I see no need for two devices immediately in series as needing to be considered separate items unless there is a very high probability of a short circuit occurring between them. In your case the fuse will clear before the upstream device so the performance of the shunt trip breaker is immaterial.Hi All, I'm reviewing a project where they have two elevators fed from a single feeder and main breaker. Each elevator has a disconnect panel containing a shunt breaker and a fuse block in series. The shunt breakers do not coordinate with the main breaker, but the fuses do. Is this OK? Or do the shunt breakers need to coordinate as well? TIA
Good point, I'll check. This is in California. Do you happen to know a CA code reference for that?Check with local requirements on whether the shunt trip can be located in the elevator room. Not all municipalities allow this. California, specifically, does not.
No I can't tell that it does.Is the shunt trip device required to have over current protection at all?
That's what I thought, thanks for confirming.
Good point, I'll check. This is in California. Do you happen to know a CA code reference for that?
No I can't tell that it does.
Thanks again.
I have never heard of this work around. Would you be able to provide a source? In my interpretation of the code, it seems that all devices that protect the elevators would need to coordinate with the upstream breakers.This is a work around for when downstream breakers don't coordinate. Consider the shunt trip breaker to be a safety disconnect and the fuses ultimately protect the upstream breaker from taking down both cars. Check with local requirements on whether the shunt trip can be located in the elevator room. Not all municipalities allow this. California, specifically, does not.