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Cutler Hammer Panelboards

3140 Views 10 Replies 5 Participants Last post by  yelirAmme, 
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We just installed a brand new cutler hammer panelboard at work this week and when wiring it up we saw the feeds for the panel are the first three circuit breaker slots on the left side, which isn't abnormal around here. Now my question is, on the other side opposite the main breaker there is no way to install breakers because where the connections normally are, there are rivets going throught the holes. Why is that? One of the guys I work with was recently working at a hospital and was told by the engineer not to use the spaces opposite the feed, but wasnt told why he couldnt. Does anyone know why you can not install breakers opposite the main feeds anymore? Is this in the code now? we've been discussing it at work and no one knows why.
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G

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#2 ·
First off, welcome to the nuthouse. :thumbup::D:jester:

The reason those spaces are not useable is that each bus stab or finger has a certain ampacity, and those opposite the main are usually loaded to their max ampacity at the breaker's rating. Thus they cannot be used for other circuits.
 
gold

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#5 ·
I keep hearing people ask various questions about breakers opposite the main. What advantage is there to back feeding a sub on a new install? Besides maybe availability or cost.

Not to hijack the thread but ...
 
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#6 ·
gold said:
I keep hearing people ask various questions about breakers opposite the main. What advantage is there to back feeding a sub on a new install? Besides maybe availability or cost.

Not to hijack the thread but ...
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Well breakers opposite the main and backfeeding a sub are two different animals...:D

But as for the backfeeding a main in a sub, it is a matter of either preference, or to keep within the six throws rule....I did that in my garage subpanel in a house I owned..I had several branch circuits in the garage and just wanted a main there "because."
 
Dennis Alwon

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#7 ·
I only back feed a panel when it is in a separate building being fed with 60 amps. Most residential panels will not allow larger than 125 amps on the bus bar anyway. I think the bus connection at those points will not handle the higher load.
 
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T

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#10 ·
how many spaces were available below the main... a lot of times they'll put like a 48 'space' interior in a panel, use the top 6 for the main(3 breaker 3 rivited closed), and leave the other 42 to make a 42 space panel
 
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