PowerPact B-frame Clearances, UL Standard
For all types of PowerPact B-frame circuit breakers that use uninsulated power connections (for example, busbars, spreaders, or uninsulated compression lugs), the minimum clearance distance between the enclosure backplate (grounded metal) and uninsulated power connections is shown below.
When using uninsulated connectors be sure to maintain the proper clearance between live parts and the grounded metallic back pan or use the insulation screen.
Minimum Enclosure Dimensions |
|
Standard (80%) |
100% Rated |
14.6 x 8.5 x 3.16
in. |
18.13 x 8.63 x 4.13 in. |
Minimum Clearance Dimensions to Enclosure or Any Grounded Metal |
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Operating voltage V < 690 Vac, 250 Vdc |
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For devices equipped with: |
Clearance |
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Between devices |
Between device and sheet metal |
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Painted sheet metal |
Bare sheet metal |
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A1 |
A2 |
B |
A1 |
A2 |
B |
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No terminal accessories |
0 |
30 mm |
5 mm |
0 |
40 mm |
5 mm |
5 mm |
Interphase barriers |
0 |
0 |
0 |
0 |
0 |
0 |
5 mm |
Long terminal shields |
0 |
0 |
0 |
0 |
0 |
0 |
5 mm |
Minimum Clearances to Bare Busbars |
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Operating voltage V ≤ 690 Vac, 250 Vdc |
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Clearances to live bare busbars * |
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Spacing E ≤ 60 mm (2.36 in.) |
Spacing E > 60 mm (2.36 in.) |
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D1 |
D2 |
D1 |
D2 |
200 mm |
100 mm |
120 mm |
60
mm |
|
Exposed Conductor Clearance
An insulating screen or long terminal shield is required if C < 12.7 mm (< 0.5 in.) if voltage is ≥ 300 Vac.