605.3 Fire Pump tap ahead of the service disconnect (12,470Y/7,200V)

[zemingduan]

Hi guys is the below design a code violation of the 695.3(A) (1)? This is a high rise building but not a multibuilding multi building campus-style complexes. The building is service by Atlantic City Electric.

The electric motor driven fire pump is also hooked to the generator emergency power via an ATS at the secondary of the fire pump dedicated transformer. The incoming electrical service is 12,470Y/7,200V 3ph 4wire service. The fire pump normal power is supplied from the tap/splice at the load side of the load break. I think this is a violation of the 695.3(A)(1) since it's not tap ahead of the service disconnect means.



Below is my proposal. I think this is code compliant. Let me know your ideas!

 

[david luchini]

I don't think the load break switch would be a "Service Disconnect."

Also, looks to me like the grounding switch is connected to the wrong side.

 

[zemingduan]

I don't think the load break switch would be a "Service Disconnect."

I was thinking about the same thing. But why it is not a "service disconnect" described in NEC? I can not find references or clues to persuade me to believe the load break is not a "service disconnect". Is it because that the incoming line bay/sections switchgear is utility switchgear not under the administration of NEC but another code? I don't know...

Also, looks to me like the grounding switch is connected to the wrong side.

The engineer from Square D Schneider Electric also tole me so. He said the grounding switch at the line side is not allowed due to the safety issue. But the one-line diagram example in the document "EQUIPMENT REQUIREMENTS FOR SINGLE SOURCE OR DUAL SOURCE MANUAL TRANSFER 12KV PRIMARY SERVICE" that Atlantic city electric sent to us show the grounding switch at the line side. And the ACE engineer states that is what they do for the grounding switch...

 

[david luchini]

I was thinking about the same thing. But why it is not a "service disconnect" described in NEC? I can not find references or clues to persuade me to believe the load break is not a "service disconnect". Is it because that the incoming line bay/sections switchgear is utility switchgear not under the administration of NEC but another code? I don't know...

Possibly the load break switch is Utility equipment, and their procedures make sure the line is de-energized before the load break switch is opened.

If it is utility equipment that would be an indication that it is not the service disconnect. But also, there is no overcurrent protection. Per 230.91, the service overcurrent device shall be an integral part of the service disconnecting means, or shall be located immediately adjacent to it. Per that section, the two fused switched would be the service disconnects.

 

[zemingduan]

Possibly the load break switch is Utility equipment, and their procedures make sure the line is de-energized before the load break switch is opened.

If it is utility equipment that would be an indication that it is not the service disconnect. But also, there is no overcurrent protection. Per 230.91, the service overcurrent device shall be an integral part of the service disconnecting means, or shall be located immediately adjacent to it. Per that section, the two fused switched would be the service disconnects.

Thanks for your opinions! This is a very good point. I agree with you. The utility company requires the load break switch to be locked and can be operated by their personnel only.

Does the below set comply with 695.3(A) (1)? I am not 100% sure about this. The fire pump is tapped ahead of the main service disconnect mean (the fused switch) and in a different vertical switchgear section. But are the separate switch gear sections considered different cabinets or enclosures?

 

[Engser18]

Hi guys is the below design a code violation of the 695.3(A) (1)? This is a high rise building but not a multibuilding multi building campus-style complexes. The building is service by Atlantic City Electric.

The electric motor driven fire pump is also hooked to the generator emergency power via an ATS at the secondary of the fire pump dedicated transformer. The incoming electrical service is 12,470Y/7,200V 3ph 4wire service. The fire pump normal power is supplied from the tap/splice at the load side of the load break. I think this is a violation of the 695.3(A)(1) since it's not tap ahead of the service disconnect means.

View attachment 2562338

Below is my proposal. I think this is code compliant. Let me know your ideas!
View attachment 2562341

There are another way to look at it, since you have two meters on both option 1 and 2, then it will be 2 separate services. Only fuse on option 1 is 10 A may not able to carry indefinitely lock rotor current of fire pump. On the option 3 you have one service with two disconnected mean. IMO they all meet code if the 10A fuse on option 1 is able to carry indefinitely lock current of fire pump.

 

[zemingduan]

There are another way to look at it, since you have two meters on both option 1 and 2, then it will be 2 separate services. Only fuse on option 1 is 10 A may not able to carry indefinitely lock rotor current of fire pump. On the option 3 you have one service with two disconnected mean. IMO they all meet code if the 10A fuse on option 1 is able to carry indefinitely lock current of fire pump.

You are right the 10E in option 1 is not correct. Thus I change it to 25E to carry indefinitely LRA of the 75HP fire pump. But I don't agree that 2 meters = 2 services. For a multifamily residential building, you only have one electrical service/ service entrance, but you can have multiple utility meters.

 

[Engser18]

You are right the 10E in option 1 is not correct. Thus I change it to 25E to carry indefinitely LRA of the 75HP fire pump. But I don't agree that 2 meters = 2 services. For a multifamily residential building, you only have one electrical service/ service entrance, but you can have multiple utility meters.

That still meet the code, bc technically the fuse switches after meter are service disconnected mean. Most utility are controlled everything before the meter doesn’t matter who is belong or own.
So the load switches aren’t considered service disconnected mean. You know why they do that right. And on the other hand, the load break switches are considered as isolating switches IAW 230.204 . And IMO it still meet NEC

 

[zemingduan]

That still meet the code, bc technically the fuse switches after meter are service disconnected mean. Most utility are controlled everything before the meter doesn’t matter who is belong or own.
So the load switches aren’t considered service disconnected mean. You know why they do that right. And on the other hand, the load break switches are considered as isolating switches IAW 230.204 . And IMO it still meet NEC

Yes. I agree with you and david luchini that the load break switch is not the service disconnect mean. The fused switches after the meter are the service disconnect means. Thanks for your opinions!