Pigtailed neutrals on MWBC

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jap said:
If we remove the device in this scenario and that neutral up to the switch doesn't go any further, we're simply left with a spare MWBC under the sink.
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The problem with interpreting 300.13(B) by just looking at which sections of the circuit are MWBCs after removal of the device is that such an interpretation would not require pigtailing in the Mike Holt graphic. There's no way to interpret the text of 300.13(B) to require pigtailing in the Mike Holt graphic situation but not require it in the OP's situation. I agree they are electrically different situations, but the text does not distinguish.

Cheers, Wayne
 
al hildenbrand said:
What? "a spare MWBC"? ? Where's the second MWBC?
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Yes, a spare MWBC.

If you take the receptacle out in this original post and the neutral we've been talking about since post #1 that's coming from this receptacle to the GD Switch is capped off in the GD switch box , then your left with a black red white and bare ground in a box under the sink not going to anything.

Hence, a spare MWBC already installed under the sink should you need it for something else.

JAP>
 
jap said:
Hence, a spare MWBC already installed under the sink should you need it for something else.
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Oh. :dunce:

Well, OK. But what you are calling spare is not the original installation. Even with the OP scenario receptacle device removed and all individual conductors capped off, the garbage disposal and the dishwasher are still present and their cords are still present.

Kinda meaningless to say the MWBC is now "spare", when the appliances are sitting right there. . . .
 
al hildenbrand said:
Oh. :dunce:

Well, OK. But what you are calling spare is not the original installation. Even with the OP scenario receptacle device removed and all individual conductors capped off, the garbage disposal and the dishwasher are still present and their cords are still present.

Kinda meaningless to say the MWBC is now "spare", when the appliances are sitting right there. . . .
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Now that just doesn't make any sense whatsoever.

Nothing needs to be plugged into a MWBC to make it one.

C'mon Al. :D

JAP>
 
jap said:
Now that just doesn't make any sense whatsoever.

Nothing needs to be plugged into a MWBC to make it one.

C'mon Al. :D

JAP>
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The existential existence of the MWBC itself has never been in question.:happyno:
 
Maybe you can allow that the receptacle device is removed for the purpose of replacement? Eh? Nudge, nudge.
 
al hildenbrand said:
Oh. :dunce:

Even with the OP scenario receptacle device removed and all individual conductors capped off, the garbage disposal and the dishwasher are still present and their cords are still present.

Kinda meaningless to say the MWBC is now "spare", when the appliances are sitting right there. . . .
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I think I'll just leave it with this parting thought.


JAP>:happyno:
 
MWBC

MWBC

LarryFine said:
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That's why I believe the pigtail is required in this example: technically speaking, the multi-wire circuit extends "through" the box (like when you say 'one through ten'), even though it also ends in the box.

Opening the neutral with both appliances operating places them in series across 240, and creates a shock hazard with either in use. I realize that that's why multi-wire circuits require tied breakers.
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I am with you Larry, "Extends through" is the correct interpretation. Mike's diagram doesn't show a tied handle disconnect in a MWBC circuit feed. In addition, the circuits shown are not compliant to NEC 2014, 2017 Sections 210.8 and 210.12 fault protection. The MWBC circuit regardless of pigtailing will cause the AFCI-GFCI OCPD(s) to trip out when loads become energized.
 
gndrod said:
Spot on. In addition, he should also be looking for 210.7 if the MWBC is running two branch circuits having a shared neutral to the same yoke require a tied common handle?
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MWBC's require handle ties regardless, many years ago that wasn't always required though.

210.7 is saying a handle tie is required any time multiple circuits land on the same device on a common yoke. So if you ran 2 - two wire circuits to a duplex receptacle - the branch circuits themselves isn't a MWBC and doesn't require handle ties, but the fact they land on same yoke still means you need a handle tie.
 
MWBC

MWBC

kwired said:
MWBC's require handle ties regardless, many years ago that wasn't always required though.

210.7 is saying a handle tie is required any time multiple circuits land on the same device on a common yoke. So if you ran 2 - two wire circuits to a duplex receptacle - the branch circuits themselves isn't a MWBC and doesn't require handle ties, but the fact they land on same yoke still means you need a handle tie.
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Thank you for confirming my statement and what Larry has basically mentioned in his post 79.
 
gndrod said:
Thank you for confirming my statement and what Larry has basically mentioned in his post 79.
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You read what you wanted to read and not what I said.

What I said was that 210.7 isn't about MWBC's and shared neutrals, but rather that any single yoke device with multiple circuits connected to it must have handle ties between the supply circuits.

I also said that MWBC's require handle ties whether they are going to a common yoke or not. Years ago that wasn't always the rule, but was the rule when landing on same yoke.

I was not trying to insult you or Larry or prove you wrong, I was trying to provide additional information/clarification on the subject.
 
MBC

MBC

kwired said:
You read what you wanted to read and not what I said.

What I said was that 210.7 isn't about MWBC's and shared neutrals, but rather that any single yoke device with multiple circuits connected to it must have handle ties between the supply circuits.

I also said that MWBC's require handle ties whether they are going to a common yoke or not. Years ago that wasn't always the rule, but was the rule when landing on same yoke.

I was not trying to insult you or Larry or prove you wrong, I was trying to provide additional information/clarification on the subject.
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No problem here either. Relating to MWBC vs. MBC is probably what causes frustrations in mind all the time and I apologize if using MWBC did dissect the intent. Definitely there is a difference and you are correct. Given that 210.7 does relate directly to MBC's wiring to a common yoke, the original post does not really indicate the origin having 12-3 nor 12-4 or better wire quantities. The importance of 300.13(B) neutral pigtailing involves having a common handle/tie of 210.7 not mentioned early in this discussion. The originating multiple circuit disconnects and wiring should be included for the receptacle configuration in question as it does affect the key importance of requiring 210.7 safety.

I realize the strain of code definition does have the fine line that we all strive to accomplish and I support your efforts to do so. At this point, I believe Tom mentioned that he was not privy to the circuit conductor combined quantities that define the branch circuits discussed. I do agree.
 
gndrod said:
No problem here either. Relating to MWBC vs. MBC is probably what causes frustrations in mind all the time and I apologize if using MWBC did dissect the intent. Definitely there is a difference and you are correct. Given that 210.7 does relate directly to MBC's wiring to a common yoke, the original post does not really indicate the origin having 12-3 nor 12-4 or better wire quantities. The importance of 300.13(B) neutral pigtailing involves having a common handle/tie of 210.7 not mentioned early in this discussion. The originating multiple circuit disconnects and wiring should be included for the receptacle configuration in question as it does affect the key importance of requiring 210.7 safety.

I realize the strain of code definition does have the fine line that we all strive to accomplish and I support your efforts to do so. At this point, I believe Tom mentioned that he was not privy to the circuit conductor combined quantities that define the branch circuits discussed. I do agree.
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What are you referring to when you use the abbreviation MBC ?

JAP>
 
I don't know that MBC is used as an abbreviation for Multiple Branch Circuits if that is what's mean by it.

JAP>
 
jap said:
What are you referring to when you use the abbreviation MBC ?

JAP>
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He is talking about 210.7 - which is titled "multiple branch circuits".

Apparently I stirred the pot some when I tried to point out that 210.7 not only applies to MWBC's but also anytime multiple branch circuits are all connected to a single device. MWBC's require handle ties even if they are not connected to a single device so is a little redundant to even mention them in 210.7.
 
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