Handle Ties

[Richard Robinson]

This might be an easy one but can anyone cite a verse in the NEC that states handle ties are or are not legal when required by 210.4(B)?

[Brad Richter]

2011 NEC 240.15(B)(1)

[Jerry Peck]

This might be an easy one but can anyone cite a verse in the NEC that states handle ties are or are not legal when required by 210.4(B)?


2011 NEC 240.15(B)(1)

And you are supporting the "are" or the "are not" "legal" part of the question?

[Richard Robinson]

And you are supporting the "are" or the "are not" "legal" part of the question? Finding that they are legal in single phase applications, only our Herman Miller cubicles are all three phase so I guess I will have to break the news that future modifications are going to be more difficult.

[Jerry Peck]

Finding that they are legal in single phase applications, only our Herman Miller cubicles are all three phase so I guess I will have to break the news that future modifications are going to be more difficult.

Handle ties are legal for single phase and 3-phase, each with provisions.

First and foremost is that the handle ties have to be identified (presumably, applying 110.3(B), that means for the breakers they are used on), and they also have to be such that when one breaker trips all the tied-together-with-handle-ties breakers must trip (those old Square D ones which were short aluminum rods with turned down spindle ends typically did not accomplish that).

240.15(B)(1) addresses single-phase multiwire branch circuits with single-pole breakers and which serve only line-to-neutral loads (which is what a multiwire branch circuit does).

240.15(B)(2) addresses single-phase 120/240 volt circuits with single-pole breakers which serve line-to-line single-phase circuits (regular 240 volt circuits).

240.15(B)(3) addresses 3-phase and 2-phase 120/240 volt circuits with single-pole breakers which serve line-to-line circuits as long as there is a grounded neutral point and the voltage does not exceed 120 volts to ground.

240.15(B)(4) addresses 3-wire DC circuits. nut which is not likely to be encountered by home inspectors, except possibly DC PV circuits from PV solar systems.

Anyway, the point is that 3-phase is not a prohibited use - just limited to what is addressed ... as the other uses are.

[Richard Robinson]

Handle ties are legal for single phase and 3-phase, each with provisions.

First and foremost is that the handle ties have to be identified (presumably, applying 110.3(B), that means for the breakers they are used on), and they also have to be such that when one breaker trips all the tied-together-with-handle-ties breakers must trip (those old Square D ones which were short aluminum rods with turned down spindle ends typically did not accomplish that).

240.15(B)(1) addresses single-phase multiwire branch circuits with single-pole breakers and which serve only line-to-neutral loads (which is what a multiwire branch circuit does).

240.15(B)(2) addresses single-phase 120/240 volt circuits with single-pole breakers which serve line-to-line single-phase circuits (regular 240 volt circuits).

240.15(B)(3) addresses 3-phase and 2-phase 120/240 volt circuits with single-pole breakers which serve line-to-line circuits as long as there is a grounded neutral point and the voltage does not exceed 120 volts to ground.

240.15(B)(4) addresses 3-wire DC circuits. nut which is not likely to be encountered by home inspectors, except possibly DC PV circuits from PV solar systems.

Anyway, the point is that 3-phase is not a prohibited use - just limited to what is addressed ... as the other uses are.It would appear that 240.15(B)(1) would appy in the case of our furniture that serves only Line to Neutral loads for office areas. In that case it states only single phase loads can be tied together? Found a pretty good article that discusses the proper use of handle ties on 2 breakers. 240.15(B)(3) discusses 3 Phase but it states line to line with a neutral. I see that as a 5 wire L21-20R with a matching plug or simular load with three phases that require a neutral.Blog - Newsroom - Newsroom - Communications - Independent Electrical Contractors (http://www.ieci.org/newsroom-and-insights/multi-wire-branch-circuits)(1) Multiwire Branch CircuitsIndividual single-pole circuit breakers, with identified handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only single-phase line-to-neutral loads.

[Brad Richter]

Most multipole circuit breakers have internal common trip mechanisms. If they don't they must be labeled as non-common trip. Individual circuit breakers with handle tie may or may not both trip upon an overload or short circuit. There is NO requirement that the handle ties provide common trip. The handle ties are required to manually shut of the breakers simultaneously on MWBC's.

From Scneider/Square D:

[Richard Robinson]

Most multipole circuit breakers have internal common trip mechanisms. If they don't they must be labeled as non-common trip. Individual circuit breakers with handle tie may or may not both trip upon an overload or short circuit. There is NO requirement that the handle ties provide common trip. The handle ties are required to manually shut of the breakers simultaneously on MWBC's.

From Scneider/Square D:
I guess I need to clarify the question, I is it legal for me to install a 3 Phase handle tie on 120V circuits that share a common Neutral when I can only find the code reference that states they are acceptable on Line to Neutral type Single phase circuits (2Pole)?

[Brad Richter]

I guess I need to clarify the question, I is it legal for me to install a 3 Phase handle tie on 120V circuits that share a common Neutral when I can only find the code reference that states they are acceptable on Line to Neutral type Single phase circuits (2Pole)?
Line to neutral IS single phase. The answer is yes. It is a requirement to have handle ties on a MWBC.

[Steve Koszuta]

I guess I need to clarify the question, I is it legal for me to install a 3 Phase handle tie on 120V circuits that share a common Neutral when I can only find the code reference that states they are acceptable on Line to Neutral type Single phase circuits (2Pole)?

