Two loads on a single breaker (not the normal landing two wires on a breaker)

[sfav8r]

We have a situation where there is a 3,000A main panel. All available slots are being used to feed sub panels and chillers. One of the chillers is a 200a unit. The breaker feeding that chiller has three lugs on it. We landed another load on that breaker using one of the two available lugs. The inspector said that we cannot land two wires on a breaker. We discussed the fact that there was clearly 3 separate lugs on the breaker for the purpose of landing wires there. The inspector felt that those were only for parallel wires to the same load and said that the NEC does not allow a single breaker to supply two separate loads like we did. I cannot find any such limitation. Most circuit breakers feed multiple loads (receptacles etc.) so I'm not sure exactly what he meant. Can someone give me a code section that addresses this?

Thanks.

 

[iwire]

IMO the inspector is mistaken if he is shooting it down for the reasons you state.

However if I was the inspector I would have a lot of question about the minimum and maximum circuit requirements of the two units involved.

It seems pretty doubtful that breaker is correctly sized for both loads and conductors.

 

[petersonra]

As long as the tap rules are followed you should be OK, if all the other rules are followed.

 

[iwire]

As long as the tap rules are followed you should be OK.

Can you give an example?

 

[petersonra]

Can you give an example?

I was editing while you were replying. I could see it being OK if the current requirement of the new device is relatively low.

 

[Smart $]

Can you give an example?

The 200A chiller is fed with a 300A breaker and conductors, then has a local 200A-fused disconnect.

New load fed with 150A conductors and local 150A fused disconnect off the same 300A breaker.

Tap rules apply to the new load conductors.

 

[iwire]

The 200A chiller is fed with a 300A breaker and conductors, then has a local 200A-fused disconnect.

New load fed with 150A conductors and local 150A fused disconnect off the same 300A breaker.

Tap rules apply to the new load conductors.

Sure tap rules can be easily satisfied. I know that, Bob P knows that, you know that.

But that still leaves the issue of the breaker size. Chillers will have a min and max OCPD size on them.

Are you suggesting a 200 amp chiller would have been installed with a large enough breaker to supply additional loads?

And if the additional load is small enough to fit in that narrow window the breaker will likely be to big for it.

Keep in mind the OP did not mention changing the original breaker size or adding additional OCPDs.

 

[Ragin Cajun]

Does the OP have the chiller NP data?

RC

 

[Smart $]

Sure tap rules can be easily satisfied. I know that, Bob P knows that, you know that.

But that still leaves the issue of the breaker size. Chillers will have a min and max OCPD size on them.

Are you suggesting a 200 amp chiller would have been installed with a large enough breaker to supply additional loads?

And if the additional load is small enough to fit in that narrow window the breaker will likely be to big for it.

Keep in mind the OP did not mention changing the original breaker size or adding additional OCPDs.

I agree there are likely additional issues that must be (or may already have been) addressed.

From our end, need mo' info'.... namely load data, ocpd rating(s), conductor data, perhaps distances for tap rule compliance, yada-yada....

 

[petersonra]

I think we all agree the inspector is just wrong if the OP accurately stated his objections.

But I think we can also agree that there are likely ways this could be code compliant.

For instance, suppose the chiller only requires a 200A circuit and has a downstream fused disconnect with 200A fuses, but the CB is a 300A unit? The OP never said the Cb was 200A, only that the chiller was.

Not enough information to make a call on this one IMO.

 

[kwired]

Maybe the existing load on that breaker is supplied by feeder taps? How many 200 amp breakers have connections for 3 conductors? I can't recall ever seeing a 200 amp breaker that could take anything but one conductor. 3 conductors usually doesn't appear until you get into the 800 amp frame sizes.

I do disagree with the inspector on stating that multiple lugs are for parallel conductors only. Should this be an 800 amp breaker with three lugs per pole, there would be nothing wrong with one, two or three feeder taps being supplied from it.

 

[Pharon]

How many 200 amp breakers have connections for 3 conductors? I can't recall ever seeing a 200 amp breaker that could take anything but one conductor. 3 conductors usually doesn't appear until you get into the 800 amp frame sizes.

I think he said 3 phase conductors, 2 lugs per phase.

 

[kwired]

I think he said 3 phase conductors, 2 lugs per phase.

Maybe, after reading it again I still don't know what he has.

 

[Cavie]

We have a situation where there is a 3,000A main panel. All available slots are being used to feed sub panels and chillers. One of the chillers is a 200a unit. The breaker feeding that chiller has three lugs on it. We landed another load on that breaker using one of the two available lugs. The inspector said that we cannot land two wires on a breaker. We discussed the fact that there was clearly 3 separate lugs on the breaker for the purpose of landing wires there. The inspector felt that those were only for parallel wires to the same load and said that the NEC does not allow a single breaker to supply two separate loads like we did. I cannot find any such limitation. Most circuit breakers feed multiple loads (receptacles etc.) so I'm not sure exactly what he meant. Can someone give me a code section that addresses this?

Thanks.

Ask the inspector to explain SQ D QO with two wire slots per screw.