UFC 3 -520-01
June 10, 2002
8-1.2.3 Working Space. Provide working space no t less than indicated in Table 8 -1
in the direction of access to energized parts operating at 600 volts or less that require
examination, adjustment, servicing, or maintenance while energized. In addition to the
dimensions shown in Table 8 -1, provide a wo rking space in front of the electric
equipment to be the width of the equipment or 0.9 meters (3 feet), whichever is greater.
Measure distances from the energized parts if such are exposed or from the enclosure
front or opening if such are enclosed. Conc rete, brick, or tile walls can be considered
grounded. Working space is not required in back of assemblies, such as dead-front
switchboards or MCCs, provided that there are no renewable or adjustable parts on the
back and all connections are accessible from locations other than the back.
Table 8-1. Working Space Clearances 600 Volts and Below
Clear
Clear
Voltage
Condition
Distance
Distance
to Ground
(feet)
(meters)
0 150
All.
3
0.9
151 600
Exposed energized parts on one side and no
3
0.9
energized or g rounded parts on the other side of the
working space, or exposed energized parts on both
sides effectively guarded by suitable wood or other
insulating materials. Insulated wire or insulated bus
bars operating at not over 300 volts will not be
considered energized parts . Condition 1 of NEC
Table 110.26(A)(1) (2002 Edition) .
151 600
Exposed energized parts on one side and grounded
3.5
1.0
parts on the other side. Concrete, brick, or tile walls
can be considered grounded. Condition 2 of NEC
Table 110.26(A)(1) (2002 Edition) .
151 600
Exposed energized parts on both sides of the work
4
1.2
space (not guarded). Condition 3 of NEC Table
110.26(A)(1) (2002 Edition) .
8-1.2.4 Headroom Working Space. The headroom of working spaces about
switchboards or control centers should not be less than 2.1 meters (7 feet). Headroom
is defined as the distance from the floor to the ceiling. The NEC headroom requirement
is 2 meters (6.5 feet); in this instance, greater headroom space is recommended
whenever possible. If the electrical equipment exceeds 2 meters (6.5 feet), provide
minimum headroom not less than the height of the equipment.
8-1.2.5 Clearance of Other Equipment. Within the headroom working space height
requirement of paragraph 8 -1.2.4, other equipment associated with the electrical
8-2
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