DON'T install anything !! If you don't understand that a 120V circuit that shares a common neutral, IS a Line to Neutral single phase load - you are not qualified.

[Richard Robinson]

It would appear that 240.15(B)(1) would appy in the case of our furniture that serves only Line to Neutral loads for office areas. In that case it states only single phase loads can be tied together? Found a pretty good article that discusses the proper use of handle ties on 2 breakers. 240.15(B)(3) discusses 3 Phase but it states line to line with a neutral. I see that as a 5 wire L21-20R with a matching plug or simular load with three phases that require a neutral.Blog - Newsroom - Newsroom - Communications - Independent Electrical Contractors (http://www.ieci.org/newsroom-and-insights/multi-wire-branch-circuits)(1) Multiwire Branch Circuits

Individual single-pole circuit breakers, with identified handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only SINGLE PHASE line-to-neutral loads.Read (B)(1) from above and what 2014 NEC actually states (notice the SINGLE PHASE that was added.

- - - Updated - - -


It would appear that 240.15(B)(1) would appy in the case of our furniture that serves only Line to Neutral loads for office areas. In that case it states only single phase loads can be tied together? Found a pretty good article that discusses the proper use of handle ties on 2 breakers. 240.15(B)(3) discusses 3 Phase but it states line to line with a neutral. I see that as a 5 wire L21-20R with a matching plug or simular load with three phases that require a neutral.Blog - Newsroom - Newsroom - Communications - Independent Electrical Contractors (http://www.ieci.org/newsroom-and-insights/multi-wire-branch-circuits)(1) Multiwire Branch Circuits

Individual single-pole circuit breakers, with identified handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only SINGLE PHASE line-to-neutral loads.Read (B)(1) from above and what 2014 NEC actually states (notice the SINGLE PHASE that was added.

- - - Updated - - -


It would appear that 240.15(B)(1) would appy in the case of our furniture that serves only Line to Neutral loads for office areas. In that case it states only single phase loads can be tied together? Found a pretty good article that discusses the proper use of handle ties on 2 breakers. 240.15(B)(3) discusses 3 Phase but it states line to line with a neutral. I see that as a 5 wire L21-20R with a matching plug or simular load with three phases that require a neutral.Blog - Newsroom - Newsroom - Communications - Independent Electrical Contractors (http://www.ieci.org/newsroom-and-insights/multi-wire-branch-circuits)(1) Multiwire Branch Circuits

Individual single-pole circuit breakers, with identified handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only SINGLE PHASE line-to-neutral loads.Read (B)(1) from above and what 2014 NEC actually states (notice the SINGLE PHASE that was added.

- - - Updated - - -


Handle ties are legal for single phase and 3-phase, each with provisions.

First and foremost is that the handle ties have to be identified (presumably, applying 110.3(B), that means for the breakers they are used on), and they also have to be such that when one breaker trips all the tied-together-with-handle-ties breakers must trip (those old Square D ones which were short aluminum rods with turned down spindle ends typically did not accomplish that).

240.15(B)(1) addresses single-phase multiwire branch circuits with single-pole breakers and which serve only line-to-neutral loads (which is what a multiwire branch circuit does).

240.15(B)(2) addresses single-phase 120/240 volt circuits with single-pole breakers which serve line-to-line single-phase circuits (regular 240 volt circuits).

240.15(B)(3) addresses 3-phase and 2-phase 120/240 volt circuits with single-pole breakers which serve line-to-line circuits as long as there is a grounded neutral point and the voltage does not exceed 120 volts to ground.

240.15(B)(4) addresses 3-wire DC circuits. nut which is not likely to be encountered by home inspectors, except possibly DC PV circuits from PV solar systems.

Anyway, the point is that 3-phase is not a prohibited use - just limited to what is addressed ... as the other uses are.Sorry Look at this (B)(1). I will get a decision from ICC.

[Bill Kriegh]

I think it is important to note here that single breakers with handle ties behave like fuses in a fused disconnect.

In an overload situation only one breaker or fuse may open. Handle ties are designed to allow the limited handle movement of a breaker to allow this to happen. At the same time, the design of the handle tie make it extremely hard to manually turn off a single breaker and so opens all the poles at once - the code requirement for the "disconnect" part of things. Whether or not all the poles opening at the same time is required depends on the application, and if required a common internal trip is required and single breakers with handle ties wouldn't be allowed

A circuit breaker is not functioning as a disconnect when it trips due to an overload, but only when manually operated.

Jerry, we chatted about this one before several years ago and I believe I copied a letter from Eaton/Cuttler Hammer to you similar to the Schneider letter copied here. Essentially, all handle ties do is allow individual breakers to act like a disconnect.

[Ben Jacks]

This might be an easy one but can anyone cite a verse in the NEC that states handle ties are or are not legal when required by 210.4(B)?

Hi RR,
In answer to whether handle ties are or are not legal when required by [210.4(B)] depends on the definition of 'a means' to simultaneously disconnect all ungrounded conductors where the branch circuit or multi-branch circuit originates. The 'means' to disconnect does not necessarily imply that two overcurrent protection device breakers tripped, but defines a manual turn off of the circuit. A tie bar bridging two single pole breaker handles together is 'permitted' at the point of origin where a multi-branch circuit feed to a same yoke or mounting strap to a device or piece of equipment, has as stated in [210.7], been disconnected.
This is a requirement for safety that experienced electricians are schooled for to make sure when working in an outlet, that when the associated problem circuit is shut off at the source, and whether or not it has a split phase (LINE to LINE)...that the manual turn-off forces both breakers off even if only one single pole has been originally tripped. Basically [210.7] requires "a means" as a handle tie requirement or common single handle of a 2 pole configuration. Note that [240.8] restricts fuses, circuit breakers or combinations that shall not be otherwise connected in parallel (by another 'means') if they are not factory assembled.

