Cutler Hammer panels

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
One of our master electricians did some research and got confirmation of something I have long suspected. For Cutler-Hammer panels (and I suspect for others as well) they don't make differently rated busbars for every different panel. Specifically, and he got it in writing, all 150A - 225A CH panels have 225A rated busbars.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
And 100's probably have 125?

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I would assume so, but I have no confirmed info on the other panels.

This on the 200A panels is a game changer for us. We see CH 200A panels with 200A main breakers all the time; this changes the headroom on the bus from 40A to 70A.
 

jaggedben

Senior Member
All new panels or all past ones?

I think I'm going to have a hard time with AHJs if the panels don't say 225A on the label.

Also, are you specifically talking about CH panels? Or do you mean Cutler-Hammer branded BR panels, which started being branded as Eaton a few years ago? I don't see many CH panels.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
All new panels or all past ones?

I think I'm going to have a hard time with AHJs if the panels don't say 225A on the label.

Also, are you specifically talking about CH panels? Or do you mean Cutler-Hammer branded BR panels, which started being branded as Eaton a few years ago? I don't see many CH panels.
I'd advise getting in contact with CH for those questions. You'll need the documentation directly from them, anyway, to make your case with an AHJ. FWIW, it never made sense to me that they would use different buses for every panel rating.
 

KaBoom!

Inactive, Email Never Verified
Location
NJ
Murray breakers are the same as Siemens breakers other than the sticker and print. We know that, but it does not matter. The only thing that matters is what the listing says.
 

KaBoom!

Inactive, Email Never Verified
Location
NJ
Not sure how that applies to bus bar ampacity...?:?
It doesn't.

It applies to using something that you know is the same but not listed as such in that application.

Can you use a Murray breaker in a Siemens panel, even though they are the same? No.

Can you treat the busbar in a 150A panel as if it's a 225A panel even though it's the same? No.
 

macmikeman

Senior Member
I would assume so, but I have no confirmed info on the other panels.

This on the 200A panels is a game changer for us. We see CH 200A panels with 200A main breakers all the time; this changes the headroom on the bus from 40A to 70A.
Headroom on the bus? Photovoltaic load allowance? 20% of 225 is 45 amps 20% of 200 amps is 40 amps. I am not understanding the 70amps thing.
What am I missing please?
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
Headroom on the bus? Photovoltaic load allowance? 20% of 225 is 45 amps 20% of 200 amps is 40 amps. I am not understanding the 70amps thing.
What am I missing please?
The maximum combined overcurrent protection can not exceed 120% of the buss rating.
225 amp buss X 120% = 270 amps
200 amp utility breaker and 70 amp PV breaker
 
One of our master electricians did some research and got confirmation of something I have long suspected. For Cutler-Hammer panels (and I suspect for others as well) they don't make differently rated busbars for every different panel. Specifically, and he got it in writing, all 150A - 225A CH panels have 225A rated busbars.
I also always suspected/assumed that 150 thru 225 busbars were the same. Until now though, seems like no one would let the cat out of the bag. Once I had some siemens 150 and 250 amp panelboards. I measured the busbars and they were exactly the same. After measuring them, I couldn't remember which was which and was a bit concerned about which box to put them back in!
 
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