IEC 61936-1:2010/AMD1:2014

IEC 61936-1 ®
Edition 2.0 2014-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
A MENDMENT 1
AM ENDEMENT 1
Power installations exceeding 1 kV a.c. –
Part 1: Common rules
Installations électriques en courant alternatif de puissance supérieure à 1 kV –
Partie 1: Règles communes
IEC 61936-1:2010-08/AMD1:2014-02(EN-FR)

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IEC 61936-1 ®
Edition 2.0 2014-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
A MENDMENT 1
AM ENDEMENT 1
Power installations exceeding 1 kV a.c. –

Part 1: Common rules
Installations électriques en courant alternatif de puissance supérieure à 1 kV –

Partie 1: Règles communes
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX R
ICS 29.020; 29.080.01 ISBN 978-2-8322-1384-1

– 2 – 61936-1 Amend.1 © IEC:2014
FOREWORD
This amendment has been prepared by IEC technical committee 99: System engineering and
erection of electrical power installations in systems with nominal voltages above 1 kV a.c. and
1,5 kV d.c., particularly concerning safety aspects.
The text of this amendment is based on the following documents:
FDIS Report on voting
99/129/FDIS 99/131/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
_____________
Foreword
Insert, in the existing list of differences in some countries, the following new items:

• 7.2.6: 50 mm × 200 mm mesh is not accepted (Australia)
• 7.2.6: Guidance regarding fence construction can be found at ENA Doc 015 (Australia)
• 8.7.1: Fire rating of barriers must be a minimum fire rating of 120 minutes (Australia)
• 8.7.2: The dimensions G and G are to be measured from the inside edge wall of any
1 2
bund wall rather than the measured point shown in Figure 7a) and 7b) from the
transformer where the bund wall is wider than the transformer (Australia)
• 8.8.1.3: Spill containment should extend by 50 % of the height of the transformer
(Australia)
• Figure 7a): The dimensions G and G are to be measured from the inside edge wall of
1 2
any bund wall rather than the measured point shown in Figure 7a) from the transformer
where the bund wall is wider than the transformer (Australia)
• Figure 7b): The dimensions G and G are to be measured from the inside edge wall of
1 2
any bund wall rather than the measured point shown in Figure 7b) from the transformer
where the bund wall is wider than the transformer (Australia)
• Clause 10: For requirements regarding earthing refer to AS 2067, Substations and High
Voltage Installations (Australia)
1 Scope
Add the following new item e) after d):
e) Electrical installations erected on offshore platforms e.g. offshore wind power farms.

61936-1 Amend.1 © IEC:2014 – 3 –
Modify the fifth dashed item in the last list of this clause as follows:
– installations on ships according to IEC 60092 [34] series and offshore units according to
IEC 61892 [35] series, which are used in the offshore petroleum industry for drilling,
processing and storage purposes.
Modify the first paragraph after the last list of this clause as follows:
This standard does not apply to the design of prefabricated, type-tested switchgear and high
voltage/low voltage prefabricated substation, for which separate IEC standards exist.
2 Normative references
Add, to the existing list, the title of the following standards:
IEC/TS 61463, Bushings – Seismic qualification
IEC 62271-206, High-voltage switchgear and controlgear – Part 206: Voltage presence
indicating systems for rated voltages above 1 kV and up to and including 52 kV
IEC 62271-207, High-voltage switchgear and controlgear – Part 207: Seismic qualification for
gas-insulated switchgear assemblies for rated voltages above 52 kV
IEC/TR 62271-300, High-voltage switchgear and controlgear – Part 300: Seismic qualification
of alternating current circuit-breakers
IEC 82079-1, Preparation of instructions for use – Structuring, content and presentation –
Part 1: General principles and detailed requirements
Replace the reference to IEC 62271-1:2007 by the following new reference:
IEC 62271-1:2007, High-voltage switchgear and controlgear – Part 1: Common specifications
Amendment 1:2011
4.1.2 Agreements between supplier (manufacturer) and user
Add the following four new lines to the existing table:
Subclause Item
4.3.9 Special conditions and requirements for seismic environment
4.4.3.5 Special conditions and requirements for vibrations
8.7.2.1 Reduction of distances G /G
1 2
10.2.1 Fundamental requirements for design of the earthing system

4.2.4 Short-circuit current
Add the following Note 1 after the first paragraph:
NOTE 1 Where an installation has on-site generation, motors or parallel operation with a network (co-generation),
fault levels can increase.
Change the existing Note 1 to Note 2, and the existing Note 2 to Note 3.

