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Quad 2-pole circuit breaker

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qstorm

Electrical
Nov 17, 2002
16
PH
First time to see this 200A circuit breaker installation having quad 2-pole circuit breakers. This is a GE THQMV200L plug-in type breaker. Each line is served by two breakers.
GE-THQMV200La_uij7vb.jpg

I have to replace the CB due to loose line side contact fingers but it's not locally available. Can I work around this by using two 2-pole 100A CBs instead? What's the purpose of having two CBs in each line?
 
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Needed simply to get enough current thru the contact fingers.
No! You cannot use two two pole breakers because you could have one side trip that leaves the load powered but non-functional.

A jury-rig would be a non-removable bridge tying the two breakers together. Unclear on how to reliably do that.

I'd get the correct breaker or replace the panel with one rated for a larger single 2-pole breaker.

And watch out; that labeled handle alludes to each 1-pole breaker being rated 100A.

Keith Cress
kcress -
 
What's the reason for having parallel breakers, instead of having a single 2-pole 200A?
 
qstorm said:
What's the reason for having parallel breakers, instead of having a single 2-pole 200A?
Marketing...

Originally, the style of breaker you are looking at was only designed as a "100A frame", meaning the upper limit was 100A, then eventually got pushed to 125A. But if you wanted a Main Breaker for a residential load center (what these are limited to) that was for a 200A service, you needed to use a larger Molded Case Circuit Breaker (MCCB), which took up more space and, more importantly, cost more to make.

So as the demand went up for residential load centers in excess of 125A, load center manufacturers had to respond. In order to cut costs and win large residential projects, one of the manufacturers (I don't know who went first) got these "quads" listed as 200A, then shortly thereafter they all had to do it to stay competitive.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden
 
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