Backfeeding a Circuit Breaker

[FaradayFF]

Greetings,
Does a typical thermal magnetic circuit breaker retain its tripping characteristics regardless of the direction of the current flow through it? If one connected a temp. generator to a panelboard branch circuit breaker forcing the current in the opposite direction to expected(conventional) load flow direction, would the breaker trip if its amperage rating was exceeded?
I think so, these tripping elements in the molded case units are not direction sensitive, are they?

Thanks,
EE

 

[tom baker]

Some breakers are labeled line and load, others are not. That would allow some to be backfed, but I can not comment how trip elements are direction sensitive.

 

[LarryFine]

It seems the breaker wouldn't "know" or "care" which way the current is flowing. The only difference I can see is that the contacts are normally on the load side of the elements.

 

[jaggedben]

Greetings,
Does a typical thermal magnetic circuit breaker retain its tripping characteristics regardless of the direction of the current flow through it? If one connected a temp. generator to a panelboard branch circuit breaker forcing the current in the opposite direction to expected(conventional) load flow direction, would the breaker trip if its amperage rating was exceeded?
I think so, these tripping elements in the molded case units are not direction sensitive, are they?

Thanks,
EE

I'm nearly 100% certain that a 'typical' thermal magnetic circuit breaker operates the same in either direction, if by 'typical' we mean no special electronics features such as GFCI, AFCI, or GFP. I have never seen a 'typical' thermal magnetic breaker marked Line and Load from the factory. FWIW, I backfeed breakers for a living.

 

[LarryFine]

FWIW, I backfeed breakers for a living.

The Backfeeder. Sounds like a villain in the next Incredibles movie.

 

[junkhound]

ac breaker either direction as far as tripping concerned,, if breaker has other functions such as remote reporting, varies with type.

dc breaker most only one way

 

[oldsparky52]

The Backfeeder. Sounds like a villain in the next Incredibles movie.

As soon as I read jaggedben's post, I thought of ...