Clearance Requirement for Conductor Entering Bus Enclosure

Sept. 25, 2014
Article 408 covers switchboards and panelboards.

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.

Voice your opinion!

To join the conversation, and become an exclusive member of EC&M, create an account today!

Sponsored Recommendations

Electrical Conduit Comparison Chart

CHAMPION FIBERGLASS electrical conduit is a lightweight, durable option that provides lasting savings when compared to other materials. Compare electrical conduit types including...

Fiberglass Electrical Conduit Chemical Resistance Chart

This information is provided solely as a guide since it is impossible to anticipate all individual site conditions. For specific applications which are not covered in this guide...

Considerations for Direct Burial Conduit

Installation type plays a key role in the type of conduit selected for electrical systems in industrial construction projects. Above ground, below ground, direct buried, encased...

How to Calculate Labor Costs

Most important to accurately estimating labor costs is knowing the approximate hours required for project completion. Learn how to calculate electrical labor cost.