COD E IN F O C U S BY CHARLES R. MILLER
The dimension for height of working space for equipment operating at
600 volts (V), nominal, or less to ground
and likely to require examination,
adjustment, servicing or maintenance
while energized shall comply with the
110. 26(A)( 3). The work space shall be
clear and extend from the grade, floor
or platform to a height of 6½ feet or the
height of the equipment, whichever is
greater. The electrical equipment itself
may have a height that is less than 6½
feet, but if it is mounted so the top of the
equipment is higher than 6½ feet, the
minimum working space height shall be
the equipment height.
For example, a panelboard is installed
next to a disconnect (safety) switch on a
concrete block wall. The actual panel-
board height is 5 feet, 4 inches, but it is
mounted 20 inches from the floor. The
top of the panelboard is 84 inches ( 7 feet)
above the floor. In this installation, no
circuit breaker (in its highest position) is
more than 6 feet, 7 inches above the floor.
Therefore, this installation complies
with 404.8(A). The top of the disconnect
switch is only 72 inches ( 6 feet) above the
floor. Since the top of the panelboard is
more than 6½ feet above the floor, the
minimum working space height required
for this panelboard is the height of the
panelboard. The minimum working
space height required for this disconnect
switch is 6½ feet (see Figure 1).
The second sentence in 110. 26(A)( 3)
states that, within this section’s height
ONE WAY TO HELP SAFEGUARD PEOPLE from hazards arising from electricity
use is to ensure there is sufficient working space in front of and around electrical
equipment. Article 110. 26 in the National Electrical Code (NEC) contains specifications for the working space dimensions required around all electrical equipment.
This working space also shall be maintained to permit ready and safe operation and
maintenance of such equipment. The minimum dimensions for depth, width and
height of working space are covered in 110. 26(A)( 1), (A)( 2) and (A)( 3).
General Installation Requirements, Part XX
FIGURE 1 WORKING SPACE HEIGHT
The electrical equipment itself may have a height that is less than 6½ feet, but if it is
mounted so the top of the equipment is higher than 6½ feet, the minimum working
space height shall be the height of the equipment.
space height for this
panelboard is 7 feet. Minimum working space
height for this disconnect
switch is 6 feet, 6 inches.
floor is 7 feet. The height of
the floor is
FIGURE 2 ASSOCIATED
Within the working space height
requirements of 110. 26(A)( 3), other
equipment that is associated with
the electrical installation and is
located above or below the electrical
equipment is not permitted to extend
more than 6 inches beyond the front of
the electrical equipment.
or below electrical
space must be
The trough (wireway) extends
6 inches beyond the front of these
panelboards, which is the
maximum distance permitted.
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