Pigtailed neutrals on MWBC

[ptonsparky]

Can someone point me to the section that requires neutrals on MWBC be pigtailed out to the receptacles?

"Because I said so." won't work today.

Thanks

 

[david luchini]

Can someone point me to the section that requires neutrals on MWBC be pigtailed out to the receptacles?

"Because I said so." won't work today.

Thanks

I think you're looking for 300.13(B).

 

[jumper]

I think you're looking for 300.13(B).

Yep.


(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.

 

[ptonsparky]

Yep.


(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.

Would this come into play when a garbage disposal and dishwasher are connected to the same yoke? I did not open things up but the second neutral connection from the device screws extended on up to the box enclosing the GD switch. Probably connected to nothing, but if it is a lighted switch. IDK. Possible there is a receptacle on the backside of the island. I didn't look.

 

[david]

Would this come into play when a garbage disposal and dishwasher are connected to the same yoke? I did not open things up but the second neutral connection from the device screws extended on up to the box enclosing the GD switch. Probably connected to nothing, but if it is a lighted switch. IDK. Possible there is a receptacle on the backside of the island. I didn't look.

I would not assume the garbage disposal and dish washer are feed with 12/3 a multi-wire branch circuit.

The garbage disposal and dishwasher may be feed with two sets of 12/2 and still land on the same yoke

Both the hot and neutral tabs would be split for the two sets of 12/2. If they are feed with a 12/3 multi-wire circuit the neutrals may be pig tailed and the neutral tab broken or a single neutral could land on the the receptacle with out breaking the neutral tab

but with the same yoke you need a handle tie for the breakers supplying the device on the same yoke

 

[ptonsparky]

It is a true MWBC.

 

[david]

Can someone point me to the section that requires neutrals on MWBC be pigtailed out to the receptacles?

"Because I said so." won't work today.

Thanks

To answer your question directly, your branch circuit is not being daisy chained through that rec. there is no issue affecting the continuity of the neutral at the garbage disposal and dish washer to require the neutral at that location to be pig tailed to that device (rec.)

 

[david]

Would this come into play when a garbage disposal and dishwasher are connected to the same yoke? I did not open things up but the second neutral connection from the device screws extended on up to the box enclosing the GD switch. Probably connected to nothing, but if it is a lighted switch. IDK. Possible there is a receptacle on the backside of the island. I didn't look.

Are you sure the white conductor you see going to the GD switch is a neutral or is it part of the sw loop

 

[ptonsparky]

Yes, it’s a neutral. A three wire heads that way, with a red switch leg coming back to the switched half of the outlet

 

[jap]

Yes, it’s a neutral. A three wire heads that way, with a red switch leg coming back to the switched half of the outlet

If that's the case then you only have 1 circuit heading up to the switch from the receptacle not 2, and there is no need to pigtail the neutrals in the receptacle, box although I always do anyway.

JAP>

 

[ptonsparky]

It is a multiwire branch circuit. The Black feeds half of the duplex, the Red feeds the other half after it goes to a switch and returns. Two different CBs, one on each leg. 240 between the hots. 120 hots to neutral.

 

[jap]

It is a multiwire branch circuit. The Black feeds half of the duplex, the Red feeds the other half after it goes to a switch and returns. Two different CBs, one on each leg. 240 between the hots. 120 hots to neutral.

Yes it is, but, it is not 2 circuits up to the switch, so, pig tailing the neutral prior to the switch location is not required, even if that one circuit extends beyond the switch location.

It is still only 1 circuit and opening the neutral at the receptacle before it gets to the switch location or beyond is not going to affect the circuit like opening the neutral on an extension of 2 circuits where the neutral is shared would.


JAP>

 

[jap]

If it's wired as you say, then , you only have one 120v circuit in the switch box.

The red circuit.

Red circuit comes into the receptacle box, the red wirenuts to the black in the 12/3 to the swich, switchleg back from the switch on red which terminates on the receptacle.

JAP>

 

[al hildenbrand]

Yes, it’s a neutral. A three wire heads that way, with a red switch leg coming back to the switched half of the outlet

The language in 300.13(B) is only interested in "continuity" of the grounded conductor, not whether there is any current flowing. Removal of device connections cannot interrupt "continuity" of the grounded conductor. That is the rule of 300.13(B).

 

[jap]

There was a graphic floating around somewhere that showed the neutral not needing to be pigtailed once it got pass the need of the 2 separate circuits.

Otherwise, if you talking about continuity, you could never use the back stabs for daisy chaining in any circumstance.

JAP>

 

[jap]

In the OP's case, the continuity of a MWBC would not be interrupted because the extension to the switch and back is not a MWBC.

JAP>

 

[al hildenbrand]

If that's the case then you only have 1 circuit heading up to the switch from the receptacle not 2, and there is no need to pigtail the neutrals in the receptacle, . . .

To me, that's a hard sell. A multiwire branch circuit is "1 circuit." Once the grounded conductor is common, the two hots become a single multiwire branch circuit.

 

[al hildenbrand]

In the OP's case, the continuity of a MWBC would not be interrupted because the extension to the switch and back is not a MWBC.

The rule is ONLY about the continuity of the grounded conductor, not the MWBC.

 

[jap]

To me, that's a hard sell. A multiwire branch circuit is "1 circuit." Once the grounded conductor is common, the two hots become a single multiwire branch circuit.

Yes your correct, but it is not a MWBC from the receptacle up to the switch, which is the key factor and what the wording of 300.13(B) is tailored towards.
Ahead of the receptacle Yes you must pigtail because the grounded conductor is shared.
In this case, the grounded conductor is not shared beyond the receptacle because there is not 2 circuits extending past the receptacle.


JAP>

 

[al hildenbrand]

In this case, the grounded conductor is not shared beyond the receptacle because there is not 2 circuits extending past the receptacle.

I'll admit, this scenario, with a garbage disposal switch being at the end of the extension from the duplex receptacle outlet makes this a little hard to talk about without getting over into "is a switch an outlet?". . . I don't want to sidetrack into that, to be very clear.

The thing I have trouble with, with thinking about a single energized conductor and the grounded conductor extending from the duplex receptacle outlet box, is how a single MWBC becomes multiple circuits. . . The definition (in Article 100) of a MWBC is that it is "a branch circuit. . . " And the definition of Branch Circuit is the wiring from the final OCPD to the Outlets.

So, a MWBC exists from the final OCPD to the Outlets . . . "to the Outlets", not to some arbitrary Outlet in the middle of other Outlets.

Although I "know" the hazard of the voltage swings related to an Open Neutral, the NEC language of 300.13(B) and the Definitions DON'T include anything more than "continuity" of the grounded conductor. I can't see how the language can be excluded from covering the neutral that is extended with only one energized conductor, as it is written.

Here: put it another way. What you want to call "1 circuit" (hot and neutral) is an extension from "1 circuit" (MWBC) . . . and the grounded conductor throughout has to follow 300.13(B), IMO.