole having an appropriate short-circuit breaking and making capacity (see 3.7.14 and 3.7.15) is
used as a neutral pole, then all poles, including the neutral pole, may operate substantially together.
The neutral pole may be fitted with an overcurrent release.
For equipment having a value of conventional thermal current (free air or enclosed, see 5.3.2.1 and
5.3.2.2) not exceeding 63 A, this value shall be identical for all poles.
For higher conventional thermal current values, the neutral pole may have a value of conventional
thermal current different from that of the other poles, but not less than half that value or 63 A,
whichever is the higher.
Information

F2  IEC 60947-6-1
F2-1  IEC 60947-6-1:2021 [reference 8] includes a clear, normative, requirement for the live
conductor poles (lines and neutral) of multipole transfer switches to be mechanically
coupled so they operate substantially at the same time. The same Clause also references
Official
IEC 60947-1:2020 Clause 8.1.9 in respect of the neutral pole (see Paragraph F1-1 of this
Appendix).
the
8.1.5 Opening and closing of main contacts
The main moving contacts of all phase poles of the switching device of a multipole TSE shall be so
mechanically coupled that they make and break substantially together, whether operated manually,
remotely, or automatically.
under
The manual actuator of the TSE shall be insulated. The requirements of 8.1.5.1 of IEC 60947-1:2020
applies.
There shall be no path or opening which allows incandescent particles to be discharged from the area
of the manual operating means.
For TSE equipped with neutral poles, 8.1.9 of IEC 60947-1:2020 applies.
For any TSE with manual operating means intended for on-load use, opening and closing of the main
contacts shall be independent of the speed with which the manual operating means is operated.
Released
If the manual means is intended only for off-load use with all sources de-energized and is so marked
according to Table 2 item 1.3, this requirement does not apply.

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Technology
F3  IEC 60669-1
F3-1  IEC 60669-1:2017  [reference 11]  Clause  14.4  contains provisions for the timing of
switching of the neutral contact in three-pole plus switched neutral switches conforming
to the standard. (See Paragraph F3-2 of this Appendix regarding classification of switches
in terms of pattern numbers according to Clause 7.1 of the standard.)
14.4 Making and breaking
Switches of patter numbers 2, 3,  04 and 6/2 shall make and break all poles substantially
simultaneously except that for switches of pattern number 03, the neutral shall not make after or break
before the other poles.
1987
Compliance is checked by inspection and by manual test when the switch is mounted with the cover,
cover plates and actuating members installed as for normal use.

Act
F3-2  Switches to IEC 60669-1 are classified according to their pattern number as per
Clause 7.1 of the standard (Figure 8 of the standard is reproduced in Figure F.1 on page 38
of this report):
7 Classification
Switches are classified
7.1 according to the possible connections (see Figure 8) Information

Pattern number
—  single-pole switches  ...................................................................................
1
—  double-pole switches ..................................................................................
2
—  three-pole switches .....................................................................................
3
Official
—  three-pole plus switched neutral switches  ..................................................
03
—  two-way switches  .......................................................................................
6
—  two-circuit switches with a common incoming line ...................................
5
the
—  two-way switches with one off-position  .....................................................
4
—  two-way double-pole switches  ...................................................................
6/2
—  two-way reversing switches (or intermediate switches) .............................
7
under
NOTE 1 Two or more switches having the same or different pattern numbers can be mounted on a common base.
NOTE 2 For the pattern number for which an off-position is considered, the above classification refers also to
push-but on switches and momentary contact switches.
Released
Ref: GKT-GENC-REP-0004
© G Kenyon Technology Ltd 2026
Page 37 of 38
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Published for Information

G Kenyon
Review of technical decision for WorkSafe New Zealand
Technology
Figure F.1 Figure 8 from IEC 60669-1:2017
1987
Act
Information
Official
the
under

Released
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Document Outline