PART 3 SECTION 16 REQUIREMENTS FOR SPECIAL INSTALLATIONS OR

LOCATIONS —
OPERATING OR MAINTENANCE GANGWAYS

1 SCOPE
The requirements of this part of NEC apply to basic protection and other aspects in
restricted access areas with switchgear and controlgear assemblies, including
requirements for operating or maintenance gangways.

2 REFERENCES
The Indian Standards given below contain provisions which through reference in this text, constitute
provision of this standard. At the time of publication, the editions indicated were valid. All standards
are subject to revision, and parties to agreements based on this standard are encouraged to investigate
the possibility of applying the most recent editions of the standards.

ISNo. Title

IS 732 : 2019 Code of practice for electrical wiring installations

3 ASSESSMENT OF GENERAL CHARACTERISTICS

For purposes supplies and structure, please refer to relevant items under4.1 of IS 732.
Additional requirements have been mentioned against each item below.
Add the following requirements:
For restricted access areas the following apply:
a) restricted access areas shall be clearly and visibly marked by appropriate
signs;
b) unauthorized persons shall not have access to restricted access areas; and
c) door(s) provided for closed restricted access areas shall allow easy evacuation
to the outside by opening without the use of a key, tool or any other device
which is not part of the opening mechanism.

3.1Replace the paragraph with the following requirements:

In restricted access areas where it is not reasonably practicable to provide protective
measures for basic protection (protection against direct contact) in accordance with IS
732 Clause 4.2, minimum distances are required.
NOTES:
1 See4.1.5.5 of IS 732 for assessment of general characteristics when deciding to use
this method of protection.
2 In cases of protective devices with high ratings, such as a large circuit-breaker,
greater distances may be necessary to permit withdrawal of the device.
3.1.1Where the gangway has unprotected live parts arranged on one side only (see
Fig.1), the minimum distances shall be:
a) width of gangway between the wall and live parts 900 mm;
b) free passage in front of controls (handles, etc.) 700 mm; and
c) height of live parts above the floor 2 500 mm.

Dimensions in millimetres
Live parts

2 500

700 900

The 2500 mm height above the floor given as the minimum distance to live parts applies
only in the gangway where it is possible for persons to stand or walk.
FIG. 1 GANGWAYS IN INSTALLATIONS WITH LIVE PARTS ON ONE SIDE
3.1.2Where the gangway has live parts on both sides (see Figure 2), the minimum
distances shall be:
a) width of gangway between live parts 1 300 mm;
b) minimum distance between the front of the handle and the
live parts on the opposite side of the gangway 1 100 mm;
c) minimum free passage in front of controls (handles, isolation
position of circuit-breakers, etc.) 900 mm;
d) height of live parts above the floor 2 500 mm.
 Dimensions in millimetres
Live parts

2 500

Circuit breaker in the

position “isolation”

1 300 900

1 100

1 100

The 2500 mm height above the floor given as the minimum distance to live parts applies
only in the gangway where it is possible for persons to stand or walk.
FIG. 2 GANGWAYS IN INSTALLATIONS WITH LIVE PARTS ON BOTH
SIDES
4 ACCESSIBILITY
For accessibility, please refer relevant items under 5 of IS732. Additional requirements
have been mentioned against each item below.
Add the following paragraphs:

4.1 Requirements for Operating and Maintenance Gangways

The width of gangways and access areas shall be adequate for work, operational access,
emergency access, emergency evacuation and for the movement of equipment.

Gangways shall permit equipment doors or hinged panels to be opened to at least 90°(see
also Annex A,A-1).

4.1.1 Restricted Access Areas Where the Protective Measure of Barriers or

Enclosures Applies
Where the protective measure is provided by barriers or enclosures in accordance with
4.2 of IS 732 he following minimum distances apply (seeFig.3):
a) width of gangways with barriers or enclosures between switch handles 600 mm
and circuit-breakers in position “isolation” orswitch handles and the wall
b) width of gangway between barriers or enclosures and other barriers or700 mm
enclosures, orbarriers or enclosures and the wall
c) height of panelling above the floor 2 000 mm;
d) height of live parts above the floor 2 500 mm.
NOTE — Where additional workspace is needed for example, special switchgear and
controlgear assemblies, larger dimensions may be required.
Dimensions in millimetres
Live parts

