Work Clearances

DOE-HDBK-1092-2004

9.9

WORKING CLEARANCES

Clear working space and headroom shall meet the NEC requirements (see Figs. 9-4 and 9-5).

The clear working space and passageways to this space should not be used for storage. At

least one entrance of sufficient area shall be provided to give access to working space above

electrical equipment. For example, 24 inches may be sufficient in depth and 30 inches in width

with 6 foot height

Walls or other

No access required. No

obstructions

minimum space

requirement.

Distance as determined by Fig. 2-4

of Section 2, when power is on,

Cabinet doors

24" when power is off.

must open at least

90 or the door

must be removed.

Access required - with

power off, 24"; with

power on, refer to Fig.

3 Bay

2-4 of Section 2.

Equipment

Rack

3 Bay

Equipment

Rack

Passageway

24" min.

Open Chassis

Distance as determined by Figure 2-4 of Section 2. If

a chassis is open, measurement is made from the front

of the chassis to the wall or obstruction.

Operator Space

Fig. 9-4. Top View of Equipment Layout in a Room (Drawing is not to scale)

While maintenance, repair or calibration are being performed, personnel should identify clear

working spaces via suitable means such as "Danger" or "Caution" barrier tape, or barricades to

keep other personnel from entering the clear working spaces.

9-14