[Jerry Peck]

I think it is important to note here that single breakers with handle ties behave like fuses in a fused disconnect.

In an overload situation only one breaker or fuse may open.

Correct.


Handle ties are designed to allow the limited handle movement of a breaker to allow this to happen.

Most handle ties that I recall seeing in the tripped off position (which has not been very often as I do not do service work where a breaker would be tripped off) shuts off the one breaker when the other breaker trips off (because the handle ties are tight-fitting on the breaker handles).

The main exception where those old Square D ones I described, and with those, one could turn off (disconnect) one breaker without turning off (disconnecting) both breakers - I saw that a number of times. Thus the handle ties did not fulfill their needed operation of "disconnecting" all ungrounded conductors at the same time.


At the same time, the design of the handle tie make it extremely hard to manually turn off a single breaker and so opens all the poles at once - the code requirement for the "disconnect" part of things.

A circuit breaker is not functioning as a disconnect when it trips due to an overload, but only when manually operated.

Jerry, we chatted about this one before several years ago and I believe I copied a letter from Eaton/Cuttler Hammer to you similar to the Schneider letter copied here. Essentially, all handle ties do is allow individual breakers to act like a disconnect.

Yes, and was discussed as above and still holds true.

[Jerry Peck]

Note that [240.8] restricts fuses, circuit breakers or combinations that shall not be otherwise connected in parallel (by another 'means') if they are not factory assembled.

Correct, and "in parallel" does not mean two single-pole breakers protecting a 240 volt circuit or a MWBC - two single pole breakers (or fuses) in parallel means that both are in parallel protecting one conductor, giving two paths for the same current to go.

[Richard Robinson]

Hi RR,
In answer to whether handle ties are or are not legal when required by [210.4(B)] depends on the definition of 'a means' to simultaneously disconnect all ungrounded conductors where the branch circuit or multi-branch circuit originates. The 'means' to disconnect does not necessarily imply that two overcurrent protection device breakers tripped, but defines a manual turn off of the circuit. A tie bar bridging two single pole breaker handles together is 'permitted' at the point of origin where a multi-branch circuit feed to a same yoke or mounting strap to a device or piece of equipment, has as stated in [210.7], been disconnected.
This is a requirement for safety that experienced electricians are schooled for to make sure when working in an outlet, that when the associated problem circuit is shut off at the source, and whether or not it has a split phase (LINE to LINE)...that the manual turn-off forces both breakers off even if only one single pole has been originally tripped. Basically [210.7] requires "a means" as a handle tie requirement or common single handle of a 2 pole configuration. Note that [240.8] restricts fuses, circuit breakers or combinations that shall not be otherwise connected in parallel (by another 'means') if they are not factory assembled. This question has come up because all the furnitue at our facilities came manufactured with three phases sharing a neutral. I am suggesting they start tieing breakers together when they reconfigure the cubicles but two breakers is all I can see that NEC states is legal to use handle ties on. Is that correct?

[Jerry Peck]

This question has come up because all the furnitue at our facilities came manufactured with three phases sharing a neutral.

What is the actual voltage/phase rating on the nameplate label? You will - should - find a nameplate label on each piece which gives the ratings.

Just checking to make sure it is 3-phase and not intended for 120 volt MWBC.

[Richard Robinson]

What is the actual voltage/phase rating on the nameplate label? You will - should - find a nameplate label on each piece which gives the ratings.

Just checking to make sure it is 3-phase and not intended for 120 volt MWBC.It is 120V Multi Wire and only serves 120V 15Amp plugs. The plus have A B an C Labels to indicate Phase and are snapped onto the fruniture raceway. They all share on Neutral and were originally installed on single pole breakers. I am trying to enforce the handle ties being added when cubes are rearranged but I read only single phase (2-Pole) handle tie are allowed for this application.wr

[Ben Jacks]

Correct, and "in parallel" does not mean two single-pole breakers protecting a 240 volt circuit or a MWBC - two single pole breakers (or fuses) in parallel means that both are in parallel protecting one conductor, giving two paths for the same current to go.

Hi Jerry,
The NEC [240.8] is referring to manufactured two breaker disconnects assembled together as a unit at the factory. Could you give an Article/Section reference for the conductor dual protection using two different OCPD's defining the same current path mentioned? I am not sure where that is in the NEC and could use help. Thanks.

[Ben Jacks]

This question has come up because all the furnitue at our facilities came manufactured with three phases sharing a neutral. I am suggesting they start tieing breakers together when they reconfigure the cubicles but two breakers is all I can see that NEC states is legal to use handle ties on. Is that correct?

RR,
I am following that each cubicle has three 120V, 1ph circuits, sharing a possible overloaded single neutral and also creating the handle ties problem. If that is the case, then you can remove one ungrounded conductor, and have a 2 pole breaker disconnecting the other two split phase branch circuits to be compliant with [210.7]. Can each cubicle hold a two 20A circuit Demand with this single phase supplied commercial building? I would calc out the required group loads first.