Panelling Barriers or
enclosures

Circuit-breaker

2 500
in the position
“isolation”
2 000

700 700 600 600

700

FIG. 3 GANGWAYS IN INSTALLATIONS WHERE THE PROTECTIVE

MEASURE OF BARRIERS OR ENCLOSURES APPLIES
NOTE— The above dimensions apply after all parts of the panelling have been
mounted and closed and to circuit-breakers in the position”isolation".
4.1.2 Restricted Access Areas Where the Protective Measure of Obstacles Applies
Where the protective measure of obstacles applies in accordance with 4.2 of IS 732 the
following minimum distances apply (seeFig.4):
a) width of gangway between obstacles and switch handles, or 700 mm
obstacles and the wall, or switch handles and the wall
b) height of panelling above the floor 2 000 mm
c) height of live parts above the floor 2 500 mm
 Dimensions in millimetres

Live parts

Panelling
Obstacles

Circuit breaker

2 500
in the position
“isolation”
2 000

700 700 700 700

FIG. 4 GANGWAYS IN INSTALLATIONS WHERE THE PROTECTIVE

MEASURE OF OBSTACLES APPLIES
NOTE — The above dimensions apply after all parts of the panelling have been
mounted and closed and to circuit-breakers in the position”isolation”.
4.1.3 Access of Gangways
Gangways longer than 10 m shall be accessible from both ends.
NOTES:
1 This may be accomplished by placement of the equipment a minimum of 700 mm
from the end walls (see Fig.5) or by providing an access door, if needed, on the opposite
end wall.
Closed restricted access areas with a length exceeding 20 m shall be accessible by doors from
both ends.
2 For closed restricted access areas with a length exceeding 6 m, accessibility from
both ends is recommended.
 Dimensions in millimetres

≥700

10 000

≥20 000

≥700 ≥700

≥10 000

FIG. 5 EXAMPLES OF POSITIONING OF DOORS IN LONG CLOSED

RESTRICTED ACCESS AREAS
 ANNEX A
(Normative)

ADDITIONAL REQUIREMENTS
FOR CLOSED RESTRICTED
ACCESS AREAS

A-1 EVACUATION
To permit easy evacuation, the doors of any equipment inside the location shall close in
the direction of the evacuation route. Gangways shall permit e quipment doors or hinged
panels to be opened to a minimum of 90°(see Fig.eA-1).
NOTE —Figures A-1, A-2 and A-3 show the minimum width of gangways and distances for
passing in case of evacuation.

Dimensions in millimetres

Minimum Evacuation route direction

passing
width 600*)
1)
2)

*)A minimum width of 600 mm lies between the wall and the circuit-breaker in the
“fully withdrawn” position.
1) Circuit-breaker in the “completely extracted and isolated” position

2) Handles (for example, for controls or equipment)

FIG. A-1 MINIMUM PASSING WIDTH IN CASE OF EVACUATION – CASE 1

For doors which can be fixed in the open position or circuit-breakers or equipment which
are withdrawn fully for maintenance (position: completely extracted) a minimum
distance of 500 mm shall be provided between the door edge or circuit-
breaker/equipment edge and the opposite side of the gangway (see Fig.A-2and A-3).
NOTE — See Fig.A-3 for the minimum passing width in case of circuit-breaker in
position: completely extracted.
 Dimensions in millimetres

Minimum
Evacuation route direction
passing
width 500

*)

*) Hinged mounting rack

FIG. A-2 MINIMUM PASSING WIDTH IN CASE OF EVACUATION — CASE

2

Dimensions in millimetres

Minimum Evacuation route direction

passing
width 500*

1)

2)

*) A minimum width gangway of 500 mm shall be provided between the wall and the
circuit-breaker in the “fully withdrawn” position or the door which has been fixed in
the open position.
1) Completely withdrawn circuit-breaker
2) Door fixed in open position
FIG. A-3 MINIMUM PASSING WIDTH IN CASE OF EVACUATION —
CASE 3
Doors giving access to gangways in closed restricted access areas shall open outwards
(see Fig.5) and they shall have the following minimum dimensions:
a) width: 700 mm;
b) height: 2 000 mm.
minimum free passage is 1 200 mm.
 Annex B
(informative)

ADDITIONAL INFORMATION FOR CLOSED RESTRICTED

ACCESS AREAS

B-1 VENTILATION AND CONDITIONING

Closed restricted access areas should be either:
a) ventilated with the air being exhausted outdoors (naturally or mechanically), or
b) air-conditioned.
NOTES:
1 The ventilation is installed in order to prevent introduction of dust in the equipment.
Air conditioning should be used, where necessary, to ensure a suitable temperature is
maintained.
2 Switchgear and controlgear of distribution boards and accumulators are designed
for temperature ranges specified by the manufacturer.

B-2 CONSTRUCTION AND LIGHTING

Gangways should have a firm, even floor and should be provided with adequate lighting.

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