Double fed

[boogieman]

Hello all. I have a technical question regarding an installation. In a single-family dwelling I found the following: a branch circuit connected to two different breakers in the interior sub-panel. Both breakers are on the same phase and are both 15 amp. There is a #14 connected to each of the two which then connect to a third #14 under a wire nut. This third conductor is the load wire to the branch circuit itself.


..............................a or b phase.....................................
/ \
/ \
/ \
cb1---------------------------------0-----------------------------------------------------cb2
15a \ 15a
\
\...............................to branch circuit

The person that did this is trying to convince me that this would allow 30 amps of overcurrent protection, but I believe it's still 15. Either way I'm going to disconnect the circuit from one of the breakers, as the installation is dangerous in my opinion, especially for anyone working on it. I was just wondering how the breakers would operate, or fail to correctly, in relation to the branch circuit. Thanks for your help, gm

 

[infinity]

Yes, since the two 15 amp CB's are in parallel it would require at least 30 amps to trip either OCPD. This is both unsafe and in violation of the NEC.

Welcome to the forum.

 

[boogieman]

Hi. thanks for the reply. My schematic didn't come out like i planned, but I think you got the idea. I'm definitely going to fix the installation. I usually see this type of mistake in new houses, except with the double feed occurring in a multi-gang switchbox as opposed to the panel where it is more obvious. Thanks again and have a great holiday!