[Ben Jacks]

It is 120V Multi Wire and only serves 120V 15Amp plugs. The plus have A B an C Labels to indicate Phase and are snapped onto the fruniture raceway. They all share on Neutral and were originally installed on single pole breakers. I am trying to enforce the handle ties being added when cubes are rearranged but I read only single phase (2-Pole) handle tie are allowed for this application.wr

RR,
I notice you mention 15A Plugs (AKA receptacles?) but if this is a commercial office, then 20A #12 AWG conductor wiring is required. If this is really #14 AWG 15A wiring...then an upgrade is in order.

[Jerry Peck]

Correct, and "in parallel" does not mean two single-pole breakers protecting a 240 volt circuit or a MWBC - two single pole breakers (or fuses) in parallel means that both are in parallel protecting one conductor, giving two paths for the same current to go.


Hi Jerry,
The NEC [240.8] is referring to manufactured two breaker disconnects assembled together as a unit at the factory. Could you give an Article/Section reference for the conductor dual protection using two different OCPD's defining the same current path mentioned? I am not sure where that is in the NEC and could use help. Thanks.

Ben,

The photo is showing what I am describing: 4 single pole breakers assembled into one unit which is protecting 2 conductors ... i.e., 2 of those single pole breakers are in parallel and are protecting one conductor, and the other 2 of those single pole breakers are also in parallel and are also protecting one conductor - with the 4 single pole breakers assembled into one unit protecting 2 conductors.

[Brad Richter]

RR,
I notice you mention 15A Plugs (AKA receptacles?) but if this is a commercial office, then 20A #12 AWG conductor wiring is required. If this is really #14 AWG 15A wiring...then an upgrade is in order.
Where would one find this requirement?

Additonally, 15 amp receps are allowed on 20 amp 12 guage circuits. The OP has not given any indication of circuit ampacity, only ampacity of the receps.

[Jim Port]

RR,
I notice you mention 15A Plugs (AKA receptacles?) but if this is a commercial office, then 20A #12 AWG conductor wiring is required. If this is really #14 AWG 15A wiring...then an upgrade is in order.

While this is a common commercial job spec it is not part of the NEC.

[Jim Port]

RR,
I am following that each cubicle has three 120V, 1ph circuits, sharing a possible overloaded single neutral and also creating the handle ties problem. If that is the case, then you can remove one ungrounded conductor, and have a 2 pole breaker disconnecting the other two split phase branch circuits to be compliant with [210.7]. Can each cubicle hold a two 20A circuit Demand with this single phase supplied commercial building? I would calc out the required group loads first.

The OP stated the hots were labeled A, B and C. They can share a single neutral without overloading it. Remember this is a three phase building, not single phase where two of those legs would be on the same hot.

[Ben Jacks]

Ben,

The photo is showing what I am describing: 4 single pole breakers assembled into one unit which is protecting 2 conductors ... i.e., 2 of those single pole breakers are in parallel and are protecting one conductor, and the other 2 of those single pole breakers are also in parallel and are also protecting one conductor - with the 4 single pole breakers assembled into one unit protecting 2 conductors.
Jerry,
OK you win. If those conductors are used for the parallel branch circuits in this application, then that would comply with the [310.10(H)] larger conductors requirements...but, realistically, smaller size #12 or #14 paralleled wires are not permitted when used in the intent related to the [240.8] breaker and handle requirements being discussed. Thanks for the pic.

[Ben Jacks]

The OP stated the hots were labeled A, B and C. They can share a single neutral without overloading it. Remember this is a three phase building, not single phase where two of those legs would be on the same hot.

Hi Jim,
I must have missed the part where a 3 phase service/panelboard was mentioned...that is why I asked about the reason why or if this was a single phase facility with a 3ph A,B,C labeled cubicle strip distribution setup. So if the panelboard feed has a 3ph potential, why hasn't someone mentioned upgrading the supply feeders and OCPD's? Just asking.

[Ben Jacks]

While this is a common commercial job spec it is not part of the NEC.

Maybe this facility was wired without a commercial permit and project design requirement, who knows other than the AHJ. If the OP is an inspector, he should know to ask what the local codes were at the time of construction. Rarely is a commercial job wired using a 14 AWG permitted requirement. I know from experience from wiring facilities since 1956 that is just not the case in most contracts unless you are doing dwelling/commercial projects.

Jim, you and I both know where AWG size wiring is part of the NEC to demonstrate what the project Demand Factors are to dictate economical wiring practices to code and to be competitive to make a profit on contracts to stay in business.

- - - Updated - - -


While this is a common commercial job spec it is not part of the NEC.

Maybe this facility was wired without a commercial permit and project design requirement, who knows other than the AHJ. If the OP is an inspector, he should know to ask what the local codes were at the time of construction. Rarely is a commercial job wired using a 14 AWG permitted requirement. I know from experience from wiring facilities since 1956 that is just not the case in most contracts unless you are doing dwelling/commercial projects.

Jim, you and I both know where AWG size wiring is part of the NEC to demonstrate what the project Demand Factors are to dictate economical wiring practices to code and to be competitive to make a profit on contracts to stay in business.

[Ben Jacks]

Where would one find this requirement?

