tenant metering enclosure expansion question

[mjmike]

We have a project where there is a 1200A meter enclosure with 5 meters; each at 200A. It is located on the outside on the end of a strip mall. There are 4 units each separated by a fire wall. We are correcting an incorrect installation so the current configuration is not a factor. 2 of the units have two (2) 200A services. When done, the load will not increase. We are going to remove the (2) 200A services from the 2 units and install a single 400A service into each of these. Now, my question on the metering setup. Right now, there are 5 meters in the enclosure each with their own breaker. Because the enclosures are only good for 200A meters, we need to add on an additional section for (2) 400A meters. Once done, unless we remove an existing section, there will be (2) 400A meters, (2) 200A meters, (3) blanked off sections. Breakers still add up to not exceeding 1200A rating.

First, keeping with the 6-disconnect rule, do the blanked off spaces come into the equation since the breaker is there but no meter? Next, what is somebody sees down the road they can add on and there are (3) 200A slots available. Now the potential exits for exceeding the 6 disconnect rule and exceeding the enclosure ampacity.

So do we remove 1 existing section and replace with 400A section so meter count does not exceed 6 or keep the section blanked off expecting the next person to check the NEC prior to adding on?

 

[petersonra]

We have a project where there is a 1200A meter enclosure with 5 meters; each at 200A. It is located on the outside on the end of a strip mall. There are 4 units each separated by a fire wall. We are correcting an incorrect installation so the current configuration is not a factor. 2 of the units have two (2) 200A services. When done, the load will not increase. We are going to remove the (2) 200A services from the 2 units and install a single 400A service into each of these. Now, my question on the metering setup. Right now, there are 5 meters in the enclosure each with their own breaker. Because the enclosures are only good for 200A meters, we need to add on an additional section for (2) 400A meters. Once done, unless we remove an existing section, there will be (2) 400A meters, (2) 200A meters, (3) blanked off sections. Breakers still add up to not exceeding 1200A rating.

First, keeping with the 6-disconnect rule, do the blanked off spaces come into the equation since the breaker is there but no meter? Next, what is somebody sees down the road they can add on and there are (3) 200A slots available. Now the potential exits for exceeding the 6 disconnect rule and exceeding the enclosure ampacity.

So do we remove 1 existing section and replace with 400A section so meter count does not exceed 6 or keep the section blanked off expecting the next person to check the NEC prior to adding on?

Just my opinion. What someone might do down the road is not a code violation today. It would be low on my list of things to worry about. They could do all kinds of things that violate the code. You can't stop them. You are only responsible for what you actually do.

 

[JDBrown]

Just my opinion. What someone might do down the road is not a code violation today. It would be low on my list of things to worry about. They could do all kinds of things that violate the code. You can't stop them. You are only responsible for what you actually do.

I agree. If somebody wants to put a meter in the blanked-off sections at some point in the future, they're going to have to go through the POCO, which (I hope) means there would be an inspection. Any Inspector worth his salt will notice right away that there are more than 6 disconnects.

If you had to plan for everything someone might do in the future, it would paralyze you very quickly. I've seen a few installations where a MLO panelboard with 6 breakers is connected to the secondary of a transformer (SDS). What's to stop somebody from coming along later and adding a seventh circuit breaker to that board? Nothing, if the Code isn't being enforced. But it's not the responsibility of the Electrician who installed the panelboard.

... do the blanked off spaces come into the equation since the breaker is there but no meter?

This question is a bit tougher. I don't think the blanked off spaces should be counted at all, since they're not connected to the utility. However, this question would probably be worth a call/visit to your Inspector just to verify. You'd hate to have your client ready to move in only to fail the final over something like a blanked off meter.

 

[mjmike]

All good points.

 

[GoldDigger]

This question is a bit tougher. I don't think the blanked off spaces should be counted at all, since they're not connected to the utility. However, this question would probably be worth a call/visit to your Inspector just to verify. You'd hate to have your client ready to move in only to fail the final over something like a blanked off meter.

Unless it is totally obvious which five or six handles are the actual disconnect ts and which are dead, I would have a hard time arguing with an inspector who calls this a violation.