200a ATS vs 150a service

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LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I looked at a job today. Customer has a 150a service, meter outside, MB panel inside, with what appears to be 2/0 al SE cable.

Customer ordered a 24kw Generac (new model) and a 200a ATS. I will need to replace SE with SER and separate the bonding.

My question is: Since the ATS will have a 200a main, won't I have to use 4/0 SER all the way to the 150a breaker in the panel?
 
Already ordered, and I'm not part of that process. I just wanted to confirm that I can not size the feeder according to the breaker at the load end like a tap.

I could tell the SE cable was larger than 2, but smaller than 4/0 even before I went inside. The 150a panel's buses are a messy mix of neutrals and EGC, too. :rolleyes:

Plus, the panel is way beyond the "nearest the point of entry" and should have been installed as an outside-main/inside-sub-panel service to begin with.

Besides, I already have a partial spool of 4/0 al SER.
 
LarryFine said:
Already ordered, and I'm not part of that process. I just wanted to confirm that I can not size the feeder according to the breaker at the load end like a tap.

I could tell the SE cable was larger than 2, but smaller than 4/0 even before I went inside. The 150a panel's buses are a messy mix of neutrals and EGC, too. :rolleyes:

Plus, the panel is way beyond the "nearest the point of entry" and should have been installed as an outside-main/inside-sub-panel service to begin with.

Besides, I already have a partial spool of 4/0 al SER.
Click to expand...

Up-sell a panel swap if it's a mess?


SceneryDriver
 
Right now, there is only the meter outside, even though there should be a main disco in my opinion, and the 150a main breaker in the panel. The SE drops about 2' under the meter, then into the crawl space, and about 15' in and up to the panel in the hall.

There is also a 10- or 12-circuit manual T/S above the panel; the kind with individual 3-position switches for each circuit, and the like-numbered black and red wires, along with a single neutral and a single EGC. I took a few pics, which I'll post in a bit.
 
IMO it is a tap. If it meets the rules for a tap then you can use smaller conductors.

You could also get an enclosed circuit breaker and put it in line just downstream of the ATS. probably be cheaper just to make the conductors bigger if you got to replace them anyway.
 
Yeah, I think most places would not allow unprotected conductors to run that far inside to a panel. They should have used a meter main originally, I am assuming you don't need to change the service drop.

The code never specified a maximum length from the meter to the panel. Rule of thumb around here is 10' or one stick of pipe. I had to do one once that was about 8' and the inspector balked. I finally got him to agree but I had to run rigid from the meter to the panel
 
conductors from weather head, thru meter to line side of ATS will need to be 200A, 230.90. Conductors on load side of ATS is now feeder, needs to be 4 wire and either 200A or use one of the feeder tap rules.
 
electrofelon said:
conductors from weather head, thru meter to line side of ATS will need to be 200A, 230.90.
Click to expand...
I plan on calling this an upgrade so the POCO will do their part at no charge.

Conductors on load side of ATS is now feeder, needs to be 4 wire and either 200A or use one of the feeder tap rules.
Click to expand...
Agreed, and as I said earlier, it should have been 4-wire to begin with.
 
Am I also correct that load shedding is necessary? In my pic, I see the following circuits that it applies to:

Heat
A/C
Water heater
Range

Am I correct that load shedding is only required for loads that would cause overloading? For example, if the A/C, heat and, range are disabled, the water heater may remain connected without load calculations?
 
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