Adding a Transfer Sw and Stand alone Generator to an existing residential service.

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spizeii

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Is there any way legally to add a transfer switch and generator to an already installed residential 200A panel? My buddy (another electrician) and I were trying to figure this out, but we work mainly on Industrial jobs and lack "the residential knowledge" and code. Also, he's trying to prevent pulling the meter or working on the line side of the 200A breaker.

This is his suggestion/plan:

You have your Meter Pan which feeds your panel. Now this may sound ludacris, but bear with me. Install a sub-panel next to your main and transfer all your branch circuits and breakers to this sub-panel which will have a 200A main breaker. Install a 200A 2P breaker in your Main Panel which now only contains your Main 200A Breaker/Disconnect. Run conduit/wires to a Transfer Sw (prob a MTS) from Main Panel and from Generator. Then run conduit/wires from Transfer Sw to new Sub-Panel.

New 2P 200A breaker will act as disconnect to transfer switch "normal" side. Main breaker on generator will be disc for transfer sw "emergency" side (unless a Disc Sw between the Gen & TS is required). You still have a means of disc in your Sub-Panel with a 200A main.

All sounds good to me, but as I stated already, I'm not up to the code on residential and he doesn't wish to work live or pull the meter.

If ANY of this is even legal, please let me know. Or, if anyone knows of a different approach, I'm all ears!

Thanks!
 
As I read the elaborate "plan", it seems a lot of trouble to avoid pulling the meter and the most probable reason I can see would be to avoid POCO involvement and inspection, so I will decline to assist in the endeavor and encourage others not to do so.
 
stickboy1375 said:
http://www.interlockkit.com/


which is much easier than what you described above, which I'm not even sure I followed...:)
Click to expand...

I followed it but now I have a headache.
This is the bottom line for your install.
The transfer switch must be service rated (breaker built in) or there must be a utility disconnect before the transfer switch.
If you install a ATS the generator must be able to carry the full load that is transferred or you must have load shedding ability. 702.5(B)(2)
You also need to look at 702.11 for the generator disconnect which takes you to 225.36

Now if he hasn't bought the ATS yet then do as Stickboy said go with a interlock making it a manual system. Then he can chose what to run.
 
Or, you can go with an "essential circuits" system similar to this one :

http://www.electricgeneratorsdirect.com/Generac-Guardian-5871-Standby-Generator/p4785.html

That way you only have to transfer the circuits that you consider necessary. The xfer switch is built into the sub-panel. No pulling the meter, no load shedding, you don't have to provide that inspector with connected load calculations, no re-working of the existing panel (i.e separating grounds and neutrals). In short, a whole lot easier. The generator comes with a 5' whip and connection port. The sub-panel/xfer switch comes with a 30' whip for connection to the generator and a 2' whip for connection to the main breaker panel.
 
I think your going to find that most panels that allow branch circuit breakers will not allow a 200 amp breaker to be installed, the stabs in the panel will not support that kind of amperage.

I have seen 400 amp panels that would only allow up to a 150 amp two-pole breaker.

Square D did have some QO style breakers that went all the way across the panel taking up 4 breaker spaces, but I haven't seen them in a while.
 
augie47 said:
As I read the elaborate "plan", it seems a lot of trouble to avoid pulling the meter and the most probable reason I can see would be to avoid POCO involvement and inspection, so I will decline to assist in the endeavor and encourage others not to do so.
Click to expand...

I agree with you.

I also want to add that just because it is a dwelling doesn't mean the rules for installing a generator are any different. Main difference is in a dwelling the size of switches, overcurrent devices, and conductors are usually smaller than a lot of other places, notice I said usually.

If you get into legally required systems it gets more complicated, optional standby is optional standby no matter where it is installed.
 
For this application the only residential code that would modify what you are used to is 310.15(B)(6).
I would get a 200 amp TS that is service entrance rated, install between the meter and existing panel.
You'll need to provide the AHJ a load calulation to show the generator can carry the entire calculated load, per the 2008 NEC.
 
tom baker said:
For this application the only residential code that would modify what you are used to is 310.15(B)(6).
I would get a 200 amp TS that is service entrance rated, install between the meter and existing panel.
You'll need to provide the AHJ a load calulation to show the generator can carry the entire calculated load, per the 2008 NEC.
Click to expand...
This is correct. As I understand (NEC 2008) 702.5(B)(2)(a) you would be required to provide the AHJ with a load calculation for the entire connected load. Under 702.5(B)(2)(b)where the xfer switch comes equipped with a load management system you do not have to provide that information to the AHJ. My understanding is that anything that would be energized "automatically" under an emergency condition would have to be managed through the load management system. If a HO wants to run their 40A double wall oven during a power outage that's another story and a larger generator.

Someone please correct me if I'm wrong.
 
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