Questions tagged [mwbc]

Use this tag for questions about Multi-Wire Branch Circuits, sometimes called "Edison circuits".

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63 views

Overloaded circuit on ungrounded outlets

So I've stumped/annoyed most of the internet with this one. I hope there might be someone who can point me in a different direction.. I have a house built in 55 with ungrounded outlets. A space ...
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2answers
137 views

Connecting 120/240 receptacles on the same circuit breaker

I want to add a branch circuit to the control panel using 12/3 wire and protected by 20 amp double pole circuit breaker. Is it safe to connect multiple duplex receptacles 120 volts and 240 volts on ...
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2answers
69 views

MWBC for Fridge and Microwave

I've recently learned about Multi-Wire Branch Circuits and intend to use one to provide dedicated circuits for both my built-in microwave and refrigerator. I understand the requirements around handle ...
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2answers
188 views

Possible to ground-fault protect both legs of a MWBC with two single-pole breakers?

To get a MWBC working, with both legs GF protected, I installed 2 Single Pole GFI breakers, on adjacent slots, with a handle-tie. Since there are 2 lugs for Neutral wires, and only one neutral coming ...
4
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2answers
446 views

is this the right way to ground fault protect both sides of an mwbc?

is this the correct way to ground fault-protect both sides of an mwbc? pigtail the (line) neutral to two separate gfci outlets, and pigtail the (load) neutrals to the neutral that's going outside.
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1answer
67 views

Microwave on 220 volt branch

A friend has a microwave on the same circuit as electric stove. Independently they work fine but if an element on the stove is on and the microwave is turned on the breaker goes off. An electrician ...
2
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2answers
695 views

Understanding the wiring of 2-Pole Quad Circuit Breakers

I only want to understand the concept, so you dont have to address if my panel accepts tandem breakers or a certain brand of breakers. I will also omit any reference to ground wires for clarity. I ...
4
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1answer
579 views

Why are tandem breakers on shared neutral (MWBC) problematic?

I hear that shared-neutral or multi-wire branch circuits (MWBC) can have issues when used with tandem breakers (also called duplex, twin, cheater or double-stuff breakers). What is the issue there? ...
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3answers
85 views

2 breakers - should they work as one?

I have a circuit with 2 15 amp breakers. They don’t act, individually they both have to be shut off to shut off the circuits. Am I looking for an outlet with two devices? Example switch and outlet? ...
1
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1answer
154 views

Can I use a two-pole single handle breaker for mwbc?

I have a mwbc with two 20A breakers with their handles clipped for common trip. Can I replace this ensemble with a single two-pole 20A breaker with just one handle? New panel in CA. I'm unsure ...
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2answers
616 views

Best way to get both 120V and 220V from existing multiwire branch circuit (MWBC)

I have a double pole 20A breaker feeding a 120V MWBC with 12/3 with ground, romex that goes up three levels to two separate 120V duplex GFCI receptacles with common neutral. I want to have both 120V ...
4
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2answers
407 views

MWBC (Multi-Wire-Branched-Circuit) w/out joined breakers, how best to fix?

I was trying to replace a fan/light in my living room with a new led light, and have found that the living room branch circuit (lights and outlets) is actually fed by a Multi Wire Branch Circuit (14-3)...
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2answers
2k views

Change from 240V to 120V

I did quite a bit of research including on this forum but wanted to double check if I got things right. On the outside of our home there is a standard electrical box (guessing about 3"x5") to install ...
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1answer
49 views

MBWC using two twin breakers with middle handles tied

My question is whether overload protection will work for the two handle tied circuits described below: Four separate circuits are involved. These are in a residence, feeding outlets and lights, ...
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2answers
100 views

Separate Phases for Residential Wiring

I am trying to find out if I can use a 14/3 cable to power two separate circuits, and to do that I know I must use two separate phases, but I am not sure how to do that.
2
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1answer
396 views

120/240 Multi wire branch circuit - failed inspection because of uneven loads?

From a double pole 20-amp breaker, I ran 12/3 w/g to a quad box with a 120 receptacle and a 240 receptacle. Red wire from one pole of the breaker to the 240, ground to the grounds, white to neutral ...
3
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2answers
587 views

Could the black and white wires in a three-wire cable both be used as hots?

In my detached garage, there is a ??/3 cable (haven't measured to know the gauge, though I'm thinking it's 10..) coming into a fuse box with two circuits. The strange thing is, the third conductor is ...
5
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2answers
207 views

Can I use a ground rod as an equipment ground for a detached garage?

I'm in a bit of a dilemma. The house we bought has a detached garage supplied by 12/3 UF with ground. The previous owner/handyman set this up as a multiwire branch circuit (MWBC) with a twist: one ...
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2answers
126 views

Requesting Evaluation of Power Plan at Rural Cabin

What I am looking for is guidance and honest evaluation. I'm not afraid of being wrong. I want to save some bucks and learn some things, without blowing myself up. So please tell me if I'm doing ...
2
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1answer
2k views

Multi-Wire Branched Circuit and GFCI

Forgive me if this a repeat, but I'd like to be sure I know exactly what's going on. I am installing 2 bathroom fan/light fixtures directly over the tub in 2 adjacent bathrooms on the same circuit. ...
21
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2answers
6k views

What is a tandem breaker (aka duplex, cheater, twin, double-stuff, etc.)?

I keep hearing about tandem breakers, and how they won't work with 240V loads and how they should never be used for a multi-wire branch circuit. Aside from those issues... What is a tandem breaker? ...
3
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2answers
68 views

Using a 1-pole GFCI to test half a multi-wire branch circuit

I'm searching my electrical system for defects, fixing the last guy's work. He loved to cross neutrals (grab a hot from circuit 5 and neutral from circuit 19). I've found several instances, but it's ...