My registeration expired or i could not use my existing ID and/or password so i had to register again.

My ispection was failed because the inspector said all multiwire branch circuit that share a neutral must be on a tied breaker.

In my situation i had two single breakers on two different busbars feeding two receptacles for garebage disposer and the washing machine.

My understanding is whenever there is a peotential difference between the ungrounded conductors on one device then the breaker has to be tied.

Is he correct in his statement?

Thanks
Edward

In my opinion he is incorrect. As long as the two breakers are on opposing poles of the panel buss there is no code violation until they are feeding a single yolk. If they are not feeding a single yolk device than they can be 1,3,5,7,9, etc spaces apart, but I would have them right next to each other.

Remember also that, when NOT using handle-tied breakers, that every neutral connection cannot depend on the receptacle screws, but must be joined, and terminals pigtailed.

Larry, I ALWAYS- ALWAYS make pigtails.

If you think the inspector is right or has an argument please give me a code reference i can not find any NEC reference that supports his statement.

Thanks
Edward

Edward

Did you mean disposal and dishwasher ? Are you feeding a single split wired duplex receptacle with this circuit? If you are feeding a split wired duplex with this circuit you need a handle tie or a 2 pole breaker. As long as both of these circuits do not connect to a single device (yoke) you don’t need a handle tie or 2 pole breaker.

What city is this in?

Curt

Curt,

It is San Jose.

I always use two separate receptacles.
The inspector said everytime you have multiwire branch circuits and share a neutral, you must use tied breakers.

???????

Thankx
edward

I'm sure this was a combo inspector. Call the city and ask to speak with the electrical supevisor for the area your project is in. Don't change the breaker just to make him happy.

Curt

The flat I just moved out of had this configuration- common duplex receptacle feeding a dishwasher and a disposal, two circuits, handle tied. For me, it makes sense because this way you won't run into a half-dead box assuming it's fully dead.

This applies handle ties or not.

Right you are!

300.13 Mechanical and Electrical Continuity — Conductors.

(B) Device Removal. In multiwire branch circuits, the continuity of a grounded conductor shall not depend on device connections such as lampholders, receptacles, and so forth, where the removal of such devices would interrupt the continuity.

[This message has been edited by Larry Fine (edited 08-18-2006).]

210.4 (B)

But that's assuming that the garbage disposer and laundry receptacle are both on the same yoke (same duplex receptacle).

Shockme,

My situation is that i have used two separate duplex receptacles(separate yokes) for the GB and the DW.

The inspector says " anytime yo have multiwire circuits with shared neutral (regardless of being on the same yoke or not)you have to use tied breakers.

Edward

Nikko, ask him to show you where in the code. He won't be able to.

Until 2008

Thank you for your replies.

Nikko, I must have misunderstood (or misread) your situtation. I used to have a boss who would make us install double pole circuit breakers whenever we used multiwire branch circuits. Me and another guy used to argue about it with him until one day we just gave up trying to convince him that it didn't need to be done. He told us both that it was his liability insurance and not ours. Now I work for a guy who prefers that I do not use 3-wire branch circuits even though in the end it'll save a few bucks and perhaps 'that' money could be going into my pockets!

I believe this is what IWIRE refers to

210.4 Multiwire Branch Circuits.
(A) General. Branch circuits recognized by this article
shall be permitted as multiwire circuits. A multiwire circuit
shall be permitted to be considered as multiple circuits. All
conductors of a multiwire branch circuit shall originate
from the same panelboard or similar distribution equipment.
[ROP 2–10]
FPN: A 3-phase, 4-wire, wye-connected power system
used to supply power to nonlinear loads may necessitate
that the power system design allow for the possibility of
high harmonic neutral-conductor currents. [ROP 2–11]
(B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates. [ROP 2-10]

very interesting!!

Charlie

[This message has been edited by cpal (edited 08-20-2006).]

You nailed it Charlie.

As a big fan of multiwire branch circuits I do not support this change.

I am hoping that the MA amendments will remove this protection for the unqualified.

Bob

Bob
As you know there is still time to submit a concern through the comment stage the pre print and ROP are not written in stone.

I will have a better feel for the MAss Amendments some time in late September.

Charlie

At least it will allow handle-ties, and need not necessarily be a common-trip unit.

" As long as the two breakers are on opposing poles of the panel buss there is no code violation"

Mike, while I'm sure everyone agrees that is a good practice, is it actually stated in the code as a requirement? Don't get me wrong, I always put them on opp legs, but what would be the violation if say it was 2 dedicated ckts with the total load on all conductors, neutral included, within their ampacity?

210.19 (A) (2) Multioutlet Branch Circuits. Conductors of branch
circuits supplying more than one receptacle for cord-andplug-
connected portable loads shall have an ampacity of
not less than the rating of the branch circuit.

This language may be a problem if the neutral capacity is not increased

Charlie

quote" Mike, while I'm sure everyone agrees that is a good practice, is it actually stated in the code as a requirement? Don't get me wrong, I always put them on opp legs, but what would be the violation if say it was 2 dedicated ckts with the total load on all conductors, neutral included, within their ampacity?"

BigB you are correct here there would not be one in that situation. However then it would not actually be a multiwire branch circuit, but two circuits sharing a grounded conductor. NEC 100-1

[This message has been edited by macmikeman (edited 08-22-2006).]

It is very difficult to find a handle tie that ties circuit breakers in positions 1, 4 and 42 together.

I seen alot of #12 Solid as a handle tie, maybe if you bent it just so...

The picture that this conjures up in my mind gave me a good chuckle. Thanks a lot.

[This message has been edited by tdhorne (edited 09-16-2006).]

True, but I always place shared-neutral MWBC's on adjacent breakers to minimize the chance of overloading the neutral.

Well I prefer to place them side by side but I don't always.

The NEC does not require them to be side by side.

Regardless none of my neutrals will be overloaded unless someone changes the locations after I leave.

Definitions, Article 100: "Branch Circuit, Multiwire. A branch circuit that consists of two or more ungrounded conductors that have a voltage voltage between them and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system."

To meet this definition, we must use phases A and B (and maybe C too).

earlydean- You are 100% correct and I will say they will need to be side by side by side. I know there aren't any words that say they need to be so physically located but that is just too easy to figure out. If they are to be simultaneously tripped that's the only way this hard nosed inspector will accept them. (Sorry Bob)

Edited causs I can't spill



[This message has been edited by George Little (edited 09-18-2006).]

I'm glad I never had this fight. I really like them common trip, no matter where they go and the installers I worked with had the same opinion ... but they were generally the same guys who would "own" this installation after I left. I have OKed the #12 copper "tie" tho.

George,
I think that is where some people get confused. A "multiwire circuit" is, for example, a range outlet. It has to be fed with a multipole breaker, on different phases, which opens the two circuits simultaneously. These of course have to be side by side.
A "multiwire branch circuit" is more than one circuit, of different phases, sharing a neutral. For example, general purpose lighting and receptacle loads. These do not have to be side by side in the panel, and do not have to be opened simultaneously.

The code does address multiwire circuits that also have line to line loads and they are required to be common trip breakers. The real question is a MW that only has line to neutral loads.
I imagine all MW with require common trip some day if the code keeps going the way it does.
Eaton and SqD gotta eat too.

I was trying to make the point that if a multiwire branch circuit is to be disconnected simultaniously then it either needs to be a common trip breaker or multiple breakers that are side by side and tied together via a "Listed" handle tie. Unless of course you are in Florida.
(gfretwell territory)

Just jerking your chain Greg.

[This message has been edited by George Little (edited 09-20-2006).]

I may be a rebel but I think a 12 ga wire "formed" around the ends of the breaker handles is a better tie than that little pointy ended thing SqD sells. You sure don't lose it when you disturb the breakers.

Greg- I think a properly sized nail or a piece of #10 wire workes better than those sq D handle ties for sure and I agree with you. And you are also right- you are a rebel.