210.4 (B) Multiwire branch Circuit Disconnecting Means

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kenaslan

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Discussion here in the office in regards to 210.4 (B)

I believe that ALL multiwire branch circuits shall simultaneously disconnect REGARDLESS if a shared neutral (grounded conductor) or dedicated neutrals are in the cable.

Some here believe that if there are dedicated neutrals per each circuit, that single pole breakers are fine instead of simultaneous disconnecting of both circuits.
 
kenaslan said:
Discussion here in the office in regards to 210.4 (B)

I believe that ALL multiwire branch circuits shall simultaneously disconnect REGARDLESS if a shared neutral (grounded conductor) or dedicated neutrals are in the cable.

Some here believe that if there are dedicated neutrals per each circuit, that single pole breakers are fine instead of simultaneous disconnecting of both circuits.
Click to expand...

If you have a dedicated neutral per circuit then you don't have a MWBC.

JAP>
 
If they do not share a neutral, how would they be a MWBC?


Branch Circuit, Multiwire. A branch circuit that consists of two or more ungrounded conductors that have a voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system.

A cable with 2 individuals circuits is not really different than 2 separate circuits in a raceway.
 
kenaslan said:
Discussion here in the office in regards to 210.4 (B)

I believe that ALL multiwire branch circuits shall simultaneously disconnect REGARDLESS if a shared neutral (grounded conductor) or dedicated neutrals are in the cable.

Some here believe that if there are dedicated neutrals per each circuit, that single pole breakers are fine instead of simultaneous disconnecting of both circuits.
Click to expand...


I agree with Jap. By definition a multiwire branch circuit shares a neutral. Why would you require a multipole breaker for circuits that have their own neutrals?
 
480sparky said:
By definition, it's not a multi-wire, but to answer your question: if you had two hots and two neutrals going to a duplex receptacle.
Click to expand...

Yes, but that is because of the equipment it serves, not the circuits themselves.

If the cable served 2 different individual/separate duplexes, you would not need a handle tie or 2 pole breaker.

I am really posting this for OP even though I quoted you.

I realize you know this already.
 
Yes, however the discussion now is if a terminal strip in a junction box or equipment counts as "Same yoke or mounting strap". My vote is that it is, unless the intent is for something else. I prefer when shutting off power to equipment, all sources from the same panel are simultaneously disconnected.
 
480sparky said:
By definition, it's not a multi-wire, but to answer your question: if you had two hots and two neutrals going to a duplex receptacle.
Click to expand...
Jumper said:
Yes, but that is because of the equipment it serves, not the circuits themselves.

If the cable served 2 different individual/separate duplexes, you would not need a handle tie or 2 pole breaker.

I am really posting this for OP even though I quoted you.

I realize you know this already.
Click to expand...
Both correct but just to clarify a bit further if you had a MWBC (where a neutral is being shared) then a 2-P breaker has to be used 210.4(B). If you have a situation like Jumper cited where you ran say two-2 conductor NMC's into a JB and those circuits started out on opposing phases and then you attached the load ends to a duplex receptacle where you snapped off both the side tabs on the receptacle then you would also have to use a 2-P breaker as Roger cited (210.7) because the opposing phases would be attached to the same yoke.

Now, if you had a cable assembly that had two neutrals and two line voltage conductors and you attached them to two separate duplex receptacles in one junction box then you would not need a 2-P breaker. In addition, they don't have to be attached to opposing phases.

If I'm wrong someone please correct me.
 
goldstar said:
Both correct but just to clarify a bit further if you had a MWBC (where a neutral is being shared) then a 2-P breaker has to be used 210.4(B). If you have a situation like Jumper cited where you ran say two-2 conductor NMC's into a JB and those circuits started out on opposing phases and then you attached the load ends to a duplex receptacle where you snapped off both the side tabs on the receptacle then you would also have to use a 2-P breaker as Roger cited (210.7) because the opposing phases would be attached to the same yoke.

Now, if you had a cable assembly that had two neutrals and two line voltage conductors and you attached them to two separate duplex receptacles in one junction box then you would not need a 2-P breaker. In addition, they don't have to be attached to opposing phases.

If I'm wrong someone please correct me.
Click to expand...

I think your pretty well right.

JAP>
 
goldstar said:
Both correct but just to clarify a bit further if you had a MWBC (where a neutral is being shared) then a 2-P breaker has to be used 210.4(B). If you have a situation like Jumper cited where you ran say two-2 conductor NMC's into a JB and those circuits started out on opposing phases and then you attached the load ends to a duplex receptacle where you snapped off both the side tabs on the receptacle then you would also have to use a 2-P breaker as Roger cited (210.7) because the opposing phases would be attached to the same yoke.

Now, if you had a cable assembly that had two neutrals and two line voltage conductors and you attached them to two separate duplex receptacles in one junction box then you would not need a 2-P breaker. In addition, they don't have to be attached to opposing phases.

If I'm wrong someone please correct me.
Click to expand...

Looks correct to me.
 
kenaslan said:
Yes, however the discussion now is if a terminal strip in a junction box or equipment counts as "Same yoke or mounting strap". My vote is that it is, unless the intent is for something else. I prefer when shutting off power to equipment, all sources from the same panel are simultaneously disconnected.
Click to expand...

A terminal strip is not the same as a device yolk and you do not have to kill power to all of it. It's a design issue.
 
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