Additonally, 15 amp receps are allowed on 20 amp 12 guage circuits. The OP has not given any indication of circuit ampacity, only ampacity of the receps.

Hi Brad,
Evidently, the context of what I replied about was not apparent. Sorry you had to repeat what I said.

[Jerry Peck]

If those conductors are used for the parallel branch circuits ...

Ben,

We're not referring to parallel conductors, the topic was for overcurrent protection breakers, and then drifted into parallel breakers.

That photo is of a service disconnect, the conductors are the service entrance conductors. It is just a good photo showing parallel breakers (4) protecting conductors (2).

[Richard Robinson]

Maybe this facility was wired without a commercial permit and project design requirement, who knows other than the AHJ. If the OP is an inspector, he should know to ask what the local codes were at the time of construction. Rarely is a commercial job wired using a 14 AWG permitted requirement. I know from experience from wiring facilities since 1956 that is just not the case in most contracts unless you are doing dwelling/commercial projects.

Jim, you and I both know where AWG size wiring is part of the NEC to demonstrate what the project Demand Factors are to dictate economical wiring practices to code and to be competitive to make a profit on contracts to stay in business.

- - - Updated - - -



Maybe this facility was wired without a commercial permit and project design requirement, who knows other than the AHJ. If the OP is an inspector, he should know to ask what the local codes were at the time of construction. Rarely is a commercial job wired using a 14 AWG permitted requirement. I know from experience from wiring facilities since 1956 that is just not the case in most contracts unless you are doing dwelling/commercial projects.

Jim, you and I both know where AWG size wiring is part of the NEC to demonstrate what the project Demand Factors are to dictate economical wiring practices to code and to be competitive to make a profit on contracts to stay in business.The facility was inspected and there are literaly thousands of cubicles. The wire size is #10 and they are protected by 20 Amp Single pole breakers. The furniture whips are manufactured with three phases that share one neutral and that is the way the wire are pullled back to the three phase panels. There is always remodeling going on and I am trying to make them go ahead and tie the breakers that share neutrals together when modification occur but cannot prove the three phase handle ties are legal for this application.

[Ben Jacks]

Ben,

We're not referring to parallel conductors, the topic was for overcurrent protection breakers, and then drifted into parallel breakers.

That photo is of a service disconnect, the conductors are the service entrance conductors. It is just a good photo showing parallel breakers (4) protecting conductors (2).

Jerry,
If we are discussing the thread topic about individual branch circuit distribution to cubicles, then I do not think parallel service entrance conductors/mains you have shown in the photo is relevant. The NEC[310.10(H)] does not permit a small size conductor under 1/0 AWG to be in an end-to-end parallel configuration for a common path circuit that you described earlier from two breakers.
OCPD breakers must be manufactured at the factory assembled together to be compliant with [240.8] as in the case of the 2 pair of tie-bar ganged breakers shown in your pic.

If the facility is a 1ph system, the concern is then about a shared neutral in a 3ph wiring configuration that might eventually become overloaded under certain simultaneous 3 ungrounded wire circuit usage. So what would be your solution for the OP as a resolution of 3ph wiring cublicle strips sharing a 1ph single neutral in the same enclosure?

[Jerry Peck]

Jerry,
If we are discussing the thread topic about individual branch circuit distribution to cubicles, then I do not think parallel service entrance conductors/mains you have shown in the photo is relevant.

Ben,

Parallel BREAKERS are relevant as that is where the thread drift went - I responded to YOUR comment regarding parallel BREAKERS ... therefore my comment and photo is relevant as it shows, and addresses, parallel BREAKERS ... whether those parallel BREAKERS are for branch circuit protection of mains service disconnect does not affect the location of those parallel BREAKERS.

Thank YOU for bringing up the parallel BREAKERS drift to this thread, but, now ... :focus:

[Ben Jacks]

The facility was inspected and there are literaly thousands of cubicles. The wire size is #10 and they are protected by 20 Amp Single pole breakers. The furniture whips are manufactured with three phases that share one neutral and that is the way the wire are pullled back to the three phase panels. There is always remodeling going on and I am trying to make them go ahead and tie the breakers that share neutrals together when modification occur but cannot prove the three phase handle ties are legal for this application.

RR,
Thanks for a better description that defines the actual problem. Now Jim can relax about my comments on 12AWG wiring for the 20A circuits that we now know are using 10AWG neutrals in a 3ph distribution from single pole breakers. So emphasis on a 2pole tie-bar does in fact cause concern for a distribution that should be using a 3pole disconnect for a like circuit group ...and unfortunately a changeout seems to be the answer to meet [210.7] outlet requirements. The good news is if the other two BC legs are run as pass-throughs in each outlet (without connector junctions), then [210.7] goes away at a whip interface!!! My apologies for the bad humor.

[Brad Richter]

RR,
Thanks for a better description that defines the actual problem. Now Jim can relax about my comments on 12AWG wiring for the 20A circuits that we now know are using 10AWG neutrals in a 3ph distribution from single pole breakers. So emphasis on a 2pole tie-bar does in fact cause concern for a distribution that should be using a 3pole disconnect for a like circuit group ...and unfortunately a changeout seems to be the answer to meet [210.7] outlet requirements. The good news is if the other two BC legs are run as pass-throughs in each outlet (without connector junctions), then [210.7] goes away at a whip interface!!! My apologies for the bad humor.

