Breaker Panel Question

[goeduck]

Recently my circuit breaker to my septic tank discharge pump tripped. I am not sure why, but we had some weird power outages/flickers lately. I never had a reason to do anything with the circuit until the pump lost power and the tank went into high alarm. I always thought the breaker pair in the attached picture was for the jacuzzi pump and the "sump pump" label was just a generic label the original electrician used. There is a 12awg 3-conductor (plus ground) leaving the breaker panel. I ended up back tracing the circuit and found a j-box in the attic where they spliced the red conductor to the septic pump and the black conductor to the jacuzzi (sharing the neutral and ground). The white gizmo between the A and B breakers is a loose fit and the pump tripping out on circuit A did not trip off circuit B. I cannot imagine this is per code (house built in 1988), but my question now is should I remove the white gizmo to make two separate circuits? Also, is there a problem sharing the neutral and ground? Running a new dedicated circuit is not going to be easy. Appreciate the help.

 

[Roadworthy]

The first thing to determine is whether the sump pump or the jacuzzi is a 120 volt circuit. The only time a neutral is needed is for a 120 volt circuit and two 120 volt circuits should not share a neutral. For that matter if they are 120 volt circuits they should not be tied together at the breaker. I believe the jacuzzi should be on a GFCI breaker as well but I don't know what was code specific in 1988. You should probably consult a licensed electrician on this one. As an aside, sometimes a breaker will just get old and trip on its own without any overload. Sometimes when the handle is flipped the circuit won't open. ALWAYS make sure a circuit is dead even after tripping the breaker.

 

[ponytug]

This setup is normal. It is called a shared neutral, or a multi wire branch circuit(MWBC). Recent code requires that the A/B pair of the circuit have a dual pole breaker that is jumpered. This is supposed to prevent someone accidentally being shocked by working on one half of the circuit while the other is active, and who doesn't realize it is a MWBC.

Since in a 120/240 power set up, the two 120 legs are completely out of phase, any current in the neutral common to both circuits is canceled, so a multi wire branch circuit will never carry more than one circuit worth of current.

Don't pull the pin! Also don't go rearranging the breakers in your panel lest you accidentally put a MWBC on the same phase.

All the best,

Peter

 

[goeduck]

I had not heard of an MWBC circuit before, but a search for the acronym led me to the diagram below. Both the indoor jacuzzi and the septic tank pump are 120 VAC. The out of phase comment and neutral current cancelling makes a lot of sense. Some of the other breakers in the panel (Crouse Hinds) are hard connected and do not have the slop the white pin is allowing. Crouse Hinds is not currently making breaker panels as far as I know. I will pop open the panel and see what the hard connected breakers in there are (Siemens?). The septic pump circuit has an outdoor enclosure that would easily fit a GFCI if adding it to one side of the MWBC would not create some other problem. I have a low voltage background, some of the line stuff is new to me.

What is an MWBC?

MWBC is an acronym for multi-wire branch circuit. It is a method of wiring when an electrician uses one cable, for two circuits.

www.ahouseonarock.com

 

[Roadworthy]

A GFCI outlet could replace a regular outlet to feed your jacuzzi with no issues. Pay special attention to the "line" and "load" terminals to be sure it's installed correctly. The input power goes to the "line" terminals. I'm unsure which breakers would work in your panel but my old Westinghouse panel would take Siemens breakers as well al others. I think it even had a Cutler - Hammer breaker on my well pump. Take an old breaker to the store for comparison or do a little research to see what fits.

 

[goeduck]

Looks like Westinghouse is the other style in my panel which is also Eaton format and Home Depot has those. I think I will also get a full size single for the washer and slide down the 240V breaker a half slot and get rid of that spacer. I have two 200 amp panels (400 amp service), so no reason to get the slim ones. I don't even see a brand on them. Note how much slop the white pin allows between paired breakers.

 

[LouNY]

It needs the slop because it is not designed to trip both legs like a 220 breaker would.
But does allow and make it more obvious that they both should be turned off before servicing.