– 4 – 61936-1 Amend.1 © IEC:2014
4.2.7 Electric and magnetic fields
Modify the existing note as follows:
NOTE National and/or international regulations may specify acceptable levels. Further information is available
from International Commission on Non-Ionizing Radiation Protection (ICNIRP) or IEEE.
4.3.1 Equipment and supporting structures
Replace the existing Note 1 by the following normal text:
Consideration shall be given to temporary stresses and loads that may be applied during
construction or maintenance procedures. Specific equipment can be affected by cyclic loads
and stresses due to thermal expansions (refer to specific equipment standards).
Delete Note 2.
Add, at the end of the second list, the following new item:
– seismic loads.
4.3.9 Vibration
Replace the existing title and text of this subclause with the following:
4.3.9 Seismic loads
Special conditions and requirements shall be agreed between user and supplier. (See also
4.4.3.5 Vibration).
Installations situated in a seismic environment shall be designed to take this into account.
Where load specifications apply to the installation of civil work or equipment to meet seismic
conditions, then these specifications shall be observed.
Seismic loads shall be dealt with in accordance with appropriate standards for power
installations: e.g. IEC 62271-207 for GIS, IEC/TR 62271-300 for circuit-breakers and
IEC/TS 61463 for bushings.
The following measures shall be taken into account:
a) Any individual equipment shall be designed to withstand the dynamic forces resulting from
the vertical and horizontal motions of the soil. These effects may be modified by the
response of the foundation and/or the supporting frame and/or the floor in which this
equipment is installed. The response spectrum of the earthquake shall be considered for
the design of the equipment.
b) The layout shall be chosen in order to limit the loads due to interconnections between
adjoining devices needing to accommodate large relatively axial, lateral, torsional or other
movements to acceptable values. Attention should be paid to other stresses which may
develop during an earthquake.
4.4.3.5 Vibration
Replace the existing text of this subclause with the following:
Special conditions and requirements shall be agreed between user and supplier. (See also
4.3.9 Seismic loads).
61936-1 Amend.1 © IEC:2014 – 5 –
Vibration caused by wind, electromagnetic stresses, traffic (e. g. temporary road and railway
traffic) and industrial processes shall be considered. The withstand capability of equipment
against vibrations shall be given by the manufacturer.
The service stresses of equipment, which may be transmitted through a common monolithic
foundation or floor (for example opening/reclosing of circuit-breakers) shall be taken into
account.
5.4.1 General
Replace the first sentence of the second paragraph with the following:
If parts of an installation can be separated from each other by a disconnector, these parts
shall be tested at the rated impulse withstand voltage for the isolating distance (see Tables 1a
and 1b as well as Tables 2a and 2b of IEC 62271-1:2007, Amendment 1:2011).
Table 2 – Minimum clearances in air – Voltage range II (U > 245 kV)
m
Replace the existing Table 2 with the following new Table 2:
Table 2 – Minimum clearances in air – Voltage range II
(U > 245 kV)
m
Highest Rated Rated Rated
voltage for lightning switching Minimum switching Minimum
installation impulse impulse phase-to-earth impulse phase-to-phase
withstand withstand clearance withstand clearance
a
voltage voltage voltage
Voltage
U
U U U
p
m s s
Conductor Rod Conductor Rod
range
1,2/50 µs Phase-to- – – Phase-to- – –

r.m.s.
(peak value) earth phase
structure structure conductor conductor
250/2 500 µs 250/2 500 µs parallel
(peak value) N (peak value)
kV kV kV mm kV mm
850/950 1 600
750 1 900 1 125 2 300 2 600
b
1 700
950/1 050 1 800
850 2 400 1 275 2 600 3 100
b
1 900
950/1 050 1 800
850 2 400 1 275 2 600 3 100
b
362 1 900
1 050/1 175 950 2 200 2 900 1 425 3 100 3 600
1 050/1 175 1 900
850 2 400 1 360 2 900 3 400
b
2 200
II 420 1 175/1 300 2 200
950 2 900 1 425 3 100 3 600
b
2 400
1 300/1 425 1 050 2 600 3 400 1 575 3 600 4 200
1 175/1 300 950 2 200 2 900
1 615 3 700 4 300
b
2 400
1 300/1 425 1 050 2 600 3 400 1 680 3 900 4 600
1 425/1 550 1 175 3 100 4 100 1 763 4 200 5 000
1 675/1 800 1 300 3 600 4 800 2 210 6 100 7 400
800 1 800/1 950 1 425 4 200 5 600 2 423 7 200 9 000
1 950/2 100 1 550 4 900 6 400 2 480 7 600 9 400