210.4(A) and 210.4(B) are the applicable references not 210.7. "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". Which in turn references 240.15(B)(1). "Individual single-pole circuit breakers with identified handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only single-phase line-to-neutral loads".

[Jerry Peck]

Question for clarification from the electricians:
- A 3-phase service is supplying a condo building, the building is divided up and on the different phases so each stack of condo units is fed with 120 volt/308 volt.
- Do you refer to that as single-phase or 3-phase?

(Yes, as you likely suspect, I have a reason for asking.)

[Brad Richter]

Question for clarification from the electricians:
- A 3-phase service is supplying a condo building, the building is divided up and on the different phases so each stack of condo units is fed with 120 volt/308 volt.
- Do you refer to that as single-phase or 3-phase?

(Yes, as you likely suspect, I have a reason for asking.)
I think you mean 120/208 volts.
Two phases of a 120/208 wye system to a utilization equipment is single phase.

[Ben Jacks]

210.4(A) and 210.4(B) are the applicable references not 210.7. "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". Which in turn references 240.15(B)(1). "Individual single-pole circuit breakers with identified handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only single-phase line-to-neutral loads".

Well it all depends whether you look at both ends of distribution of the branch circuit requirements such as from a supply side [210.4] vs. the load outlet side of what is dictated. [210.7] describes the equipment side a lot quicker when working on the outlet for multiwire edicts of supplying a load or device requirement from a safety disconnect perspective. I hope this helps.

[Jerry Peck]

I think you mean 120/208 volts.

That is correct, 308 was a typos, 208 is what I meant.


Two phases of a 120/208 wye system to a utilization equipment is single phase.

And phases A, B, C to the utilization equipment would be 3-phase?

[Brad Richter]

That is correct, 308 was a typos, 208 is what I meant.



And phases A, B, C to the utilization equipment would be 3-phase?
That is correct.

[Jerry Peck]

That is correct, 308 was a typos, 208 is what I meant.



And phases A, B, C to the utilization equipment would be 3-phase?


That is correct.

And as I recall, he said his wired for connection to A, B, & C ... making his stuff 3-phase.

[Brad Richter]

And as I recall, he said his wired for connection to A, B, & C ... making his stuff 3-phase.
His equipment is wired line to neutral. That is single phase. 3 phase equipment uses three ungrounded conductors, not three ungrounded conductors and a grounded conductor.

[Jerry Peck]

His equipment is wired line to neutral. That is single phase. 3 phase equipment uses three ungrounded conductors, not three ungrounded conductors and a grounded conductor.

I went back and reviewed the posts, and, there it was in post 6 where he said line to neutral.

I missed that part and have been playing catch-up since, I didn't do 3-phase wiring back so many years ago, and I have not inspected much 3-phase over the years, I got sidetracked in trying to follow what was being said because it did not compute ... and there it was in post 6.

[Brad Richter]

I went back and reviewed the posts, and, there it was in post 6 where he said line to neutral.

I missed that part and have been playing catch-up since, I didn't do 3-phase wiring back so many years ago, and I have not inspected much 3-phase over the years, I got sidetracked in trying to follow what was being said because it did not compute ... and there it was in post 6.

I, for one, have never mis-read a post........NOT!

[Richard Robinson]

210.4(A) and 210.4(B) are the applicable references not 210.7. "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". Which in turn references 240.15(B)(1). "Individual single-pole circuit breakers with identified handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only single-phase line-to-neutral loads".
So I can enforce using a 3-Pole handle tie to comply with the intent of NEC requirement that all ungrounded conductors open simultaneously when they share a neutral? The fact that single phase shows up at the end of 240.15(B)(1) makes me concerned about making it a 3-Phase circiut breaker.

rr

[Brad Richter]

So I can enforce using a 3-Pole handle tie to comply with the intent of NEC requirement that all ungrounded conductors open simultaneously when they share a neutral. The fact that single phase shows up at the end of 240.15(B)(!) makes me concerned about making it a 3-Phase circiut breaker.

rr
Maybe someone will come along to better explain it to your satisfaction. I don't know what else I can post to ease your mind.

[Jerry Peck]

So I can enforce using a 3-Pole handle tie to comply with the intent of NEC requirement that all ungrounded conductors open simultaneously when they share a neutral. The fact that single phase shows up at the end of 240.15(B)(!) makes me concerned about making it a 3-Phase circiut breaker.

rr

It's a three circuit breaker, but (now that I am on the same page) each circuit is on a single phase.

Additionally, I'm not sure that anything in the NEC prohibits using handle ties on other breakers, as long as the handle tie is an identified handle tie for the breakers it is being installed on.

I.e, nothing I can think of prohibits a double pole internal trip breaker from serving two single phase circuits, or prohibits two single pole breakers from serving two single phase circuits, which would indicate that installing a handle tie for a 3 pole or 4 pole breaker on three or four single pole breaker would not be prohibited either - I guess we shall find out about that soon enough ... :)

[Richard Robinson]

It's a three circuit breaker, but (now that I am on the same page) each circuit is on a single phase.

Additionally, I'm not sure that anything in the NEC prohibits using handle ties on other breakers, as long as the handle tie is an identified handle tie for the breakers it is being installed on.

