Emergency panelboard main LSIG

[hhsting]

I understand I had similar post perviously but that post involve GFPE of main service switchboard.

See attached sketch. I have high rise in which their is main service switchboard, emergency gen, ATSs one emergency life and safety and another standby. Switchboard 250A feeder breaker feeds ATS emergency branch. Generfator has 250A main breaker feeding ATS emergency

Emergency ATS feeds emergency panelboard 250A main breaker with LSIG.

Its confusing in this case NEC 2017 section 700.6(D) to indicate a ground fault but not have ground fault protection.

Does NEC 2017 section 700.6(D), 700.31 or any another NEC 2017 article allow ground fault protection breaker in emeregency breaker panelboard with 250A main breaker attach sketch or not?

 

[don_resqcapt19]

What is LSIG? No such term in the NEC.

 

[hhsting]

What is LSIG? No such term in the NEC.

Thats for the breaker setting.

L: long time trip
S: short time trip
I: instantaneous trip
G: ground fault trip

 

[d0nut]

Does NEC 2017 section 700.6(D), 700.31 or any another NEC 2017 article allow ground fault protection breaker in emergency breaker panelboard with 250A main breaker attach sketch or not?

No. Nothing requires ground fault protection in the emergency breaker in your system.

700.6(D) Ground Fault. To indicate a ground fault in solidly grounded wye emergency systems of more than 150 volts to ground and circuit-protective devices rated 1000 amperes or more. The sensor for the ground-fault signal devices shall be located at, or ahead of, the main system disconnecting means for the emergency source, and the maximum setting of the signal devices shall be for a ground-fault current of 1200 amperes. Instructions on the course of action to be taken in event of indicated ground fault shall be located at or near the sensor location.

Looking through the requirements, you have a solidly grounded wye emergency system. Your system is more than 150V to ground. You do not have an emergency circuit-protective device rated 1000A or more. The section does not apply to your installation.

If the emergency branch was 1000A or more, then you would have to provide ground fault indication. Your generator only has a 250A emergency branch, therefore ground fault indication is not required. It could still be provided if desired, but it is not required.

 

[hhsting]

No. Nothing requires ground fault protection in the emergency breaker in your system.

700.6(D) Ground Fault. To indicate a ground fault in solidly grounded wye emergency systems of more than 150 volts to ground and circuit-protective devices rated 1000 amperes or more. The sensor for the ground-fault signal devices shall be located at, or ahead of, the main system disconnecting means for the emergency source, and the maximum setting of the signal devices shall be for a ground-fault current of 1200 amperes. Instructions on the course of action to be taken in event of indicated ground fault shall be located at or near the sensor location.

Looking through the requirements, you have a solidly grounded wye emergency system. Your system is more than 150V to ground. You do not have an emergency circuit-protective device rated 1000A or more. The section does not apply to your installation.

If the emergency branch was 1000A or more, then you would have to provide ground fault indication. Your generator only has a 250A emergency branch, therefore ground fault indication is not required. It could still be provided if desired, but it is not required.

Right so whats provided is a ground fault trip with the breaker Not indication for 250A breaker on emergency system.

Is their a section that prevents or say not to place the ground fault trip circuit breaker on the emergency panelboard main or branch circuit?

 

[don_resqcapt19]

Right so whats provided is a ground fault trip with the breaker Not indication for 250A breaker on emergency system.

Is their a section that prevents or say not to place the ground fault trip circuit breaker on the emergency panelboard main or branch circuit?

See 700.31

 

[hhsting]

See 700.31

I dont follow. 700.31 is for GFPE and refers back to 700.6(D).

What I have is ground fault breaker on 250A breaker in emergency panelboard not sure if thats allowed or not?

 

[d0nut]

I believe the only place where GFPE is prohibited is on the load side of an essential electrical system transfer switch (Article 517).

To clarify your system:
1. GFPE is not required on the 250A breaker, but it is also not prohibited.
2. If you want ground fault detection, but do not want the breaker to open, that is permitted by 700.31.
3. If you do not provide an automatic disconnecting means as permitted by 700.31, you must provide indication meeting the requirements of 700.6(D).

In summary, there is nothing prohibiting the 250A generator breaker from having GFPE. There is also nothing requiring it to have GFPE. It is entirely a design decision. I wouldn't have put GFPE on that breaker, but that is my preference only.

 

[don_resqcapt19]

I dont follow. 700.31 is for GFPE and refers back to 700.6(D).

What I have is ground fault breaker on 250A breaker in emergency panelboard not sure if thats allowed or not?

Please read the code language again. It is very clear what it says. Remember to look at the titles of the two sections.

 

[hhsting]

I believe the only place where GFPE is prohibited is on the load side of an essential electrical system transfer switch (Article 517).

