Installation of generator 400 amp ATS service rated

ricksan76

Member
I've been a residential electrical contractor for years, and I'm just now getting into generators and I wanted to pick some brains around here and see how other electricians would go about installing a transfer switch into this scenario in the picture. It's a 400 amp semi-flush, underground fed main panel POCO wiring is in conduit coming up through the cement slab obviously inside the wall, and into the left section of the meter main combo. Surface mount mains are easy and simple, but what method would you use in this application, and how would you do it? What would be the simplest least amount of damage to the area way of doing this? Any help would be appreciated. My thoughts are adding a meter socket box to the left of it, then the ATS to the left of that. My issue is getting in and out of the wall with 400 amps. It's likely 3" conduit coming up for POCO.
 

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Buck Parrish

Senior Member
Location
NC & IN
When you said 400 I expected to see two 200 amp disconnects. Do you only have one 200 amp panel?
It has a sticker stating Unicorn . That's a breaker styled like a Federal Pacific.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I would explore intercepting the wiring inside the building.

What's behind the wall where the feeder and the LB seem to meet up?
 

Buck Parrish

Senior Member
Location
NC & IN
It looks like their may be a panel behind the panel, 230.72 violation. If so pull it back out bring it to the left of the gas meters set the ats their and just refeed the inside panel. Just speculating.
 

Todd0x1

Senior Member
Location
CA
It looks like their may be a panel behind the panel, 230.72 violation. If so pull it back out bring it to the left of the gas meters set the ats their and just refeed the inside panel. Just speculating.
Did zinsco ever make 2 sided panels? Square D used to have (maybe they still do?) these csed panels with meter and a few breaker spaces on the outside and a loadcenter on the inside all in one piece. They were popular with tract home builders.
 

ricksan76

Member
When you said 400 I expected to see two 200 amp disconnects. Do you only have one 200 amp panel?
It has a sticker stating Unicorn . That's a breaker styled like a Federal Pacific.
It's a 400 amp panel. It has a 200 amp breaker feeding a sub panel in the garage. On the other side of the house. A 100 amp breaker feeding another sub panel about 20' away. It is a unicorn. It also has a 60 amp breaker for the solar.
 

ricksan76

Member
I would explore intercepting the wiring inside the building.

What's behind the wall where the feeder and the LB seem to meet up?
The other side of the was is the inside of the home. All wiring from the main panel is underground from the bottom of the panel straight into the concrete to the sub panels. POCO wiring comes in the same way
 

ricksan76

Member
It looks like their may be a panel behind the panel, 230.72 violation. If so pull it back out bring it to the left of the gas meters set the ats their and just refeed the inside panel. Just speculating.
No panel behind it. Behind it is the living room. If it was a garage or utility room, no problem.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
It looks like you need to either recess the ATS in the wall to the right and use a straight nipple, or cut a chase in the wall to the right of the bottom of the enclosure, and rig an offset nipple to the surface.
 

Todd0x1

Senior Member
Location
CA
I don't see how you can legally intercept the service conductors between the meter and the breakers. It would be nice to be able to just land a couple lugs where the buss is bolted on now and pipe over to a new panel but I doubt that would be legal.

What about using two ATS a 200A and a 100A and nipple out the right side of the can into a deep 3R box that protrudes through the wall and pipe out of the exposed portion of that into the two ATS?

I think I'd be looking for a way to get rid of the zinsco while I was at it. Have you measured the existing meter main and compared its dimensions to the modern 400A meter/main combos? Perhaps you can remove this, install a new semi-flush in the hole, and pipe out of the exposed part of the semi-flush over to your ATS(s)
 

ricksan76

Member
I haven't measured, but the last time I took one of these out I remember it had a channel in the middle so that it fits between 2 16" on center studs.

What I was thinking is putting a 3R pull box low inside of the wall and sticking half way out then going to a meter box. I wanted to draw something out, but I'm on my phone right now and not at home. SCE can seal it. Not sure if they would let that fly out not.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I get it. Sink a box deep enough to nipple into within the wall, and tall enough to nipple out of on the surface.

Basically, an offset that's as deep as (or deeper than) it is wide. Maybe a 6x6x6 plastic box like this:

1614453785706.png
 

Todd0x1

Senior Member
Location
CA
I haven't measured, but the last time I took one of these out I remember it had a channel in the middle so that it fits between 2 16" on center studs.

What I was thinking is putting a 3R pull box low inside of the wall and sticking half way out then going to a meter box. I wanted to draw something out, but I'm on my phone right now and not at home. SCE can seal it. Not sure if they would let that fly out not.
Hmm, if sce won't do that (fellow sce customer here) I wonder if you could intercept the service conduit in the ground and bring it up on the surface of the wall into a new surface mounted meter box.
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
It's hard for me to provide suggestions without being onsite seeing the details but don't forget the PV needs to be connected on the LINE side of the ATS. The PV cannot be active when the generator is on.

Also in my area if you treid to moidify that service you would be required to relocate it. Besides not meeting NEC working clearances the panel must be at least 30" from the gas regulator.
 

farmantenna

Member
Location
mass
how did that installation ever pass inspection? Will you be required to move it away from the gas meter if you touch it? We could never put any of that equipment that close to a gas meter here in Massachusetts.
 

ricksan76

Member
how did that installation ever pass inspection? Will you be required to move it away from the gas meter if you touch it? We could never put any of that equipment that close to a gas meter here in Massachusetts.
When I saw the gas meter there, I wondered the same thing. But then again it is on Indian land and the Bureau of Indian affairs is who issues permits and inspects. So that may have something to do with it. I will find out though. Yeah, for the PV, I'll be installing a relay. I'll just have to put it on a plan and see what they say.
 
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