I.e, nothing I can think of prohibits a double pole internal trip breaker from serving two single phase circuits, or prohibits two single pole breakers from serving two single phase circuits, which would indicate that installing a handle tie for a 3 pole or 4 pole breaker on three or four single pole breaker would not be prohibited either - I guess we shall find out about that soon enough ... :)There is another reason for my concern, our plant does very high quality work and has never allowed the use of handle ties so I have to be sure introduciing the use of them is done correctly. Did you see this:Blog - Newsroom - Newsroom - Communications - Independent Electrical Contractors (http://www.ieci.org/newsroom-and-insights/multi-wire-branch-circuits)

[Richard Robinson]

There is another reason for my concern, our plant does very high quality work and has never allowed the use of handle ties so I have to be sure introduciing the use of them is done correctly. Did you see this:Blog - Newsroom - Newsroom - Communications - Independent Electrical Contractors (http://www.ieci.org/newsroom-and-insights/multi-wire-branch-circuits)I like the way you described it and will have to quote you. It is becoming a three circuit breaker and not a three phase breaker. "Individual single-pole circuit breakers with identified handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only single-phase line-to-neutral loads"

[Jerry Peck]

I like the way you described it and will have to quote you. It is a three circuit breaker and not a three phase breaker.

It is a 3-phase breaker in that it is fed from the 3-phase supply and it disconnects all loads from that 3-phase supply. One could use an internal trip three-pole breaker for 3-phase breaker in place of the 3 single pole breakers.

However, that 3 circuit breaker does not have a 3-phase load attached to its load terminals, it has three single phase line to neutral loads.

Thus, while it seems like splitting hairs to call it a 3 circuit breaker instead of a 3-phase breaker (maybe it is splitting hairs, but it is also accurately describing the circuits and their loads - I am still waiting for input from the electricians), I would not say that it is not a 3-phase breaker (as it is disconnecting the circuits from the 3-phase supply), I would just say it is for 3 circuits (which is how the three single pole breakers have been used in the past).

Kind of like having a 120 volt/240 volt circuit supplying a range where 120 volts is used for the oven light and the electronics (line to neutral load) and the 240 volts is used for the heating elements (line to line load), versus, a 120 volt/240 volt circuit which supplies two line to neutral loads and no line to line load (i.e., a multiwire-branch circuit). The same type of double pole breaker used for the range circuit can also be used for the MWBC - it's the circuits and their loads which define what it is.

Okay, we'll now let the electricians sort that out ... :)

[Richard Robinson]

It is a 3-phase breaker in that it is fed from the 3-phase supply and it disconnects all loads from that 3-phase supply. One could use an internal trip three-pole breaker for 3-phase breaker in place of the 3 single pole breakers.

However, that 3 circuit breaker does not have a 3-phase load attached to its load terminals, it has three single phase line to neutral loads.

Thus, while it seems like splitting hairs to call it a 3 circuit breaker instead of a 3-phase breaker (maybe it is splitting hairs, but it is also accurately describing the circuits and their loads - I am still waiting for input from the electricians), I would not say that it is not a 3-phase breaker (as it is disconnecting the circuits from the 3-phase supply), I would just say it is for 3 circuits (which is how the three single pole breakers have been used in the past).

Kind of like having a 120 volt/240 volt circuit supplying a range where 120 volts is used for the oven light and the electronics (line to neutral load) and the 240 volts is used for the heating elements (line to line load), versus, a 120 volt/240 volt circuit which supplies two line to neutral loads and no line to line load (i.e., a multiwire-branch circuit). The same type of double pole breaker used for the range circuit can also be used for the MWBC - it's the circuits and their loads which define what it is.

Okay, we'll now let the electricians sort that out ... :)We are finally getting to the meat of my original question.

- - - Updated - - -


I like the way you described it and will have to quote you. It is becoming a three circuit breaker and not a three phase breaker. "Individual single-pole circuit breakers with identified handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only single-phase line-to-neutral loads"Edited

[Jerry Peck]

WARNING! THREAD DRIFT! :)

while we are on breakers and their ratings, I doubt many electricians or inspectors look for this, and it is beyond the scope for home inspectors (and would typically only be found in the condo building I described which is supplied by a 3-phase service yet each stack of condo units is only supplied with 120 volt/208 volt.

From the UL breaker marking guide.
"Based on the preceding paragraphs, “slant-rated” breakers (120/240, 208Y/120 V, etc., as opposed to 240, 480 V, etc.) are not intended for use on “slant-rated” delta systems. For example, a 3-pole, 120/240 V breaker is not intended for use on a 240/120 V, 3-phase, 4-wire, delta system, because on the high leg, the voltage to neutral is 208 V. In this instance, a 3-pole, 240 V breaker should be used."

I wonder how many 120 volt/240 volt rated breakers are installed on 120 volt/208 volt systems? Should not be any.

[Richard Robinson]

Becoming a little frustrated with this new find (Inspectornews.net). Thought it was a good find but have been called less than professional and this thread has strayed. How many "Electricians" here have even attempted the International Code Council E2 Commercial Inspector test? I have a Master and an E3 Certification, guess ICC does not know how to qualify.

[Jim Port]

This site is mainly for home and commercial inspectors, not code inspectors.

I don't specifically know what you are talking about conductwise, but the same debates happens on sites like Mike Holts amongst trade professionals.

[Richard Robinson]

WARNING! THREAD DRIFT! :)

while we are on breakers and their ratings, I doubt many electricians or inspectors look for this, and it is beyond the scope for home inspectors (and would typically only be found in the condo building I described which is supplied by a 3-phase service yet each stack of condo units is only supplied with 120 volt/208 volt.

