Thread: Both Hots From 3 Wire Cable on 120 Circuit Breaker

I saw a panel today where a 3-wire cable inside a panel had both hot conductors (the black and red) attached to the lugs of a Square D 120 volt breaker. Aside from this being wrong, what would the ramifications be of running an appliance off this 120 breaker when it is designed to be wired to a 240 breaker?

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Two loads using one neutral wire that carries combined current of the two loads.

Originally Posted by Vern Heiler

Two loads using one neutral wire that carries combined current of the two loads.

Originally Posted by Nick Ostrowski

I saw a panel today where a 3-wire cable inside a panel had both hot conductors (the black and red) attached to the lugs of a Square D 120 volt breaker. Aside from this being wrong, what would the ramifications be of running an appliance off this 120 breaker when it is designed to be wired to a 240 breaker?

Vern is correct, but to answer your question, only 120 volts are available to this circuit, so a 240 volt appliance would not run.

To get 240 volts, one of those wires could have been connected to an adjacent breaker.

The same thing could have been done to get two independent 120 volt circuits with less chance of overloading of the single neutral.

I believe if this was done, a tiebar is needed between the two adjacent breakers.

I assume that is a submarine panel and that you cut power before taking that picture?

If the appliance is rated for 240 volts it will not work as it is only receiving 120 volts. Breakers are only suitable for one conductor as well.

Originally Posted by Mark Kittle

If the appliance is rated for 240 volts it will not work as it is only receiving 120 volts. Breakers are only suitable for one conductor as well.

The op says "connected to a 240v breaker" not appliance, and I would assume that if the other end was connected to a 240v appliance it would have been corrected before now.

Originally Posted by John Kogel

I assume that ...you cut power before taking that picture?

That's the client's hand. Nick likes to get them involved in the inspection.

Originally Posted by Mark Kittle

Breakers are only suitable for one conductor as well.

Those Square D breakers are designed to accept two conductors.
Google it.

Nick, why this installation is wrong for 2 120 volt circuits was pointed out by Vern. Alternating current from the breaker sends out a pulse 60 times a second. The neutral completes the circuit and carries that same pulse. If you double the hots but don't double the neutral, it has to carry the current of both circuits. What if that load is two space heaters?
If the second hot, the red conductor, was on the other bus, the adjacent breaker, the pulse on that conductor is staggered so that it is increasing while the pulse on the black is decreasing. Current on the neutral will never be greater than the current thru one or the other of the hots.

Thanks guys. I suspected whatever runs off this circuit would probably not work properly or at all. The buyer told me he didn't want to put his hand in there but I told him if you want to own a house, ya gotta see what you can get away with before needing to pay to have the work done (that IS a joke).

This was actually for an inspection of repair items from the original home inspection I had done for the buyers about a month ago. It was obvious the seller did the repairs himself. On the original inspection, this subpanel was littered with improper double taps even on the Square D breakers. This circuit I posted about was previously OK during the original inspection but in the seller's attempt to make repairs, he ended up doing this.

What makes this even more interesting is I was the only person who was going to be there for the reinspection today. The buyers and their realtor were not attending. The realtor gave me the combo and I got to the house early following my morning inspection today. When I got home afterwards, I had a message on my machine from the buyer with a time stamp right about the time I started the reinspection. He said they decided to not have me do the reinspect so they could save money on my reinspect fee ($125.00) and that they would just have their realtor look at it. Oooooook.

I called the realtor, told him about the message the buyer left for me, and that I would not be issuing a report and I would not be passing any info along about what I saw during the reinspection.

The neutral can and will only have as the amperage of the breaker that the red and black conductors are attached to IE: 20 amp breaker would be max 20 amps on the neutral. now if they were on different phases in the panel IE: different breakers then the neutral would only carry the unbalanced load EX: one breaker with 15 amp load and one breaker with a 10 amp load the neutral would only carry 5 amps. Now if two breakers were on the same phase EX: one breaker with 15 amp load and one breaker with a 10 amp load the neutral would then carry 25 amps.

