Need help with the tap rule

[Pceja007]

Hi all,

First time post.
I am performing an installation at a convenience store in a mixed use building. Commercial on the lower floor, residential units above. There is a 400 Amp service coming into the building landing at a 400 amp disconnect. This 400 amp disconnect feeds a 225 amp disconnect about 3’ away. The 225 amp disconnect feeds the 3 apartment meters and disconnects, along with the existing meter and disconnect for the convenience store. I am attempting to increase the service capacity of the convenience store to 200 amps. I’d like to install 2 feeders off of the 400 amp disconnect ( one for the existing 225 amp panel and one to a 200 amp meter and disconnect panel for the commercial unit.
I have 2 questions:
1) can I increase the capacity of the convenience store to 200 amps or only 175 amps ? Given that there is already a 225 amp panel in service.
2) can i go to the meter and then OCPD from the feeder tap at 400 amp disconnect? i know the code says I need to land on a correctly sized OCPD, would going to the meter first violate the code ?
any useful help greatly appreciated.
thanks

 

[LarryFine]

Welcome to the forum.

1) can I increase the capacity of the convenience store to 200 amps or only 175 amps ? Given that there is already a 225 amp panel in service.

These questions depend on calculated loads, not breaker rating totals, just like a breaker panel. So, unless both sub-panels are maxed out, you're fine with the 200a second breaker.

2) can i go to the meter and then OCPD from the feeder tap at 400 amp disconnect? i know the code says I need to land on a correctly sized OCPD, would going to the meter first violate the code ?

The NEC effectively views a meter as a lump in the service cable. I'm curious about the OCPDs you have ahead of the existing meters now. That's typically a power company thing.

Perhaps I'm not understanding your question. You started with tap questions in your thread title, but you didn't ask one that I saw. The meter doesn't change the tap allowances.

 

[Fred B]

Hi all,

First time post.
I am performing an installation at a convenience store in a mixed use building. Commercial on the lower floor, residential units above. There is a 400 Amp service coming into the building landing at a 400 amp disconnect. This 400 amp disconnect feeds a 225 amp disconnect about 3’ away. The 225 amp disconnect feeds the 3 apartment meters and disconnects, along with the existing meter and disconnect for the convenience store.
any useful help greatly appreciated.

Sounds like this is a case that there is sub-metering set up?

I have 2 questions:
1) can I increase the capacity of the convenience store to 200 amps or only 175 amps ? Given that there is already a 225 amp panel in service.

No matter the setup the determination as to whether you can add another load or not, is determining the cumulative loads present already. This is not number or size of individual breakers, but by an actual calculation or by a demand metering to give peak high over a period of time. If your cumulative existing loads plus desired added new loads do not exceed the capacity of the existing service, then adding the additional panel and loads permissible. One cannot simply just put in another panel.

2) can i go to the meter and then OCPD from the feeder tap at 400 amp disconnect? i know the code says I need to land on a correctly sized OCPD, would going to the meter first violate the code ?
any useful help greatly appreciated.
thanks

Really having trouble visualizing what you are trying to do overall.

I am attempting to increase the service capacity of the convenience store to 200 amps. I’d like to install 2 feeders off of the 400 amp disconnect ( one for the existing 225 amp panel and one to a 200 amp meter and disconnect panel for the commercial unit.

Why meter separately the new suggested panel? Are you adding load or are you just trying to meter separately the commercial space and only leave common loads on the 225A panel as a "house" panel?

 

[Pceja007]

Thanks for the reply Larry.
1) the total load will not exceed the 400 amp main disconnect

2)
The NEC effectively views a meter as a lump in the service cable. I'm curious about the OCPDs you have ahead of the existing meters now. That's typically a power company thing.
- currently, there are 6 tap splices made off of the load side of 225 amp panel( in a gutter can). These 6 splices feed 6 meters, that feed 6 disconnect panels, that feed 6 sub panels. 4 residential and 2 commercial units, i am working on one of the commercial units.
- I would like to remove the meter and disconnect feeding the market I am working on (from the existing 225 amp disconnect ), and tap into the load side of the 400 amp disconnect to feed a 200 amp meter and then a 200 amp breaker or fused disconnect to feed my unit.

Perhaps I'm not understanding your question. You started with tap questions in your thread title, but you didn't ask one that I saw. The meter doesn't change the tap allowances.
- the tap question I have is, since I will be installing a feeder tap off of a 400 amp ocpd to supply a 200 amp service, am I allowed to go to the meter before landing on the 200 amp ocpd? the code states that the feeder tap must land at an Ocpd. All of the other meters and disconnects installed on site have the tap feeder splice going to the meter and then the disconnect, i spoke with the on duty electrical inspector and he stated the code, which says it needs to go to a ocpd first and then the meter and then my sub panel. Seems weird to me. I’ll ask the inspector that comes out for my rough inspection to chime in before I install this portion of the service.
Thanks again for your input.

Welcome to the forum.

These questions depend on calculated loads, not breaker rating totals, just like a breaker panel. So, unless both sub-panels are maxed out, you're fine with the 200a second breaker.


The NEC effectively views a meter as a lump in the service cable. I'm curious about the OCPDs you have ahead of the existing meters now. That's typically a power company thing.

Perhaps I'm not understanding your question. You started with tap questions in your thread title, but you didn't ask one that I saw. The meter doesn't change the tap allowances.