From the UL breaker marking guide.
"Based on the preceding paragraphs, “slant-rated” breakers (120/240, 208Y/120 V, etc., as opposed to 240, 480 V, etc.) are not intended for use on “slant-rated” delta systems. For example, a 3-pole, 120/240 V breaker is not intended for use on a 240/120 V, 3-phase, 4-wire, delta system, because on the high leg, the voltage to neutral is 208 V. In this instance, a 3-pole, 240 V breaker should be used."

I wonder how many 120 volt/240 volt rated breakers are installed on 120 volt/208 volt systems? Should not be any.I have been doing electrical work for an eternity it seems and have never seen a Delta system where the midpoint of one phase is grounded creating a "high" leg. Have seen a ungrounded Delta on a tower crane where a short to ground did not effect the operation of the crane but when trouble shooting, 480 Volts to ground readings on two phases and 0 Volts to ground on the third leg freaked me out initially.

[Jerry Peck]

I have been doing electrical work for an eternity it seems and have never seen a Delta system where the midpoint of one phase is grounded creating a "high" leg. Have seen a ungrounded Delta on a tower crane where a short to ground did not effect the operation of the crane but when trouble shooting, 480 Volts to ground readings on two phases and 0 Volts to ground on the third leg freaked me out initially.

I'm not saying 'how often' the various systems are used or 'how often' any particular person will see the various systems, just that the systems are there and used in applicable installations.

Go here:
- Using Single-Phase Transformers to Create 3-Phase Systems | Basics content from Electrical Construction & Maintenance (EC&M) Magazine (http://ecmweb.com/basics/using-single-phase-transformers-create-3-phase-systems) ,
- then click on "Fig. 2 (click here to see Fig. 2) (http://ecmweb.com/images/904ewBTBfig2.jpg). ",
- - and you will see this: http://ecmweb.com/site-files/ecmweb.com/files/archive/ecmweb.com/images/904ewBTBfig2.jpg

[Bill Kriegh]

I guess I need to clarify the question, I is it legal for me to install a 3 Phase handle tie on 120V circuits that share a common Neutral when I can only find the code reference that states they are acceptable on Line to Neutral type Single phase circuits (2Pole)?

NO. 240.15(B)(1) says single phase line to neutral loads only.

And, to clarify, three different 3 phase hot legs that share a neutral, a multi wire circuit, is a single circuit. This means that in answer to Jerry's question the load is actually a 3 phase load. Why, because line to neutral loads will divide the loads between the 3 lines and the neutral will wind up carrying only the difference. (in theory - with pure resistive loads. In actuality harmonics from switching power supplies and other "stuff" need to be taken into account when sizing neutrals on multi wire circuits)

[Brad Richter]

NO. 240.15(B)(1) says single phase line to neutral loads only.

And, to clarify, three different 3 phase hot legs that share a neutral, a multi wire circuit, is a single circuit. This means that in answer to Jerry's question the load is actually a 3 phase load. Why, because line to neutral loads will divide the loads between the 3 lines and the neutral will wind up carrying only the difference. (in theory - with pure resistive loads. In actuality harmonics from switching power supplies and other "stuff" need to be taken into account when sizing neutrals on multi wire circuits)
Sorry, that is totally incorrect.

[Bill Kriegh]

Sorry, that is totally incorrect.

OK. Dig out your Amprobe and prove me wrong.

[Brad Richter]

OK. Dig out your Amprobe and prove me wrong.
Just what would that prove?

[Bill Kriegh]

I said that in a 3 phase multi wire circuit where all the loads are resistive and the same that the lines would divide up the loads, a 3 phase load.

If you change one of the loads the neutral carries the difference, but you still have a 3 phase load for the balanced part of the load.

You said that's wrong. Prove it

[Brad Richter]

I said that in a 3 phase multi wire circuit where all the loads are resistive and the same that the lines would divide up the loads, a 3 phase load.

If you change one of the loads the neutral carries the difference, but you still have a 3 phase load for the balanced part of the load.

You said that's wrong. Prove it
That part is correct. The notion that handle ties should not be used is incorrect. It is a mwbc so a 3 pole breaker or three single pole breakers with ties is necessary.

[Jerry Peck]

Question for clarification from the electricians:
- A 3-phase service is supplying a condo building, the building is divided up and on the different phases so each stack of condo units is fed with 120 volt/308 volt.
- Do you refer to that as single-phase or 3-phase?

(Yes, as you likely suspect, I have a reason for asking.)


I think you mean 120/208 volts.
Two phases of a 120/208 wye system to a utilization equipment is single phase.

Yes, I did mean 208 volts, the 308 was a typo.


NO. 240.15(B)(1) says single phase line to neutral loads only.

And, to clarify, three different 3 phase hot legs that share a neutral, a multi wire circuit, is a single circuit. This means that in answer to Jerry's question the load is actually a 3 phase load. Why, because line to neutral loads will divide the loads between the 3 lines and the neutral will wind up carrying only the difference. (in theory - with pure resistive loads. In actuality harmonics from switching power supplies and other "stuff" need to be taken into account when sizing neutrals on multi wire circuits)

Bill, that means the service to the building is 3-phase and that the supply to each stack of condos in my example is also 3-phase, or that the service to the building is 3-phase and the supply to each stack is single phase?