Thread: All circuits 12/3 in panel

How would you comment on the fact that almost all of the circuits in the distribution panel are utilizing 12/3 on the 110 volt circuits? I'm finishing the report right now and would love to hear from you guys about this. Thanks! David

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From the picture I can't really see what's going on. If it's all 12/3 I assume that means a bunch of shared neutrals. I personally think evaluating the circuit design is way beyond what's expected of us as HIs. If I commented at all it would be very general.

That would indicate the house was wired with multi-wire circuits.

Nothing against code in that, personally, though, I dislike multi-wire circuits and prefer to wire in paired neutral/hot (12/2).

To me, multi-wire circuits indicates 'done on the cheap' so as to save (in the case shown) those 8 single runs of #12 ... gimme a break, that is not much money to try to save.

Dave, from that pic it looks like there was 2 220v circuits;and the rest were 120v in which I coud not read the ratings as longas those breakers do not exceed 20 amps I see no problem..

Dave on further reveiw the breaker on the right side of the panel six down appears to be double luged ,could not tell iif that was a double throw breaker if not thats a concern

Thanks for all the replies! I won't comment on it in the report then. Man you guys are fast...appreciate the help. Dave

I call out shared neutrals on a neutral bus bar due to the possibility of a backfeed situation. With the setup on this panel where each of the 12/3 wired circuits share a neutral, shouldn't their be a tie between the breakers to ensure that you turn off both circuits sharing the same neutral?

Originally Posted by Dave Mortensen

I call out shared neutrals on a neutral bus bar due to the possibility of a backfeed situation. With the setup on this panel where each of the 12/3 wired circuits share a neutral, shouldn't their be a tie between the breakers to ensure that you turn off both circuits sharing the same neutral?

Dave,

No. Only if both circuits are connected to the same device, such as one to each half of a duplex receptacle outlet or switch. It would be a good idea, though.

On an additional note, I try to trace the multi-wire circuits to ensure that they do indeed read 240 v across the two "hot" conductors. If not, it is possible to overload the neutral. In that panel it should be fairly easy to trace the conductors. Many of the panels in my area are too tight to effectively do this.

By the way, the grounds are bundled. But you probably already knew that.

Thanks Gunnar,
I know that a duplex outlet for the garbage disposal and the dishwasher share the neutral...is there any other outlet situation where this may occur? Maybe a switched living room outlet? Is it even worth mentioning that there COULD be a problem?
You'd be surprised how many electricians bundled the grounds up here (or maybe you wouldn't!). I call it, but it's rarely separated. Thanks again, David

The attitude seems to be "I never saw it before, it's different, therefor it must be somehow wrong." Don't blame the world for your lack of experience!

Whether or not to 'share' neutrals is a design issue, up to the discretion of the installing electrician. Regardless of voltage ... as long as all the 'hots' are fed by different legs, and the legs are of approximately the same voltage to ground, the use of shared neutrals is perfectly proper.

Can things go wrong, especially in the hands of unqualified personnel? Absolutely. That's part of the reason I prefer to avoid using them in homes. Yet, my preference is far different from being a code requirement.
Likewise, it's nice that all the hots terminate in breakers mounted next to each other - but, again, that hasn't been code.
Handle ties? Generally, IMO, a poor idea. It's really nice that ONLY the faulted circuit trip; this helps identify which circuit has a problem, and you're not shutting off the lights when a appliance served by the other leg faults. This is but one area where the 2008 NEC is causing some unhappiness.

Yes, the 2008 NEC greatly changes the way the code looks at multi-wire branch circuits. I consider that discussion to be beyond the scope of this thread.

So, why would an electrician chose to use this method? Primarily, to make room for more circuits in the conduit, and to reduce the clutter in the panel.
Limiting ourselves to Romex as the wiring method under discussion (since that is the primary residential method), running two separate 12/2's brings 6 wires into the panel - two hots, 2 neutrals, two grounds. Use 12/3, and there are now only 4 wires .... 2 hots, 1 neutral, 1 ground. This also means an easier pull (round wire vs. flat), fewer staples, less attic clutter, etc. There can be some cost savings as less wire may be used as well.

Originally Posted by John Steinke

Whether or not to 'share' neutrals is a design issue, up to the discretion of the installing electrician.

There can be some cost savings as less wire may be used as well.

That's what I said.

I would certainly be interested in finding out if this was the electrical contractor following the design of the home spec's or simply cutting corners.

Yes. There is a big difference in the amount of work, headache and some cost savings associated with the 12/3 use. My money is on the electrical contractor having made the change as this is not common.

