Six or less disconnects for main service

[jaylectricity]

I have seven spaces to be separately metered. One of the spaces will be 208/120 3ph and the rest will be part of two 3-position meter sockets, 3ph in/2 ph out.

Would putting the 6 meters after a 600A safety switch and the one 3ph meter on a meter/main socket qualify as having two switches to disconnect the service? Maybe if they were properly labeled?

Something like this:



And does that 600A disconnect have to be fused if there is a main breaker on each position of the meter socket?

 

[jaylectricity]

Picture not to scale, the safety switch is much larger than that, and the equipment would be rearranged.

So that brings up another question...if the 3ph meter is on the other side of the 6-pos meter bank would it be too far from the safety switch to be considered "grouped"? Maybe better off putting it to the left of the safety switch.

 

[jaylectricity]

Total calculated load for the whole service is about 601 208/120 3ph. I'm considering sizing the service conductors based on that, but a couple of the spaces have not been determined other than HVAC and general lighting and receptacle load.

I've got a whole spread sheet on the price of various size conductors, various size and number of conduits, including whether two sets of parallel conductors can fit in one conduit and the adjustment factor for 4+ ccc in conduit.

 

[packersparky]

That would be two disconnects and would be acceptable. I see an issue with two services supplying one building unless you meet one of the conditions in 230.2.

 

[electrofelon]

That would be two disconnects and would be acceptable. I see an issue with two services supplying one building unless you meet one of the conditions in 230.2.

The discussed installation would not be 2 services, it would be one service with two sets of service entrance conductors per 230.40 exception #2.

Would putting the 6 meters after a 600A safety switch and the one 3ph meter on a meter/main socket qualify as having two switches to disconnect the service? Maybe if they were properly labeled?

I agree with packersparky, perfectly acceptable. I did something similar recently: One set of service entrance conductors to a MLO SUSE panelboard with 5 disconnects, and another set of SEC to a MB service panelboard = 6 total. In this case each panelboard was on opposite sides of the CT cabinet. Just to be safe, I had some phenolics label made up, the MLO was "service disconnects 1-5 of 6" and the other one "service disconnect 6 of 6". Only your inspector/AHJ can give you a true definition of "grouped".

I am curious as to the metering arrangement of the mixed single and three phase. I have contemplated this but never done such a job. Is that standard to just use three phase sockets everywhere? I always thought you could "mix and match" single and three phase stacks (I assume the single phase stack alternates the feed to the individual sockets to maintain balance).

 

[jaylectricity]

I am curious as to the metering arrangement of the mixed single and three phase. I have contemplated this but never done such a job. Is that standard to just use three phase sockets everywhere? I always thought you could "mix and match" single and three phase stacks (I assume the single phase stack alternates the feed to the individual sockets to maintain balance).

In my situation, it's not mix and match, but I see what you're saying about that. For this job, the customer wants to have a three-phase panel because there are existing 3ph exhaust fans and one 3ph A/C condenser that he wants to use. Believe me, it's stupid. He should just replace the condenser with a much higher efficiency condenser and replace the two exhaust fans.

But his insistence on the 3ph is going to help us with the rental spaces.

We're only offering single-phase to each rental space. And most of them are only going to be using 120V equipment.

 

[jaylectricity]

If you get 3ph in and 1ph out you can really expand the available service.

So you have a A B C phases. Each space only gets two.
So one space is AB
Another space is BC
and a third space is AC.

So you get three spaces with 200A single phase, but you only need 400A at three phase to feed them.

 

[packersparky]

The discussed installation would not be 2 services, it would be one service with two sets of service entrance conductors per 230.40 exception #2.

The NEC would consider it two services if the meter enclosures were supplied from different transformers and it would be a violation. If they are supplied from one transformer and meet the conditions in 230.2 it would be considered one service.
230.40 exc. No. 2 would not apply to the conductors on the load side of the overcurrent protection, as the conductors are not service entrance conductors they are feeders.

The conductors supplying the meter enclosures are not service entrance conductors by definition, they are service conductors.

 

[jaylectricity]

The NEC would consider it two services if the meter enclosures were supplied from different transformers and it would be a violation. If they are supplied from one transformer and meet the conditions in 230.2 it would be considered one service.
230.40 exc. No. 2 would not apply to the conductors on the load side of the overcurrent protection, as the conductors are not service entrance conductors they are feeders.

The conductors supplying the meter enclosures are not service entrance conductors by definition, they are service conductors.

It's one service, they all run back to the same padmount and are tied together.