External Conductor in Switchboard section

[smarteng]

Hello Everybody,

We have a switchboard 480V, 1600A. One of the sections with un-insulated bus bars of the switchboard has external conductors entering from bottom and existing from the side. Those conductors are also have spliced inside the switchboard section. Conductor feeds circuits which are completely unrelated to the switchboard. Is this acceptable by NEC/Codes and is it safe to have external conductors in a switchboard section with un-insulated bus bars. Please advise.

Thank you.

 

[xptpcrewx]

Hello Everybody,

We have a switchboard 480V, 1600A. One of the sections with un-insulated bus bars of the switchboard has external conductors entering from bottom and existing from the side. Those conductors are also have spliced inside the switchboard section. Conductor feeds circuits which are completely unrelated to the switchboard. Is this acceptable by NEC/Codes and is it safe to have external conductors in a switchboard section with un-insulated bus bars. Please advise.

Thank you.

I don’t believe it’s prohibited anywhere but you would still need to follow the rules that apply. For example, conductor insulation type, clearances for conductors entering bus enclosures, field identification etc.

Note: Running unrelated circuits through equipment is not the smartest thing. If you have a failure in one circuit you can potentially induce that failure onto the other non related circuit(s). Similarly, to perform work/maintenance on one a piece of equipment would require de-energizing both circuits. Lastly, this can introduce confusion.

 

[texie]

Hello Everybody,

We have a switchboard 480V, 1600A. One of the sections with un-insulated bus bars of the switchboard has external conductors entering from bottom and existing from the side. Those conductors are also have spliced inside the switchboard section. Conductor feeds circuits which are completely unrelated to the switchboard. Is this acceptable by NEC/Codes and is it safe to have external conductors in a switchboard section with un-insulated bus bars. Please advise.

Thank you.

See 408.3 A (3).

 

[xptpcrewx]

See 408.3 A (3).

Good point. Missed that one.

 

[smarteng]

See 408.3 A (3).

Thank you so much sir. So I understand it is restricted by this code. What is your opinion about 312.8(A). 312.8(A) allows enclosure to have external cable, splices etc as long as conditions 1,2 and 3 are met.

 

[smarteng]

I don’t believe it’s prohibited anywhere but you would still need to follow the rules that apply. For example, conductor insulation type, clearances for conductors entering bus enclosures, field identification etc.

Note: Running unrelated circuits through equipment is not the smartest thing. If you have a failure in one circuit you can potentially induce that failure onto the other non related circuit(s). Similarly, to perform work/maintenance on one a piece of equipment would require de-energizing both circuits. Lastly, this can introduce confusion.

Thank you so much.