Originally Posted by Nick Ostrowski

what would the ramifications be of running an appliance off this 120 breaker when it is designed to be wired to a 240 breaker?

Why do you think it is from a 240 volt appliance?

Originally Posted by Vern Heiler

Two loads using one neutral wire that carries combined current of the two loads.

There may not be two loads on it. Both may also be connected to the same terminal at the other end, meaning that those conductors are in parallel (which is not allowed for that size wire), nonetheless, though, that 20 amp breaker is going to protect the neutral of the circuit at 20 amps (presuming that something else is not wired weird and the other end is connected to something weird and is sharing another conductor at that end.

What was that breaker labeled for on the circuit directory? (Probably not labeled. )

Originally Posted by Jerry Peck

Why do you think it is from a 240 volt appliance?



There may not be two loads on it. Both may also be connected to the same terminal at the other end, meaning that those conductors are in parallel (which is not allowed for that size wire), nonetheless, though, that 20 amp breaker is going to protect the neutral of the circuit at 20 amps (presuming that something else is not wired weird and the other end is connected to something weird and is sharing another conductor at that end.

What was that breaker labeled for on the circuit directory? (Probably not labeled. )

I don't know that the appliance at the end of the cable actually is a 240 volt appliance. I just wanted to know what the ramifications could be IF it was a 240 v appliance wired in this manner. And no, the panel was not labeled.

#12 3 wire cables are often used in residential work for kitchen counter circuits or for disposal/dishwasher circuits.

The first violation here is that you have parallel conductors with the black and red tied together - not permitted with wire this small.

The second violation could be one of several.

Placing the red and black on the same breaker makes them both the same circuit. If these go to the kitchen counter receptacles you have reduced the number of counter circuits, quite possibly to a lower quantity than code requires.

If the wires are to a appliance circuit it's possible the connected loads may be greater than permitted on one circuit.

Originally Posted by Nick Ostrowski

I just wanted to know what the ramifications could be IF it was a 240 v appliance wired in this manner.

What happens to the appliance depends on the type of appliance. If the appliance is heating only, such as a small toaster oven, then it will warm, at best, but not heat much, if anything. And if the toaster oven is like the one we have in our motor home with a manual spring wound timer, that's about all that will happen. However, if the toaster oven is digital or has an electronic control like the one we have at the house, then that control may or may not work (depending on how the appliance is wired internally).

If the 240 volt appliance was an oven, the elements would get warm (like the toaster oven above), and the electronic controls, well, that would depend on the internal wiring of the appliance and how those conductors are connected to the appliance (same goes for the toaster oven above).

Originally Posted by Bill Kriegh

If the wires are to a appliance circuit it's possible the connected loads may be greater than permitted on one circuit.

Could have been for a multiwire branch circuit and someone did not understand a MWBC and looked at its connection to two breakers and thought '240 volts, those appliances are not 240 volts', so they wired it up as 120 volts to each appliance. Most of the time is it likely that the breaker would not trip, but let's say that the dishwasher was in heated dry mode (or pre-heat/hot start) and someone flipped the disposer on, that breaker might trip.

After resetting the breaker they may have just assumed that something was wrong with the circuit sometimes as they did not understand what was going on (as we don't - because we don't have sufficient information ). They may have told others in the house 'Don't use both of those at the same time, the breaker might trip.' and it was left at that.

Originally Posted by Nick Ostrowski

Thanks guys. I suspected whatever runs off this circuit would probably not work properly or at all. The buyer told me he didn't want to put his hand in there but I told him if you want to own a house, ya gotta see what you can get away with before needing to pay to have the work done (that IS a joke).

This was actually for an inspection of repair items from the original home inspection I had done for the buyers about a month ago. It was obvious the seller did the repairs himself. On the original inspection, this subpanel was littered with improper double taps even on the Square D breakers. This circuit I posted about was previously OK during the original inspection but in the seller's attempt to make repairs, he ended up doing this.

