Is there a 250A breaker which fits this panel?

Irving LaRue

Irving LaRue

Member
Location
Warrenton, Virginia
Occupation
Electrician Apprentice
I’m running a set of 500kcmil wires for a panel which will feed some car chargers in a parking garage.

There’s a disagreement between my project manager and the resident electrician for the garage. My PM doesn’t believe this panel can fit a 250A breaker. He thinks they don’t make them for this size panel. Which means I’ll need to pipe into a disconnect and tap into the lugs.

The electrician here thinks they do. Which would save us time and money.

What is your opinion? Thanks!
 

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Will the panel take any breakers besides EDB? It looks like the EDB series tops out at 125A when looking at the SquareD catalog.
 
There may be a position in the bottom of the panel to mount feed thru lugs or a Frame breaker.
I think you loose a few breaker positions if you do that.
Are you going to a 240V transformer for level 2 chargers or is this a level 3 charger?
 
pipe_bender said:
There may be a position in the bottom of the panel to mount feed thru lugs or a Frame breaker.
I think you loose a few breaker positions if you do that.
Are you going to a 240V transformer for level 2 chargers or is this a level 3 charger?
Click to expand...
I don’t think losing spaces is of any concern for this application. The panel only has 3 breakers inside.

Can you explain the concept of a frame breaker?

I think it’s a level 3 charger, but I’ll need to confirm.
 
Field install not possible, unless it came from the factory with special provisions for that large of a branch breaker. The space would be noticible due to the knockout for the handle at the top or bottom.
 
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Breaker "frames" refer to the fact that circuit breakers are made in only a certain number of "frame sizes", within which you can have multiple different trip ratings that are at or under that frame size. So for example a 125A frame breaker is going to cover anything from 10A to 125A trips, but the physical sizes will all be the same. The frame sizes vary from manufacturer to manufacturer, but GENERALLY go 125A, 250A, 400A, 800A, 1200A etc.. The trip sizes may also overlap a little, so for example you might be able to get a 200A trip in not only a 250A frame, but also a 400A frame. When you see this on drawings, you will see something like "250AF/200AT" which means 250A Frame with a 200A Trip. The 3 breakers in your panel then are 125AF/125AT.

I tried (a little) to decode that part number (on the blue sticker). Oddly, the first "12" after the NF would indicate it is a 125A panel, but the label shows it as a 400A rating. So it was likely something custom assembled to order, as in a 400A panel bus with main lugs only, but that only has provisions for 125A frame branch breakers. Panel assemblies have to be made with "provisions" to accommodate the branch breakers, based on the maximum possible size you want, due to the required wire bending spaces. So if you want a 400A panel to accommodate a 250AF branch breaker, the box width has to be able to provide enough wire bending space for up to 250A conductors, even if nobody ever actually uses one. So in this case, someone likely wanted the narrowest box they could get, which made it limited to the smallest frame size of breakers, 125AF.

Side note: the first pic is just the part number for the cover...
 
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