Mismatching MMCB Breaker and Enclosure Manufacturers

cottora

Member
Location
Atlanta, GA
I think I know the answer - the enclosure specifies "for use with". So I think using a breaker that is not listed as "for use" will not work.

Mods can delete if desired
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
The concern isn't matching manufacturers, per se, but approved breaker type in the panel's listing.

If a given Square D breaker model is acceptable per the GE panel labeling, it's allowed to be used.

BR breakers, for example, have been manufactured by more than one company over the years.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The enclosure is not the issue...the connection between the bus and the breaker is the issue.
You either use a breaker that is specified by the panel manufacturer for that panel bus, or you use a different brand breaker that that has been "classified" for use with that panel bus.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
When that connection is 2 or 3 bolts, if the spacing matches, is there plausibly a functional issue, or is it just a listing issue (it will work but it hasn't been tested)?

Cheers, Wayne
Most likely just a listing and/or approval issue....but those can be a real issue when there is some type of incident that ends up involving lawyers :D
 

dkidd

Senior Member
Location
here
Occupation
PE
The enclosure is not the issue...the connection between the bus and the breaker is the issue.
You either use a breaker that is specified by the panel manufacturer for that panel bus, or you use a different brand breaker that that has been "classified" for use with that panel bus.
OP didn't say that there was a panel(board) or bus involved, just an enclosure
 

jap

Senior Member
I can run that idea to ground. The 400A breaker is also the disconnect. Can a service disconnect be inside of a cabinet/box?
Doubt it.

I would think a service disconnect would have to have a way to be externally operable.

JAP>
 

jap

Senior Member
Code reference?

On another note there is 230.66 that requires service equipment be marked to identify as being suitable for you to service equipment. That may be a deal breaker for a DIY service disconnect enclosure.
Used to be this:


1637698534135.png

JAP>
 

jap

Senior Member
We've been shot down before because of the door on a MLO panelboard with a single large breaker in in attempts to reduce the cost of a larger 3r ECB fo this very reason of it not being externally operable.

Right or wrong it just stuck with me.

May not be the case by actual the rule of the NEC.

Never had a reason to question it.

JAP>
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Retired Electrical Engineer - Power Systems
We've been shot down before because of the door on a MLO panelboard with a single large breaker in in attempts to reduce the cost of a larger 3r ECB fo this very reason of it not being externally operable.

Right or wrong it just stuck with me.

May not be the case by actual the rule of the NEC.

Never had a reason to question it.

JAP>
Pull out style switches are typically not externally operable, nor are most meter mains.
Manufactures sell 'flat front' 3R enclosure for circuit breakers.
 
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