Buss Size Identification

[elenTemp]

Hi, I am looking at panelboards and I want to determine the bus size. How do I do this?

Thank you,
Master Electrician Elen Temp

 

[jim dungar]

Hi, I am looking at panelboards and I want to determine the bus size. How do I do this?

Thank you,
Master Electrician Elen Temp

Look at the panel label.

Panel bussing is not determined by physical size. UL allows busses, and the enclosures they are mounted in, to be sized by heat transfer.

 

[Tulsa Electrician]

Here is an example.

 

[Tulsa Electrician]

The pic did not load try again

 

[rambojoe]

Hi, I am looking at panelboards and I want to determine the bus size. How do I do this?

Thank you,
Master Electrician Elen Temp

How is this a good question from a master electrician?

 

[elenTemp]

How is this a good question from a master elect

How is this a good question from a master electrician?

Rambojoe how long have worked as a wireman?
Also, what has been your favorite project?

 

[Jraef]

As Jim said, there is no simple way to determine the bus size just by looking at it. Bus ampacity is a function of heat rise in the given enclosure, so the same cross sectional area in a different mounting arrangement may pass the heat rise requirements that would have needed a higher cross section in another arrangement. As one engineer put it to me, "If it passes, it's good, if not, we add some spacing and/or material and test again."