– 6 – 61936-1 Amend.1 © IEC:2014
Highest Rated Rated Rated
voltage for lightning switching Minimum switching Minimum
installation impulse impulse phase-to-earth impulse phase-to-phase
withstand withstand clearance withstand clearance
a
voltage voltage voltage
Voltage
U U U
U
p s s
m
Conductor Rod Conductor Rod
range
Phase-to- Phase-to-
1,2/50 µs – – – –
r.m.s.
earth phase
(peak value) structure structure conductor conductor
250/2 500 µs 250/2 500 µs
parallel
(peak value) (peak value)
N
kV kV kV mm kV mm
c
1 950/2 100 1 425 4 200 5 600 - - -
d d
2 100/2 250 1 550 4 900 6 400 2 635 8 400 10 000
1 100
d d d d
2 250/2 400 1 675 5 600 7 400 2 764 9 100 10 900
d d d d
2 400/2 550 1 800 6 300 8 300 2 880 9 800 11 600
d d d d
2 100/2 250 1 675 5 600 7 400 2 848 9 600 11 400
1 200 d d d d
2 250/2 400 1 800 6 300 8 300 2 970 10 300 12 300
d d d d
2 550/2 700 1 950 7 200 9 500 3 120 11 200 13 300
a
The rated lightning impulse is applicable phase-to-phase and phase-to-earth.
b
Minimum clearance required for upper value of rated lightning impulse withstand voltage.
c
This value is only applicable to the phase-to-earth insulation of single phase equipment not exposed to air.
d
Tentative values still under consideration.

6.2.1 Switching devices
Modify the fifth paragraph of this subclause as follows:
Where specified by the user, interlocking devices and/or locking facilities shall be installed to
provide a safeguard against inappropriate operation.
6.2.9.5 Installation of cables
Add the following new item h) after g):
h) if single-core cables are laid through reinforced ceilings and walls the possibility of heating
the steel reinforcing bars shall be considered. If necessary, suitable structural measures
to limit the heating shall be determined.
6.2.10 Conductors and accessories
Add the following new paragraph after the first paragraph:
Covered conductors shall be treated as bare conductors.
Add the following paragraph after the note:
Provision shall be made to avoid possible resonant oscillation of tubular busbars caused by
wind.
6.2.11 Rotating electrical machines
Replace the second paragraph of this subclause with the following:
The degree of protection of the equipment against the ingress of objects, dust and water shall
be chosen in accordance with the climatic and environmental conditions at the site of

61936-1 Amend.1 © IEC:2014 – 7 –
installation. Hazardous parts of the machine shall be protected against accidental contact by
persons. The degree of protection shall be defined in accordance with IEC 60529.
7.2.1 Protective barrier clearances
Replace the existing text of this subclause with the following:
Within an installation, the following minimum protective clearances shall be maintained
between live parts and the internal surface of any protective barrier (see Figure 1):
– for solid walls, without openings, with a minimum height of 1 800 mm, the minimum
protective barrier clearance is B = N;
– for wire meshes, screens or solid walls with openings, with a minimum height of 1 800 mm
and a degree of protection of IPXXB (see IEC 60529), the minimum protective barrier
clearance is B = N + 80 mm.
NOTE The degree IPXXB ensures protection against access to hazardous parts with fingers.
For non-rigid protective barriers and wire meshes, the clearance values shall be increased to
take into account any possible displacement of the protective barrier or mesh.
7.2.6 External fences or walls and access doors
Add the following note after the last paragraph:
NOTE The use of metal mat fences with a mesh size of 50 mm x 200 mm (width x height) is applicable if the
design of fencing prevents unauthorized entrance.
7.4.2.4 Earthing
Modify the first sentence of the second paragraph as follows:
The three enclosures of a single-phase type GIS shall be bonded together with short
connections and earthed at least at the end of the enclosure of the outgoing and incoming
feeders.
Figure 1 – Protection against direct contact by protective barriers/protective obstacles
within closed electrical operating areas
Replace the existing Figure 1 with the following new Figure 1:

– 8 – 61936-1 Amend.1 © IEC:2014

Protective obstacle Protective barrier
N N
Accessible surface
B = N Solid walls without openings
Indoor:  O = N + 200 (500 min.)
Outdoor :  O = N + 300 (600 min.)
2 B = N + 80 Wire mesh / Screen
-IPXXB
Non-accessible surface
Barrier less than 1 800
or rails, chains, ropes inside a barrier or obstacle

