Two breakers with handle-tie or two pole breaker?

[sw_ross]

This is just for confirmation of what I think I know. Please enlighten me if I'm wrong in my understanding of this topic.

With a multi-wire branch circuit you have to use two separate breakers with a listed handle tie, 210.4(B), 240.15(B)1.

My 2 questions are:

1) Is it allowed to use a 2-pole breaker for a multi-wire Branch circuit (or 3-pole for a 3 phase mwbc)?

2) Outside of this mwbc topic, any branch circuit that has line-to-line loads you have to use a 2-pole breaker with a common trip (two separate breakers with handle tie doesn't qualify)?

I just want some clarification on this issue to make sure I'm not being unjustly critical on fellow workers.

Thanks,
Sky

 

[LarryFine]

1. Absolutely.

2. Correct, also.

The common trip is for simultaneous automatic operation, and is separate from the handle, which is for manual simultaneous operation.

 

[sw_ross]

Thanks for the reply.

I've seen unlisted handle-ties where there was enough slop that if one breaker tripped, the other could stay engaged. Are listed handle-ties "listed" because they are tight enough to trip both breakers if one trips?

Thanks again,
Sky

 

[raider1]

Thanks for the reply.

I've seen unlisted handle-ties where there was enough slop that if one breaker tripped, the other could stay engaged. Are listed handle-ties "listed" because they are tight enough to trip both breakers if one trips?

Thanks again,
Sky

No, handle ties are not design as a common trip element and must never be relied upon to function as such.

A handle tie may or may not trip the other breaker when there is a fault.

Breakers are designed to be "Trip free" which means that the trip mechanism is designed to trip independent of the handle. This provides for the allowance to lock a breaker in the on position and the breaker will still function properly.

Also 240.15(B)(2) and (B)(3) permit single pole circuit breakers with identified handle ties to be used top protect line to line loads.

Chris

 

[sw_ross]

Thanks, that helps clear things up a little in my mind. You're not relying on the listed handle-tie to open up the other breaker if one trips, only to 'simultaneously disconnect' all ungrounded conductors, 210.4(B).

Thanks for straightening out my thinking, sometimes I get a little conviluted.
Sky