Rich

Originally Posted by Dave Mortensen

Thanks Gunnar,
I know that a duplex outlet for the garbage disposal and the dishwasher share the neutral...is there any other outlet situation where this may occur? Maybe a switched living room outlet? Is it even worth mentioning that there COULD be a problem?
You'd be surprised how many electricians bundled the grounds up here (or maybe you wouldn't!). I call it, but it's rarely separated. Thanks again, David

David,

Without doing a complete evaluation on all of the circuits, there is no way to determine if anything other than the dishwasher/disposal shares a receptacle outlet. So, either you have to disclaim multi-wire circuits in your report every time you run into them, or you just have to accept that tracing individual circuits goes beyond SOP of a standard home inspection. Tracing the multi-wire circuits would be for someone doing an "in-depth" inspection and that would necessarily cost more.

Originally Posted by John Steinke

The attitude seems to be "I never saw it before, it's different, therefor it must be somehow wrong." Don't blame the world for your lack of experience!

Whether or not to 'share' neutrals is a design issue, up to the discretion of the installing electrician. Regardless of voltage ... as long as all the 'hots' are fed by different legs, and the legs are of approximately the same voltage to ground, the use of shared neutrals is perfectly proper.

Can things go wrong, especially in the hands of unqualified personnel? Absolutely. That's part of the reason I prefer to avoid using them in homes. Yet, my preference is far different from being a code requirement.
Likewise, it's nice that all the hots terminate in breakers mounted next to each other - but, again, that hasn't been code.
Handle ties? Generally, IMO, a poor idea. It's really nice that ONLY the faulted circuit trip; this helps identify which circuit has a problem, and you're not shutting off the lights when a appliance served by the other leg faults. This is but one area where the 2008 NEC is causing some unhappiness.

Yes, the 2008 NEC greatly changes the way the code looks at multi-wire branch circuits. I consider that discussion to be beyond the scope of this thread.

So, why would an electrician chose to use this method? Primarily, to make room for more circuits in the conduit, and to reduce the clutter in the panel.
Limiting ourselves to Romex as the wiring method under discussion (since that is the primary residential method), running two separate 12/2's brings 6 wires into the panel - two hots, 2 neutrals, two grounds. Use 12/3, and there are now only 4 wires .... 2 hots, 1 neutral, 1 ground. This also means an easier pull (round wire vs. flat), fewer staples, less attic clutter, etc. There can be some cost savings as less wire may be used as well.

Well Said John

I definitely am not the one to trace circuits throughout the home on a 2-3 hour home inspection, but my question was should I warn the client of potential problems with the multi-wired circuits? I'm getting the feeling that not many of you have run into this before, however the concensus seems to be that it's not noteworthy.

Byron Lentz stated, "The attitude seems to be "I never saw it before, it's different, therefor it must be somehow wrong." Don't blame the world for your lack of experience!"

I really can't see anyone saying that in the replies and I asked the question because of the unusual installation (and yes, it is due to my lack of experience). I think a lot of people use this board for education purposes, especially when running into unusual electrical situations. Thanks to all who responded in a professional manner and were willing to educate me on the subject.

3 conductor circuits are allowed provided the breakers are on appropriate panel legs and the handles are tied together.

What would your reporting language look like if you came across the above panel and there were no handle ties?

Personally, I have run across romex being wired as two separate cicuits with the two breakers not tied together. I call them as a safety hazard, since quite often an unsuspecting individual will turn off a breaker to work on a switch, outlet, or whatever, not knowing the wire is still hot, and may inadvertantly cut the wire. To me it's a case of common sense as opposed to relying on a code requirement, which may not be valid or adequate.

Originally Posted by Bob Knauff

3 conductor circuits are allowed provided the breakers are on appropriate panel legs and the handles are tied together.

Bob,

The breaker handles do not need to be tied together unless both legs of the multi-wire circuit go to the same device strap.

I wish that were a requirements, but it is not.

It's also easy for a do-it-yourself homeowner (and we all know they work on their own homes) to 're-arrange the circuits' while adding or removing something, and that is not a good thing with multi-wire circuits as you could end up with both legs on the same phase bus, which would cause the neutral to carry *BOTH* loads (assuming loads are 'on' on both legs, potentially resulting in twice the neutral current as the circuit was designed for) instead of either *ONE* load (assuming only one load is 'on' one leg) or *THE DIFFERENCE* between both loads (assuming loads on 'on' on both legs, only the difference in their current is carried by the neutral).

Again, allowed, yes.

Usually done to save money.

Is it a reportable item?

It would not hurt to advise your client that the panel has one or more (in this case all or almost all) circuits which are multi-wire and that extreme care should be used when they are anyone else is attempting to do any work in the panel, extreme care meaning that the multi-wire circuits should not be relocated without knowing what a multi-wire circuit is and what is required of a multi-wire circuit (i.e., that a multi-wire circuit is two 120 volt circuits, wired as a single 240 volt circuit with a neutral, and with *NO* 240 volt loads allowed on that circuit).