IEC  0217/14
Dimensions in millimetres
Key
N Minimum clearance
O Obstacle clearance
B Barrier clearance
Figure 1 – Protection against direct contact by protective barriers/protective
obstacles within closed electrical operating areas
Figure 2 – Boundary distances and minimum height at the external fence/wall
Replace the existing Figure 2 with the following new Figure 2:
H = N + 2 250 (2 500 min.)
2 250
1 200 min.
1 400 max.
1 800 min.
H = N + 2 250 (2 500 min.)
61936-1 Amend.1 © IEC:2014 – 9 –
N
Area without
live parts
and insulators
Accessible
surface
C = N + 1 000 Solid walls
E = N + 1 500 Wire mesh / Screens

IEC  0218/14
Dimensions in millimetres
Key
N  Minimum clearance
H '  Minimum clearance of live parts above accessible surface at the external fence
a  If this distance to live parts is les s than H , protection by barriers or obstacles s hall be provided
b If this dis tance is smaller than 2 250 mm, protection by barriers or obstacles s hall be provided
Figure 2 – Boundary distances and minimum height at the external fence/wall
8.4.2 Devices to prevent reclosing of isolating devices
Replace, in the second paragraph of this subclause, the words “an approved tool” with “a
suitable tool”.
8.4.3 Devices for determining the de-energized state
Replace the third paragraph of this subclause with the following:
Either fixed equipment (see IEC 62271-206) or portable devices (see the IEC 61243 series)
can be used to meet this requirement.
8.5 Protection from danger resulting from arc fault
Replace item i) of this subclause with the following:
i) Prevention of re-energization by use of non-resettable devices which detect internal
equipment faults, enable pressure relief and provide an external indication.
U > 52 kV: H’ = N + 4 500 (6 000 min.)
m
U   52 kV: H’ = 4 300
m
1 800 min.
b
a a
– 10 – 61936-1 Amend.1 © IEC:2014
8.7.1 General
Replace the third dashed item in item a) with the following:
– fire barriers (e.g. fire walls with fire resistance of minimum 60 minutes),
Replace the text in iv) with the following:
iv) non-combustible materials
8.7.2 Transformers, reactors
Replace the first sentence in the last paragraph of this subclause with the following:
The same applies to individual sumps which are connected to the catchment tanks of other
transformers; crushed stone layers, fire protection gratings or pipes filled with fluid can, for
example, be used for this purpose.
8.7.2.1 Outdoor installations
Replace the existing text of this subclause with the following:
The layout of an outdoor installation shall be such that burning of a transformer with a liquid
volume of more than 1 000 l will not cause a fire hazard to other transformers or objects, with
the exception of those directly associated with the transformer. For this purpose, adequate
clearances, G , G shall be necessary. Guide values are given in Table 3. Where
1 2
transformers with a liquid volume below 1 000 l are installed near walls of combustible
material, special fire precautions may be necessary, depending on the nature and the use of
the building.
If automatically activated fire extinguishing equipment is installed, the clearances G /G can
1 2
be reduced.
The reduction of distances G /G shall be agreed upon between the user and the supplier.
1 2
If it is not possible to allow for adequate clearance as indicated in Table 3, fire-resistant
separating walls with the following dimensions shall be provided:
a) between transformers (see Figure 6) separating walls. For example EI 60:
– height: top of the expansion chamber (if any), otherwise the top of the transformer
tank;
– length: width or length of the sump (in the case of a dry-type transformer, the width or
length of the transformer, depending upon the direction of the transformer);
b) between transformers and buildings separating walls. For example EI 60; if additional fire
separating wall is not provided, fire rating of the building wall should be increased, for
example REI 90 (see Figure 7).
NOTE 1 REI represents the bearing system (wall) whereas EI represents the non-load bearing system (wall)
where R is the load bearing capacity, E is the fire integrity, I is the thermal insulation and 60/90 refers to fire
resistance duration in minutes.
NOTE 2 Definitions of fire resistance are given in EN 13501-2[37].
Table 3 – Guide values for outdoor transformer clearances
Replace the existing Table 3 with the following new Table 3:

