Reverse Feeding of Circuit Breaker

[choi1167]

Is this a common practice? Is there any article regarding this?

 

[itsmoked]

What size?!?!?

Smaller ones cannot tell any difference.

 

[dpc]

It is not common, but can be done. In the US, you would need a breaker that is UL listed for reverse feed.

 

[AusLee]

During a presentation, the Merlin Gerin guy said that for MCCBs it is not a problem, but he did not say for PACBs!

 

[dpc]

I'm pretty sure you can get LVPCB from GE rated for reverse feed. Don't know about other suppliers.

 

[wfowfo]

This is probably stating the obvious, but if it has a primary voltage closing coil (like the Cooper VXE's), you don't want to do it.

 

[choi1167]

It's an ABB 250Amp S4 MCCB. I guess I have to do a research on this breaker's technical specs.
My understanding is if the brochure or technical specs of a breaker specifically mentioned that it can be reversed feed then it's fine. But if not, then don't. I wonder if there's a more technical explanation on this.
On the other hand, the only other reason I see why the switchgear manufacturer reverse feed this breaker is to shorten the length of the bus bar connection to the main bus.

 

[BJC]

The NEC requires sinage on equipment that can be energized by more than one source. You may get a local inspector that will require a sign on the panel. Even if it's the only source of power an inspector may require the sign. an unsupecting electrican may think the panels is denergized from the "normal" source and find a branch cicuit that is hot.

 

[choi1167]

It's a good point BJC. Because somebody might think that even though the breaker is switched off the "load" side of the breaker is de-energized. But since it's reversed fed, that "load" side might still be energized. A sign should be installed for safety and compliance to NEC.

 

[choi1167]

BJC,

Do you know the exact section of NEC that mentioned this? Thank you.

 

[AusLee]

NEC 404.6. it even says what the sign should read.

 

[resqcapt19]

In the US, you would need a breaker that is UL listed for reverse feed.

The UL listing for molded case breakers says that they can be fed at either set of terminals unless the terminals are marked "Line" and "Load'.
Don

 

[tulum]

It has been my experience that any molded case breaker with a interchangable trip unit can be reverse fed. This has held true thus far on CH, SquareD, and ABB....

I do not know this for sure as a rule, it just has been my experience thus far.

 

[waross]

Does anyone know if OSHA has any requirements?

 

[tulum]

slight "typeO"...

My last post should read...


It has been my experience that any molded case breaker with a **non-interchangable** trip unit can be reverse fed.

OUCH! My Apologies...

Regards,
TULUM

 

[davidbeach]

Any circuit breaker with a UL listing (so doesn't necessarily apply to the IEC realm) is reversible UNLESS terminals are labeled "Line" or "Load".