To clarify your system:
1. GFPE is not required on the 250A breaker, but it is also not prohibited.
2. If you want ground fault detection, but do not want the breaker to open, that is permitted by 700.31.
3. If you do not provide an automatic disconnecting means as permitted by 700.31, you must provide indication meeting the requirements of 700.6(D).

In summary, there is nothing prohibiting the 250A generator breaker from having GFPE. There is also nothing requiring it to have GFPE. It is entirely a design decision. I wouldn't have put GFPE on that breaker, but that is my preference only.

Right but LSIG the G part on breaker is it usually ground fault protection of equipment or its Not and something else? Manufacturer just says G is for ground fault????

 

[d0nut]

The G in LSIG is typically for a GFPE trip. Usually when the breaker does not have the trip but only an alarm it will be denoted as LSIA or something similar.

 

[hhsting]

Please read the code language again. It is very clear what it says. Remember to look at the titles of the two sections.

Ok i read both sections.

NEC 2017 section 700.31 says Ground fault protection of equipment. The alternate source for emergency systems shall not be required to provide ground fault protection of equipment with automatic disconnecting means. Ground fault protection at the emergency source shall be provided in accordance with 700.6(D) if ground fault protection of equipment with automatic disconnecting means is not provided.

First above code is about Source for emergency system Not the downstream panelboard. I see source as like the generator. I dont know how this code section applies to post#1 question which has G ground fault dowmstream of source emergency panelboard?
Please anyone help as well

 

[hhsting]

I believe the only place where GFPE is prohibited is on the load side of an essential electrical system transfer switch (Article 517).

To clarify your system:
1. GFPE is not required on the 250A breaker, but it is also not prohibited.
2. If you want ground fault detection, but do not want the breaker to open, that is permitted by 700.31.
3. If you do not provide an automatic disconnecting means as permitted by 700.31, you must provide indication meeting the requirements of 700.6(D).

In summary, there is nothing prohibiting the 250A generator breaker from having GFPE. There is also nothing requiring it to have GFPE. It is entirely a design decision. I wouldn't have put GFPE on that breaker, but that is my preference only.

What you are saying is confusing. In post #1 emergency 250A panelboard main breaker if lets say ground fault automatic disconnect with main breaker is Not provided where does it say ground fault detection is required? 700.6(D) is for 1000A or more. 700.31 clearly says source . Nothing about 250A emergency 277/48V three phase panelboard main breaker.

 

[hhsting]

Ok i read both sections.

NEC 2017 section 700.31 says Ground fault protection of equipment. The alternate source for emergency systems shall not be required to provide ground fault protection of equipment with automatic disconnecting means. Ground fault protection at the emergency source shall be provided in accordance with 700.6(D) if ground fault protection of equipment with automatic disconnecting means is not provided.

First above code is about Source for emergency system Not the downstream panelboard. I see source as like the generator. I dont know how this code section applies to post#1 question which has G ground fault dowmstream of source emergency panelboard?
Please anyone help as well

Am I reading the above incorrectly?


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[d0nut]

I thought my list working through your scenario was pretty clear, but I will try again directly answering the questions you posed.

What you are saying is confusing. In post #1 emergency 250A panelboard main breaker if lets say ground fault automatic disconnect with main breaker is Not provided where does it say ground fault detection is required?

Nowhere. GFPE is not required on that 250A circuit breaker. It is also not prohibited. It is entirely a design decision to include or exclude GFPE on that circuit breaker.

700.6(D) is for 1000A or more.

Correct.

700.31 clearly says source .

Correct.

Nothing about 250A emergency 277/48V three phase panelboard main breaker.

Correct. Nothing requiring it and nothing prohibiting it. The GFPE on that breaker is a design decision only.

 

[hhsting]

I thought my list working through your scenario was pretty clear, but I will try again directly answering the questions you posed.

Nowhere. GFPE is not required on that 250A circuit breaker. It is also not prohibited. It is entirely a design decision to include or exclude GFPE on that circuit breaker.

Correct.

Correct.

Correct. Nothing requiring it and nothing prohibiting it. The GFPE on that breaker is a design decision only.

Ok but where does it say if GFPE trip is not provided then GFPE detection is required to be provided for 250A panelbodd 480/277V three phase?

 

[d0nut]

Ok but where does it say if GFPE trip is not provided then GFPE detection is required to be provided for 250A panelbodd 480/277V three phase?

Nowhere specifically for that panel. If you want GFPE on that breaker, but do not want it to trip, then you have to have it alarm per 700.31 and 700.6(D). Go back through the steps I outlined in post #8. It walks through the steps for GFPE with automatic disconnection as well as what you have to do if you want GFPE without automatic disconnection. From a practical standpoint, what would be the point of GFPE that does not automatically disconnect the load or alarm?

But, to be clear, there is no code requirement for GFPE on that 250A breaker. The inclusion of GFPE, either with automatic disconnection or with the notification only, is entirely a design decision.