Jerry, thanks for adding your last paragraph, thats exactly the point I was trying to make.

When I was doing some work years ago on a house and kept wondering 'How come I keep getting bit (arcs) on these neutrals? WTF is going on???

Then the light came on: Multi-wire circuits! *I* had turned off the breaker to the circuit *I* was working on (which was rare for me, I usually worked on things 'hot'), however, the other leg of that multi-wire circuit (another breaker not tied to the first one) was still 'hot', which meant full current from the load on THAT leg was on the shared neutral!

Crimeny, I had to be careful of what I did in that panel.

Originally Posted by Dave Mortensen

I definitely am not the one to trace circuits throughout the home on a 2-3 hour home inspection, but my question was should I warn the client of potential problems with the multi-wired circuits? I'm getting the feeling that not many of you have run into this before, however the concensus ted, "The attitude seems to be "I never saw it before, it's different, therefor it must be somehow wrong."

I really can't see anyone saying that in the replies and I asked the question because of the unusual installation (and yes, it is due to my lack of experience). I think a lot of people use this board for education purposes, especially when running into unusual electrical situations. Thanks to all who responded in a professional manner and were willing to educate me on the subject.

Dave,

I see multi-wire circuits regularly, particularly in newer construction. As I tried to indicate, I will look for the dishwasher/disposal circuits without handle ties and I will try to identify multi-wire circuits that are on the same leg (tester reads 0 instead of 240 volts across the two legs) because this will overload the single neutral. I find improperly wired circuits once or twice a month. If the panel is a combination meter/main/distribution panel, the panel is often too narrow and there are often too many wires to try and trace to where the cable sheathing begins and I will not be able to identify proper or improper multi-wire circuits.

Originally Posted by Jerry Peck

It would not hurt to advise your client that the panel has one or more (in this case all or almost all) circuits which are multi-wire and that extreme care should be used when they are anyone else is attempting to do any work in the panel, extreme care meaning that the multi-wire circuits should not be relocated without knowing what a multi-wire circuit is and what is required of a multi-wire circuit (i.e., that a multi-wire circuit is two 120 volt circuits, wired as a single 240 volt circuit with a neutral, and with *NO* 240 volt loads allowed on that circuit).

Get ready for your phone to ring off hook. 'Is this a problem?' 'What should I do?' 'The seller had the house inspected 3 years ago and this didn't come up' 'The electrician doesn't know what you want'

The advice is sound and true..... it's just that sometimes it's best to let sleeping dogs lie.... at least IMO.

You'll never get in trouble for not mentioning it. You risk totally confusing people for no benefit. The assumption that we must work under is the people who touch the house in the future are qualifed to do so. Otherwise, it's an endless slippery slope.

Originally Posted by Matt Fellman

Get ready for your phone to ring off hook. 'Is this a problem?' 'What should I do?' 'The seller had the house inspected 3 years ago and this didn't come up' 'The electrician doesn't know what you want'

The advice is sound and true..... it's just that sometimes it's best to let sleeping dogs lie.... at least IMO.

You'll never get in trouble for not mentioning it. You risk totally confusing people for no benefit. The assumption that we must work under is the people who touch the house in the future are qualifed to do so. Otherwise, it's an endless slippery slope.

I tend to agree with Matt. Maybe a general note in the electrical section of the report that states that any work on the electrical system should be performed by a licensed electrical contractor. This could be done without alarm, but still gives warning. There are many other reasons that an untrained or partially untrained homeowner should not work on electrical systems, whether or not they have multi-wire circuits.

All simple answers.

Originally Posted by Matt Fellman

Get ready for your phone to ring off hook. 'Is this a problem?'

No. It was a warning to you not to started moving breakers around in your panel.

'What should I do?'

Don't move breakers around in your panel, call an electrical contractor is you need to have any work done in there.

'The seller had the house inspected 3 years ago and this didn't come up'

That may have been because the other inspector was not fully aware of multi-wire circuits and how easy it is to screw them up, or, may they did not want to 'raise any flags' - I'd rather you know and ask me, so I can tell you just what I am telling you.

'The electrician doesn't know what you want'

It's you who I want to know about this, the electrician should already know about this. There is nothing for the electrician to do regarding that right now - this is letting you know not to go in your panel and start moving things around, get an electrician for that.

We, HIs, should not be afraid to raise issues which will raise questions and make our clients more informed, least they go down to one of the Big Box stores and are told 'It's easy - just remember that white goes to white, black goes to black, and green goes to green, you can't go wrong that way' (I've heard them say that, and you CAN 'go wrong' that way.)

