Single Receptacle Question

[Paul Ternstrom]

The whole purpose of a handle tie on two or more circuit breakers is to turn off all poles if one trips "off". Several people have mentioned above that the handle tie does not trip "off" the other breaker. To me, that is a faulty handle tie. The definition of a MWBC is two (or three) individual 120V circuits that share a common neutral. That is why a handle tie is required when the two outlets share a common yoke, so that the "Two Circuits" are both "off" and no one gets bit by power still "on" if one breaker is "off". If you have the requirement for two single outlets (esp. where one cannot be turned off by the other, ie: an alarm), I would say the only solution would be to install two outlets on separate yokes along with a separate hot AND neutral to EACH outlet. This would be the only way they will be completely independent and unrelated.

 

[infinity]

The whole purpose of a handle tie on two or more circuit breakers is to turn off all poles if one trips "off". Several people have mentioned above that the handle tie does not trip "off" the other breaker. To me, that is a faulty handle tie.

I don't believe that the design of a handle tie would ensure that all of the single pole units tied together would simultaneously trip when only one breaker tripped. IMO it's simply unknown what will happen but if they don't all trip I wouldn't consider that handle items to be defective. It's purpose with a MWBC is to ensure that when turning off one breaker that all of them turn off.

Welcome to the Forum.

 

[don_resqcapt19]

The whole purpose of a handle tie on two or more circuit breakers is to turn off all poles if one trips "off". Several people have mentioned above that the handle tie does not trip "off" the other breaker. To me, that is a faulty handle tie. The definition of a MWBC is two (or three) individual 120V circuits that share a common neutral. That is why a handle tie is required when the two outlets share a common yoke, so that the "Two Circuits" are both "off" and no one gets bit by power still "on" if one breaker is "off". If you have the requirement for two single outlets (esp. where one cannot be turned off by the other, ie: an alarm), I would say the only solution would be to install two outlets on separate yokes along with a separate hot AND neutral to EACH outlet. This would be the only way they will be completely independent and unrelated.

The only purpose of a handle tie is to provide a means to manually shut off all ungrounded conductors of a multiwire circuit. There is no intention that a handle tie create a "common trip" like you have on a two or 3 pole breaker.
One manufacturer told me that their tests show a handle tie across two breakers will open both breakers when one trips about 50% of the time, but if you have a handle tie across 3 breakers, as trip on one breaker almost never opens the other two.

 

[electrofelon]

The whole purpose of a handle tie on two or more circuit breakers is to turn off all poles if one trips "off". Several people have mentioned above that the handle tie does not trip "off" the other breaker. To me, that is a faulty handle tie. .

That is not correct. A handle tie is not intended to, nor is it likely to in practice, turn off all the poles upon one tripping. A MWBC does not require common trip, unless it's serving two circuits on the same yoke.

 

[LarryFine]

Welcome to the forum.

The whole purpose of a handle tie on two or more circuit breakers is to turn off all poles if one trips "off".

While a handle tie might cause one pole tripping to take the other pole(s) with it, a true 2- (or 3-) pole breaker includes a mechanical link between the mechanisms (internal common trip) that assures it will.

Even if you removed the handle tie of a multi-pole breaker, one pole tripping will open all poles. The handle tie is only for simultaneous manual operation.

 

[don_resqcapt19]

That is not correct. A handle tie is not intended to, nor is it likely to in practice, turn off all the poles upon one tripping. A MWBC does not require common trip, unless it's serving two circuits on the same yoke.

Still only requires a handle tie for that application as the rule in 210.7 requires a means to simultaneously disconnect the ungrounded conductors.

 

[electrofelon]

Still only requires a handle tie for that application as the rule in 210.7 requires a means to simultaneously disconnect the ungrounded conductors.

Ok thanks. I am thinking of something else I think. Maybe a MWBC that serves a line to line load?

 

[Another C10]

Is a duplex receptacle fed with 12-3, with the hot tab removed, supplied by a 2 pole breaker considered two single receptacles on a MWBC?

well ... a duplex receptacle is 2 receptacles as indicated by the word duplex. I guess it depends on how much time you want to spend arguing with an inspector.

