Generator Installation: Replace meter base? SER vs Conduit? Judgment calls

[MusicMan]

Situation:

Installing a 20kw Generac generator with 200 Amp service rated Nexus smart transfer switch. (already been through the threads about weather or not to separate the DC control and AC feeder conductors - What a headache)


Existing service setup:

Main distribution panel is on an interior wall that forms a T with the exterior wall. Main service cable is 4/0 SE fed through the rear knockout of the meter base passing through probably three studs before it hits the main panel. Poco feed is underground service lateral (see photo)

SER vs/ Conduit

I'm planning to bring the new 4-wire service feed out of the bottom of the transfer switch through a 2' length of 2" PVC, LB into the crawl space then come back up under the main panel. Still deciding between sleeved SER or full run of conduit to the panel using #2/0 CU. It will be about a 15' run of cable for both methods.

-Advantage of SER: Less labor, no need to worry about coming up dead center beneath the main panel, as there are existing cables there.

-Minor hitch with SER: Bending radius not kosher with 338.24 for even the biggest LB, though I've never seen it enforced here in VA on services. I can fit it in a big $$ 2-1/2" lb without using a sledgehammer (I tried it at Lowes ). I could maybe use a 90 elbow but that would likely involve hours of messy hammer drilling and patch work on the brick to get it to come out level with the surface.


-Advantage of full conduit run: No problems with bending radius using 2/0 thhn cu. Looks nifty from inside the crawl space .

-Disadvantage of full conduit run: More labor and $$, (will need to sleeve up beneath the panel in sections)

The Meter base:



Removing the old SE cable will leave the knockout abandoned so If I keep the existing meter base, I'll need to plug the knockout with a $$ seal tight plug. And then patch the hole in the wall. Of course, to do that I'd have to remove the meter base from the wall. So, looks like I'll need to call Dominion anyway to have them de-energize the socket so I can safely work on it. Also, if you look closely at the photo, whoever installed the enclosure didn't use the engineered mounting holes. They just drove masonry nails straight through the back. So the base is flush against the wall with no clearance behind it.

I'm not sure if Dominion power carries an offset meter socket theses days. I know that model's been retired for a wile (ring lugs instead of the "lay-in and clamp" type). All the new one's that I've installed are centered. They also restrict which knockouts were're allowed to use. So I might be better off staying with this one.


Comments? Suggestions?

 

[ActionDave]

I would go with a full run of conduit.

 

[Vector]

What if you pull the existing SE cable out of the main panel and run it into the transfer switch mounted inside? Then run 1 1/4" pipe from the transfer switch out to the generator?

BTW, Generac has changed their rules and allows you to run the control wiring with the power in a pipe of any length now.

 

[masterinbama]

The 200 amp UG Milbank sockets used here have the utility connection to the left of the meter. Can you get one of those in your area and then you would have room for your service disconnect and transfer switch to the left and run through the wall as it is now.

 

[goldstar]

I've had this situation this before. I would nipple into the side of both the meter pan and the xfer switch (use water-tight lock nuts). Run your 2/0 CU off the load side of the meter into the xfer switch. Come out of the bottom of the xfer switch into the house with SER or PVC (whatever works best for you). As far as the existing SEU cable I would pull out the wires, leave the fitting in place and use a conduit cap bushing. Don't have to call the POCO or pull the meter pan off the wall.

 

[jumper]

The 200 amp UG Milbank sockets used here have the utility connection to the left of the meter. Can you get one of those in your area and then you would have room for your service disconnect and transfer switch to the left and run through the wall as it is now.

In VA Dominion Power provides the meter base free and I am pretty sure that you have to use theirs.

Never heard of someone buying or using anything else. I suppose the OP could ask.

 

[MusicMan]

I've had this situation this before. I would nipple into the side of both the meter pan and the xfer switch (use water-tight lock nuts). Run your 2/0 CU off the load side of the meter into the xfer switch. Come out of the bottom of the xfer switch into the house with SER or PVC (whatever works best for you). As far as the existing SEU cable I would pull out the wires, leave the fitting in place and use a conduit cap bushing. Don't have to call the POCO or pull the meter pan off the wall.

Unfortunately the fitting was installed with the threads out and the clamp in. I might be able to wedge something behind the panel to hold the connector ring still while I twist the squeeze fitting out.

Hmmm. I don't suppose I could use a gasketed "screw bar" type with the bar side out?

http://www.garvinindustries.com/ele...s/knockout-seals-(screw-bar-type)/kos-200-vt#

 

[MusicMan]

Also, thinking about using a LB (LR if it's made in 2") out the bottom of the meter to the transfer switch since the switch is so tall that going directly out the side would put the breaker about 6' off the ground.

Here's the basic plan in photoshop form.



Generator feed will be 1 1/4 PVC. 20' of which will be buried. Will attach LR or PVC J box to 4 x 4 post then a 3' seal tight flex whip to the generator.

Generator maximum rated load of 75 Amp and has 90AMP (previously they had 100) breaker on on unit. Will be "whole house" with managed AC / Range loads. I had planned on running #4 THHN CU, treating this a s a service feed and going by Table 310.15(b)(6).

 

[masterinbama]

Also, thinking about using a LB (LR if it's made in 2") out the bottom of the meter to the transfer switch since the switch is so tall that going directly out the side would put the breaker about 6' off the ground.

Here's the basic plan in photoshop form.



Generator feed will be 1 1/4 PVC. 20' of which will be buried. Will attach LR or PVC J box to 4 x 4 post then a 3' seal tight flex whip to the generator.

Generator maximum rated load of 75 Amp and has 90AMP (previously they had 100) breaker on on unit. Will be "whole house" with managed AC / Range loads. I had planned on running #4 THHN CU, treating this a s a service feed and going by Table 310.15(b)(6).

That looks good, pull the lock nut off the clamp, shove the extra back in the wall and plug it with a blanking bushing that was mentioned above.

 

[MusicMan]

Thanks for the comments. I decided to go with the full run of PVC conduit. Spent almost 4 hours (including breaks) with a hammer drill and a crowbar to get a hole big enough for 2" conduit to fit through.

Anyway, while I wait for miss utility to spray the dirt, a question regarding the flex conduit.

I was all set to use LFNC when I realized that I've never seen a non metallic connector fitting for 1 1/4 flex. I've only seen metal fittings for sizes above 1" If I transition from my PVC conduit to LFNC via a conduit body and use a metallic connector at the transition, that metallic connector has to be bonded somehow, correct? If I use LFMC, instead would the metallic connector at the PVC transition then be considered bonded by way of the conduit to where it connects at the generator frame?

(Sorry about being OCD with this. It's my first generator installation. :angel: )

 

[Daja7]

Aside from the meter thing, make sure your clearances are correct. 3 feet from end of enerator to any obstrucion such as walls and plants. Gen needs to be set on a 5" gravel base or some other acceptable base like concrete pad or pavers, not the ground.