Clearance Requirement for Conductor Entering Bus Enclosure

Noninsulated busbars shall have a minimum space of ___ in. between the bottom of a switchboard enclosure and busbars or other obstructions.

a) 6
b) 8
c) 10
d) 12

See answer and applicable Code reference

The correct answer is: c) 10

Article 408 covers switchboards and panelboards. The clearance requirements for conductor entering bus enclosures can be found in Sec. 408.5. As noted in Table 408.5, noninsulated busbars shall maintain a minimum 10 in. spacing between the bottom of the enclosure and busbars, their supports, and other obstructions.


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