Neutral bus bar

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Such terminal bars do not have a current rating. If the wire fits, you are good. Now if you retrofit a lug to that bar that is not supplied/approved by the bar maker, you could be called on a 110.3 (B).
 
electrofelon said:
Such terminal bars do not have a current rating. If the wire fits, you are good. Now if you retrofit a lug to that bar that is not supplied/approved by the bar maker, you could be called on a 110.3 (B).
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Wouldn't a neutral bus bar in several sections of switchgear need to be large enough to carry the load?

Itsbeanie said:
What is the amperage of a neutral bus bar that is .5" × 4" I have searched through the NEC book and cannot find the formula anywhere.
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Take a look here:

http://forums.mikeholt.com/showthread.php?t=189514&highlight=copper
 
Code minimum for a busbar

Listed connections to aluminum or copper busbars not
smaller than 6 mm thick × 50 mm wide (1∕4 in. thick × 2 in.
wide) and of sufficient length to accommodate the
number of terminations necessary for the installation. If
aluminum busbars are used, the installation shall also
comply with 250.64(A).
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electrofelon said:
Rob, I am aware of those common 750/1000 figures for ampacity of busbars, bit IIRC the nec doesn't really have provisions for allowing us to make/use/calculate the ampacity of a busbar right?
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I agree that the NEC doesn't answer the OP's question but doesn't the neutral bus need to be sized to carry the load? Now where that requirement is located is escaping me at the moment. :)
 
Itsbeanie said:
What is the amperage of a neutral bus bar that is .5" × 4" I have searched through the NEC book and cannot find the formula anywhere.
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As a rough and ready rule of thumb we worked on 1000A per square inch.
It's pessimistic so, to that extent safe I suppose.

Horizontal, vertical, free air, still air......
 
Itsbeanie said:
This question was asked on a master electrician pre-test
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Did you look at the link in post #4? The NYC electrical code mentions 1000 amp/sq inch for copper. If you look at the end of the bus bar in your question you have .5"*4"= 2 sq inches = 2000 amps.
 
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