61936-1 Amend.1 © IEC:2014 – 11 –
Table 3 – Guide values for outdoor transformer clearances
Transformer type Liquid volume Clearance G to other Clearance G to building
1 2
transformers or building surface of combustible
surface of non- material
combustible material
l m m
Oil insulated transformers (O)
3 7,5
1 000 <.< 2 000
2 000 ≤.< 20 000 5 10
10 20
20 000 ≤.< 45 000
≥ 45 000 15 30
Less flammable liquid
insulated transformers (K) 1 000 <.< 3 800 1,5 7,5
without enhanced protection
≥ 3 800 4,5 15
Less flammable liquid Clearance G to building surface or adjacent transformers
insulated transformers (K)
Horizontal Vertical
with enhanced protection
m m
0,9 1,5
Dry-type transformers (A) Fire behaviour class Clearance G to building surface or
adjacent transformers
Horizontal Vertical
m m
F0 1,5 3,0
F1 None None
NOTE 1 Enhanced protection means
– tank rupture strength,
– tank pressure relief,
– low-current fault protection,
– high-current fault protection.
For an example of enhanced protection, see Factory Mutual Global standard 3990 [33], or equivalent.
NOTE 2 Sufficient space should be allowed for periodic cleaning of resin-encapsulated transformer windings, in
order to prevent possible electrical faults and fire hazard caused by deposited atmospheric pollution.
NOTE 3 Non-combustible materials may be chosen in accordance to EN 13501-1[36].

Table 4 – Minimum requirements for the installation of indoor transformers
Replace, in Note 1 to Table 4, the words “time in minutes” with “fire resistance duration in
minutes”.
– 12 – 61936-1 Amend.1 © IEC:2014
Add, after Note 1 to this table, the following new Note 2 and renumber the existing Notes 2
and 3 as Notes 3 and 4 respectively.
NOTE 2 Definitions of fire resistance are given in EN 13501-2[37].
8.8.1.3 Containment for outdoor equipment
Add the following paragraph after the last dashed item of this subclause:
For outdoor installations, it is recommended that the length and width of the sump be equal to
the length and width of the transformer plus 20 % of the distance between the highest point of
the transformer (including the conservator) and the upper level of the containment on each
side.
Delete Note 2.
Replace the text of the existing Note 3 with the following, and renumber the existing Note 3 as
Note 2:
NOTE 2 IEEE 980 recommends that the spill containment extends a minimum 1 500 mm beyond any liquid-filled
part of the equipment.
8.8.2 SF leakage
Delete, in the first sentence of the third paragraph, the comma between the words "sufficient"
and "if".
Figure 7 – Fire protection between transformer and building
Replace the existing Figure 7 with two new sub-figures as follows:

61936-1 Amend.1 © IEC:2014 – 13 –
Outdoor Indoor
G
< G
G
G
G
G
IEC  0219/14
Figure 7a) Fire protection between transformer
and building surface of non-combustible material
c b a b c a b
– 14 – 61936-1 Amend.1 © IEC:2014
Outdoor Indoor
G
G
< G > G
2 1
G
G
G
G
IEC  0220/14
Figure 7b) Fire protection between transformer
and building surface of combustible material
Key
For Clearances G and G see Table 3
1 2
Sector a The wall in this area shall be designed with a minimum fire resistance of 90 min (REI 90)
Sector b The wall in this area shall be designed with non combustible materials
Sector c No fire protection requirements
NOTE Due to the risk of vertical fire spread sector c applies only in the horizontal direction.
Figure 7 – Fire protection between transformer and building
b
c b c b
61936-1 Amend.1 © IEC:2014 – 15 –
Figure 8 – Sump with integrated catchment tank
Replace, in the Key to this figure, the text corresponding to b with the following:
b For information concerning fire protection gratings or fire blocking outlets, see 8.7.2
Figure 9 – Sump with separate catchment tank
Replace, in the Key to this figure, the text corresponding to b with the following:
b For information concerning fire protection gratings or fire blocking outlets, see 8.7.2
Figure 10 – Sump with integrated common catchment tank
Replace, in the Key to this figure, the text corresponding to b with the following:
b For information concerning fire protection gratings or fire blocking outlets, see 8.7.2
9.6.5 Measures related to the selection of equipment
Replace the text of item e) with the following:
e) Adequate earthing for power frequency and transient effects at the GIS/air-bushings and
GIS-tubes. This is achieved by multiple connections between the enclosure and the
building wall (to the reinforcement grid or metallic cladding) and multiple connections
between the wall and earthing system.
10.2.1 Safety criteria
Add the following text after the second paragraph:
The earthing design parameters (relevant fundamental requirements, e.g. fault current, fault
duration) shall be agreed between user and supplier.
10.3.1 General
Modify item e) as follows:
e) determine the current flowing into earth from the earthing system, based on earth fault
current;
Delete item m) from the list.
12 Operation and maintenance manual
Add the following new text after the first paragraph:
For the preparation of manuals and instructions, IEC 82079-1 applies.
Annex D – Earthing system design flow chart
Replace the existing flow chart with the following:

– 16 – 61936-1 Amend.1 © IEC:2014
IEC  0221/14
E.2 Shield wires
Replace, in the second paragraph of this subclause, the words “of less than” with “of less than
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