Originally Posted by Gunnar Alquist

As I tried to indicate, I will look for the dishwasher/disposal circuits without handle ties and I will try to identify multi-wire circuits that are on the same leg (tester reads 0 instead of 240 volts across the two legs) because this will overload the single neutral. I find improperly wired circuits once or twice a month.

Gunnar,

That is a very good thing to do. And, as you've stated, it shows how many are either done incorrectly by the electricians or by homeowners moving things around in their panels.

It only takes a little more time to start at the conduit/12-3 NM entries and follow those conductors (red and black) to their breakers, then measure the voltage between them.

Typically, you will only see 12-3 on either 240 volt circuits or on multi-wire circuits, *either* should measure 240 volts between the breakers they are connected to, *neither* should measure -0- volts.

Usually, the dishwasher and disposal are on the same yoke and would require a handle or an internal trip breaker, sometimes, though, the electrician will install separate receptacle outlets for them, still on multi-wire circuit, and no handle tie would be required then.

Point being, though, is that it is best to check the above, and it does not take much more time while you already have the panel cover off and are already looking into the panel.

Originally Posted by Jerry Peck

It would not hurt to advise your client that the panel has one or more (in this case all or almost all) circuits which are multi-wire and that extreme care should be used when they are anyone else is attempting to do any work in the panel, extreme care meaning that the multi-wire circuits should not be relocated without knowing what a multi-wire circuit is and what is required of a multi-wire circuit (i.e., that a multi-wire circuit is two 120 volt circuits, wired as a single 240 volt circuit with a neutral, and with *NO* 240 volt loads allowed on that circuit).

I routinely include a similar advisory comment in my report whenever I find a multi-wire branch circuit in a panel, even if there is no reportable defect with the installation. When the handles are not tied together and not required to be tied together, I recommend it be done as a safety improvement. I further recommend that such a change can be made when the electrician is at the home doing other repairs on the system. When the handles are required to be tied together I report it as a defect that requires repair.

With regards to phone calls, I think a lot of that comes down to how you communicate the implications of the issue to your client during the inspection and in your report.

Thanks, that clarifies an answer to my original question about what to say to the client. I will include comments about multi-wired circuits in the future, but ultimately stress the need for an electrical contractor for any work done in the panel, regardless if multi-wired circuits exist (which I do anyway). I haven't made up my mind about testing for loads, maybe I'll leave it for an electrician. I had a client recently who stuck their hand in the panel and almost touched the breaker before I stopped them. I need to keep my attention on the client when the panel cover is off even after warning them not to stick their hands in! Thanks again.

Originally Posted by Dave Mortensen

I had a client recently who stuck their hand in the panel and almost touched the breaker before I stopped them. I need to keep my attention on the client when the panel cover is off even after warning them not to stick their hands in!

Dave,

Use this: (underlining is mine)

- 110.26 Spaces About Electrical Equipment.
- - (B) Clear Spaces. Working space required by this section shall not be used for storage. When normally enclosed live parts are exposed for inspection or servicing, the working space, if in a passageway or general open space, shall be suitably guarded.

Get 4 rubber cones, some warning tape, set the cones up around the 'working space' you will be in, string the tape from cone to cone to cone to cone, marking off the 'working space'. Tell your client that only you are allowed in that working space with the panel cover off.

Wow! OK, thanks Jerry. A dunce cap wouldn't be a bad idea sometimes either...

Good point Gerry. The bulk of panels I see either have no circuits labeled in the Service Panel at all or they were marked once but now do not match the existing breaker configuration. In that case I have to err on the side of the fact that a 3 wire circuit MAY be service for different equipment on a single yoke device somewhere. Thus it gets written up as needing attention by a licensed electrician for a handle tie. And yes, the lack of labels gets written up too, guys.

If the breakers of a 3 wire circuit are attached to the same bus bar, that takes precedence over a possible lack of a handle tie problem even and is an immediate deferral to sparky.

Fritz, I cannot let your assertion pass. Using multiwire branch circuits is in no way "inherently less safe" than any other method. Is there another thing that can go wrong for the incompetent hack? Sure; but his troubles started - and his remedy lies - outside that panel cover.

In many wiring methods, one needs to consider "conduit fill." There are no advantages to filling the pipe with more wires than necessary. Indeed, the failure to use multiwire circuits can result in the wires operating at significantly higher temperatures. That's usually something to avoid. The use of such circuits is probably the main reason wire comes in so many different colors.

I once saw a bumper sticker that read "Remember when skydiving was dangerous - and sex was safe?" It's all a matter of training and PPE