Publication 2100-IN012B-EN-P - April 2005
Final Checklist Before Energizing 3-7
Table 3.B Spacing Requirements within Motor Control Center Units
(1)
,
(2)
,
(3)
Voltage
involved
Minimum spacing, inch (mm)
Between uninsulated live parts of opposite
polarity and between an uninsulated live
part and an exposed or uninsulated dead
metal part other than the enclosure
Between uninsulated live
parts and the walls of a metal
enclosure
(3)
, including
fittings for conduit or
armored cable
Through air Over surface Shortest distance
125 or less
1/8” (3.2mm)
(2)
1/4” (6.4mm) 1/2” (12.7mm)
126 – 250 1/4” (6.4mm) 3/8” (9.5mm) 1/2” (12.7mm)
251 – 600 3/8” (9.5mm) 1/2” (12.7mm) 1/2” (12.7mm)
(1)
Reference Underwriters Laboratories, Inc. Standards for Motor Control Centers, UL 845, Tables 16.1 and 16.3.
(2)
The spacing between wiring terminals of opposite polarity shall not be less than 1/4” (6.4 mm) if the terminals are in the same
plane.
(3)
The enclosure refers to the section enclosure.
NOTE – A metal piece attached to the enclosure is considered a part of the enclosure for the purpose of this note if deformation of the
enclosure is likely to reduce the spacing between the metal piece and a live part.
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