MWBC Handle ties

[Minuteman]

The 6 hour CEU 2008 code update course I'm taking was tonight for 3 hours and we have 3 more hours day after tomorrow. (Beats giving up 6 straight hours of a Saturday)

So, I was thinking about the handle ties. I have just use a 2-3 pole breaker that is common trip, never had a need for handle ties (back in the day, we slid in a piece of #10) but the instructor says that he prefers to use handle ties. I know that the ties are supposed to disconnect simultaneously, but do they always work that way? I mean, isn't it possible that 2 or 3 single pole breakers tied together could only have one open and the other(s) remain closed?

Has anyone experienced this, just one single pole in a handle tie opening? I just can't imagine the tie being that secure that it would effect the other breaker(s).

 

[iwire]

Handle ties are only interned and designed to ensure that when the breaker is turned off manually that all poles will open.

It is entirely possible that during a fault only one pole of a handle tied set of breakers opens.

 

[Minuteman]

Thanks Bob. Yeah, that was my thought. I think I will use the handle ties IF I install any MWBC under the '08, so that it might prevent a nuisance trip on the other circuit(s). :smile: