Subpanel from a subpanel? - Contractor Talk - Professional Construction and Remodeling Forum

DetailHandyman · 02-14-2009, 05:39 PM

Would there be any code or "bad practice" violation with running a subpanel off a subpanel?

I've got a 60A sub in the garage feeding lights & recepts, very lightly loaded.

Just had a new shed installed near the garage that needs lights and a recept or two for battery chargers.

Is it better to run direct single 120V circuit to shed from garage sub or feed 240V to a sub in the shed, from the garage sub? Run is about 65', 30' of it underground.

mdshunk · 02-14-2009, 05:42 PM

It's both legal and normal, and not bad practice.

Whether you run 120V or 240V to the shed is up to you, but I'd probably feed it at 240 since you don't know what the future holds and it's basically the same price. Put in a little 6 circuit panel, probably.

CNC · 02-14-2009, 05:45 PM

Cheaper to run a circuit out to the shed, if its just lights and 2 plugs, just run a 20A circuit out there, or maybe 2. I dont see a need for a sub panel?

mdshunk · 02-14-2009, 06:22 PM

Quote:

Originally Posted by CNC

2. I dont see a need for a sub panel?

So many people say that up front, but it sounds like he's probably doing it himself. There's literally going to be 25 extra bucks in putting a little subpanel out there. There's probably no "right" way to approach this, but a little wee subpanel in a shed is somewhat overkill, but certainly not uncommon. He's going to need a disconnect for that outbuilding anyhow since all that new jazz they added in '05, so it might as well be a sub.

rbsremodeling · 02-14-2009, 06:31 PM

Quote:

Originally Posted by mdshunk

So many people say that up front, but it sounds like he's probably doing it himself. There's literally going to be 25 extra bucks in putting a little subpanel out there. There's probably no "right" way to approach this, but a little wee subpanel in a shed is somewhat overkill, but certainly not uncommon. He's going to need a disconnect for that outbuilding anyhow since all that new jazz they added in '05, so it might as well be a sub.

I think this is how my last one went. Does this sound right?

200 amp in house
100amp sub in basement
60amp sub in detached garage

Magnettica · 02-14-2009, 06:36 PM

You never know what might be going in there one day so size up accordingly.

I would do 1 1/2" PVC conduit with (3) #6 THWN's and (1) #10 for the equipment ground.

Put it under a 60 amp double pole breaker for the main disconnect and don't forget to install a ground rod (#6 copper there too).

Phone/ cable maybe? Install additional conduit just for that too.

CNC · 02-14-2009, 06:41 PM

I took it like it was a little shed... just thinking keep it simple. But a tiny sub is not a bad idea, a 2 circuit panel. Here in CA, they would probably be saying "its just a little shed, but im going to have a few 1000w HPS running, a dehumidifier, and an air conditioning unit, and a few fans.....but its just a shed...." I get that a lot. wonder what for? haha

DetailHandyman · 02-14-2009, 07:12 PM

Thanks for the info, all!

I was leaning towards the sub. Just wasn't clear on the pros/cons of daisy chaining multiple subs.

CNC....

Maybe I mislead by saying "shed". Just the common terminology here in Amish country.
It's a 12' x 24' structure. Not on a permanent foundation, thus the "shed" usage. Gonna be materials storage for the business.

Quote:

Originally Posted by Magnettica

You never know what might be going in there one day so size up accordingly.

I would do 1 1/2" PVC conduit with (3) #6 THWN's and (1) #10 for the equipment ground.

Put it under a 60 amp double pole breaker for the main disconnect and don't forget to install a ground rod (#6 copper there too).

Phone/ cable maybe? Install additional conduit just for that too.

60A would probably be overkill. But you never know.
Actually I had considered the phone line thing.
Well, hell maybe I will install cable too.
Run some plumbing out there and gives me a place to hide when the wife gets her dander up.

Once again, thanks for the prompt replies!

Magnettica · 02-14-2009, 09:57 PM

Quote:

Originally Posted by CNC

I took it like it was a little shed... just thinking keep it simple. But a tiny sub is not a bad idea, a 2 circuit panel. Here in CA, they would probably be saying "its just a little shed, but im going to have a few 1000w HPS running, a dehumidifier, and an air conditioning unit, and a few fans.....but its just a shed...." I get that a lot. wonder what for? haha

Well in that case, install solar panels so the cops can't detect the extra kilowatt hours.

Magnettica · 02-14-2009, 10:02 PM

Quote:

Originally Posted by DetailHandyman

Thanks for the info, all!

I was leaning towards the sub. Just wasn't clear on the pros/cons of daisy chaining multiple subs.

CNC....

Maybe I mislead by saying "shed". Just the common terminology here in Amish country.
It's a 12' x 24' structure. Not on a permanent foundation, thus the "shed" usage. Gonna be materials storage for the business.

60A would probably be overkill. But you never know.
Actually I had considered the phone line thing.
Well, hell maybe I will install cable too.
Run some plumbing out there and gives me a place to hide when the wife gets her dander up.

Once again, thanks for the prompt replies!

Well then in that case since it's going to be mainly for storage, you might be best off running (4) #12's (black, red, white, green) and wiring up an interior and exterior light, a couple of receptacles, and whatever else. Doing it this way will keep your costs down and and still abide by the code.

LawnGuyLand · 04-11-2009, 08:19 PM

I ran 4 #8's to a shed many years ago (16?) and use this mainly for storage with a small workbench. I recharge a couple of garden tools and run some landscape lighting transformers. I wish I ran something larger to support temporary electric heat, for those long winter days when I'm itching to get something done out there but it's too darn cold.

scourt11 · 04-11-2009, 11:30 PM

sssssss

joelv1967 · 04-14-2009, 03:52 PM

Quote:

Originally Posted by CNC

I took it like it was a little shed... just thinking keep it simple. But a tiny sub is not a bad idea, a 2 circuit panel. Here in CA, they would probably be saying "its just a little shed, but im going to have a few 1000w HPS running, a dehumidifier, and an air conditioning unit, and a few fans.....but its just a shed...." I get that a lot. wonder what for? haha

Sounds like someone wants to grow hydroponic tomatoes

s.kelly · 04-14-2009, 04:25 PM

Built a garage at the house last year. Put in conduits for power and data plus 2 more cause it was fun!

After the ditch is there, there is not much money in PVC pipe

just my .02