 

[infinity]

well ... a duplex receptacle is 2 receptacles as indicated by the word duplex. I guess it depends on how much time you want to spend arguing with an inspector.

Correct but it is still not two single receptacles.

 

[Paul Ternstrom]

Ok thanks. I am thinking of something else I think. Maybe a MWBC that serves a line to line load?

By definition (NEC Art 100, Branch Circuit, Multiwire) a MWBC is two or more hot conductors that share a common neutral. Line to line loads are not a multiwire branch circuit.

 

[don_resqcapt19]

By definition (NEC Art 100, Branch Circuit, Multiwire) a MWBC is two or more hot conductors that share a common neutral. Line to line loads are not a multiwire branch circuit.

The code permits a multiwire branch circuit to supply line to line loads in one utilization equipment. See EX 1 to 210.4(C).

 

[Paul Ternstrom]

That is not correct. A handle tie is not intended to, nor is it likely to in practice, turn off all the poles upon one tripping. A MWBC does not require common trip, unless it's serving two circuits on the same yoke.

Art. 210.4(B) in the 2005 NEC had the requirement for a common trip when devices were on the same yoke, but that section was changed in the 2008 NEC to include all MWBC to have the common trip, with no mention if the devices were on a common yoke or not. Whenever the neutral is shared between two hot conductors, there can be a danger of voltage on the shared neutral conductor if any one of the hot circuits is turned "off" and the other circuits are left "on".

 

[roger]

Art. 210.4(B) in the 2005 NEC had the requirement for a common trip when devices were on the same yoke, but that section was changed in the 2008 NEC to include all MWBC to have the common trip, with no mention if the devices were on a common yoke or not. Whenever the neutral is shared between two hot conductors, there can be a danger of voltage on the shared neutral conductor if any one of the hot circuits is turned "off" and the other circuits are left "on".

Read 210.4(B) closely and you will see there is no mention of "common trip"

(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.

 

[roger]

By definition (NEC Art 100, Branch Circuit, Multiwire) a MWBC is two or more hot conductors that share a common neutral. Line to line loads are not a multiwire branch circuit.

How would you define a Range or Dryer circuit? They both use a neutral and feed L-L loads as well.

 

[Paul Ternstrom]

The code permits a multiwire branch circuit to supply line to line loads in one utilization equipment. See EX 1 to 210.4(C).

210.4(C) refers to Line to Neutral loads. I believe this exception would cover a piece of equipment like a clothes dryer, where the load is basically a line to line load (where you would already have a multi-pole CB) but there is a neutral also provided to give 120V power for the controls, light, etc. in the dryer. It would still be considered a MWBC (by definition) because of the shared neutral conductor.

 

[Paul Ternstrom]

Read 210.4(B) closely and you will see there is no mention of "common trip"

Is there another way to "simultaneously disconnect all ungrounded conductors" without a common trip?

 

[roger]

Is there another way to "simultaneously disconnect all ungrounded conductors" without a common trip?

Yes, handle ties which may or may not trip both.

 

[roger]

210.4(C) refers to Line to Neutral loads. I believe this exception would cover a piece of equipment like a clothes dryer, where the load is basically a line to line load (where you would already have a multi-pole CB) but there is a neutral also provided to give 120V power for the controls, light, etc. in the dryer. It would still be considered a MWBC (by definition) because of the shared neutral conductor.

Correct.

 

[LarryFine]

Is there another way to "simultaneously disconnect all ungrounded conductors" without a common trip?

Yes, the handle tie we're discussing, which is for opening all poles during manual operation.

The "common trip" refers to the internal mechanism that opens all poles during a short/overload.

Manual operation is not "tripping."

 

[jap]

My thoughts are, a handle tie is nothing more than a visual indication of what all breakers are associated with a shared neutral.

It has nothing to do with common tripping all the individual breakers associated with the tie.

Nor is the handle tie associated with simultaneously disconnecting all of the ungrounded conductors.

Simultaneously disconnecting all of the conductors associated with the handle tie is dependent on on my hand positioning when I go to shut them off, not the tie itself.

JAP>