Line and Load side of breakers?

Status
Not open for further replies.
A

adelle

Member
I know from a strict electrical perspective there is no difference between the line and load side of a basic circuit breaker. But what does UL or the NEC say?

Reason I ask is I was delivered a custom order 600a 480v Square D MLO panel where the two factory installed breakers (300a and 250a) are wired backwards. That is the line comes in on the bottom and the load comes out the top side - on both breakers. The panel bears a UL sticker but I still wonder if this is up to code?
 
could you clarify that you mentioned you have a MLO panel and then proceed to describe what sounds like a main breaker. Or are you describing a two section panel with a main for each section and main lugs ahead of this?

Sounds like you have a panel that is intended to be bottom fed. If it were to be top fed they would use the same breaker on the other end of the busses and it is designed to be fed on either end. Although not all of them are.
 
Both UL and the NEC do not have any requirements for in and out unless the breaker is specifically marked to indicate Line and Load.

So, unless the breaker is marked otherwise, there is no issue.
 
Status
Not open for further replies.
Top