Panel busbar rating

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Electriman

Senior Member
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Greetings,

I have a residential panel that does not have any label. The main breaker is 200A but I don't know if the busbar is rated for 225A so I can use it for solar. is there anyway that I can find out if the busbar is rated for 225A? I have the busbar measurements and if there is a cheatsheet to use for busbar ratings that would be great. Any recommendation?

Thank you in advance.
 
Electriman said:
Greetings,

I have a residential panel that does not have any label. The main breaker is 200A but I don't know if the busbar is rated for 225A so I can use it for solar. is there anyway that I can find out if the busbar is rated for 225A? I have the busbar measurements and if there is a cheatsheet to use for busbar ratings that would be great. Any recommendation?

Thank you in advance.
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If it is a 200A Eaton Cutler Hammer, it has a 225A busbar. The newer ones have a sticker that says that on the inside of the enclosure.
 
ggunn said:
If it is a 200A Eaton Cutler Hammer, it has a 225A busbar. The newer ones have a sticker that says that on the inside of the enclosure.
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Like I said there is no label to find out the the manufacturer and it is an older panel.
 
Electriman said:
Like I said there is no label to find out the the manufacturer and it is an older panel.
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If you cannot determine the capacity of the bus you must assume it to be equal to the rating of the MCB. Been there, done that, didn't like it much.
 
electrofelon said:
I agree for load center type panelboards, but for true panelboards there is often more hope. For example, a Siemens P1 panelboard will have either a 250 or 400 A bus.
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I'm pretty sure he is speaking of a residential load center.
 
Panel board bus bars are usually rated based on temperature rise and not by their physical dimensions.
 
What I can conclude from the above statements is that we can't verify if the bus is actually 225A based on the dimensions due to other limitation factors involved. So we would be to upgrade it.
 
Electriman said:
What I can conclude from the above statements is that we can't verify if the bus is actually 225A based on the dimensions due to other limitation factors involved. So we would be to upgrade it.
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I still think you could make a strong case to AHJ for accepting the 200A rating , with the main and if your wire size aligns. Then switching out the main.
 
electrofelon said:
Yes, I mentioned this for completeness, for those who may be reading and not well versed in some of the differences between load center type panel boards and true panel boards.
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Neither UL nor the NEC make differentiation between panelboards and loadcenters. For the most part loadcenters are designed the be low cost and fit into wall cavities with 16" stud spacing, there is nothing to prevent them from being in commercial and industrial installations, except project specifications.
 
jim dungar said:
Neither UL nor the NEC make differentiation between panelboards and loadcenters. For the most part loadcenters are designed the be low cost and fit into wall cavities with 16" stud spacing, there is nothing to prevent them from being in commercial and industrial installations, except project specifications.
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Yes I am aware if that Jim, I was pointing out some of the practical differences, such as likely more readily documented bus bar ratings, minimum bus bar ratings, and likely wider disparity between main breaker rating and the bus bar rating.
 
electrofelon said:
Yes I am aware if that Jim, I was pointing out some of the practical differences, such as likely more readily documented bus bar ratings, minimum bus bar ratings, and likely wider disparity between main breaker rating and the bus bar rating.
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I think those items are more dependent on the manufacturer than if it is a loadcenter versus a panelboard.

You don't get what you don't pay for.
 
The
jim dungar said:
I think those items are more dependent on the manufacturer than if it is a loadcenter versus a panelboard.

You don't get what you don't pay for.
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The point was, with a panelboard you get well documented bus bar ratings, unlike load centers where it seems to be top secret. As I said, with Siemens you get a minimum of 250A bussing even if it's a 200A MB. I can't speak for other manufacturers off the top of my head.
 
electrofelon said:
The
The point was, with a panelboard you get well documented bus bar ratings, unlike load centers where it seems to be top secret.
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Many load centers have a sticker on the inside wall of the enclosure that shows the busbar rating. That said, if the sticker shows a 225A busbar in a 200A panel, that does not mean you can replace the 200A main breaker with a 225A one.
 
ggunn said:
Many load centers have a sticker on the inside wall of the enclosure that shows the busbar rating. That said, if the sticker shows a 225A busbar in a 200A panel, that does not mean you can replace the 200A main breaker with a 225A one.
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Sure sometimes they do, sometimes they don't. There also seems to frequently be a quirky labeling thing with load centers (never seen this with panelboards) where a factory installed main LOWERS the bus bar rating - that is they won't provide a separate bus rating or will say it matches the main breaker installed.
 
ggunn said:
Many load centers have a sticker on the inside wall of the enclosure that shows the busbar rating. That said, if the sticker shows a 225A busbar in a 200A panel, that does not mean you can replace the 200A main breaker with a 225A one.
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Can you elaborate on this? Why wouldn't you be able to upgrade the main breaker?

Rob G, Seattle
 
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