What makes this even more interesting is I was the only person who was going to be there for the reinspection today. The buyers and their realtor were not attending. The realtor gave me the combo and I got to the house early following my morning inspection today. When I got home afterwards, I had a message on my machine from the buyer with a time stamp right about the time I started the reinspection. He said they decided to not have me do the reinspect so they could save money on my reinspect fee ($125.00) and that they would just have their realtor look at it. Oooooook.

I called the realtor, told him about the message the buyer left for me, and that I would not be issuing a report and I would not be passing any info along about what I saw during the reinspection.

Thanks for the rest of the story which all makes sense now.
Now that the realtor knows you've been back, maybe the clients should be told that there are new problems which could be harmful or even dangerous and leave it at that?.

Assuming those Square D circuit breakers are factory approved for terminating two conductors, there is nothing wrong with it. The neutral will not be subject to an overload because both wires are protected by the same circuit breaker. This is no different than one wire leaving the panel, going into a junction box with three NM cables and all spliced together with wire nuts. It makes no practical sense at all to do this, but there is no associated safety concern.

Originally Posted by Garry Blankenship

Assuming those Square D circuit breakers are factory approved for terminating two conductors, there is nothing wrong with it. The neutral will not be subject to an overload because both wires are protected by the same circuit breaker. This is no different than one wire leaving the panel, going into a junction box with three NM cables and all spliced together with wire nuts. It makes no practical sense at all to do this, but there is no associated safety concern.

Yes, the breaker will trip if the load exceeds 15 amps, assuming the breaker is good. So the neutral is protected somewhat.

But there is plenty wrong with this arrangement. Read Bill's post #13.

The neutral is forced to carry a greater load now because someone who had no business working in that panel has messed around in there. That panel now needs an electrician to figure out what's what and correct the unlabeled circuits.

Originally Posted by John Kogel

Thanks for the rest of the story which all makes sense now.
Now that the realtor knows you've been back, maybe the clients should be told that there are new problems which could be harmful or even dangerous and leave it at that?.

The buyers decided they wanted to save money and not have me inspect the repairs. That was the call they made and while I thought about that doing what you suggest, I'm not interested in letting somebody waste my time and still get something from me in the process for free. The realtor and I both said if the buyers want to roll the dice, that's their call.

WOW! Some of you guys are assuming WAY too much.

Who cares where these wires go? Is that how you write up your reports, on what something might possibly do???

Gary is right, and this IS a SqD that can accept two wires.

THIS IS NOT A VIOLATION, and is NOT a safety concern. The neutral WILL NOT, repeat, will NOT, carry more than the rating of that ONE circuit breaker. IF the two hots were on DIFFERENT breaker on the same panel phase then the current would be cumulative. Since there is only one breaker HOW in the world can it draw more current than the one breaker??

Also, HOW do you know these are a parallel conductors?? I'd bet any money that they are not. Either one is a spare or they do two different things.

No, it's not normal. No, I would not do this for any reason I can think of. But it is not a defect that I can see.
Maybe it is for two circuits and he could not fit a twin and some two-poles in there?

It amazes me how far (and sometimes incorrectly) some of you read into things.

Speedy, from the standpoint of an inspector's self-preservation (ie- avoiding complaints and lawsuits), yes, sometimes reports do have to be written with "what-if" scenarios in mind. All you need is one PO'd customer who thinks you did not warn them properly for your day to be ruined.

As for it not mattering where the wires go, what if the appliance attached to the end of those wires is designed to operate on a 240 volt circuit but now is on a 120 volt line. Isn't that an issue?

To Speedy and Garry and anyone else who thinks this is no problem, here's what we know.

Some of those breakers were triple-tapped, so Nick called for an electrician to repair. An amateur, not an electrician, made some changes, resulting in this mess we see now.

Amateur additions, followed by amateur attempts to correct, still no labels, still no inspection of the wiring which was added.

Maybe it's no big deal, but the evidence suggests that it could be. That many double taps indicate to me that circuits have been simply added on to existing circuits by a clueless amateur. If that was your house, would you check it out?