Use second 200 amp panel as sub in pole barn??

[tapout187]

Hey guys first of all thank you so much for all of the wonderful info you all share on here it's been incredibly helpful with my build. I am in new jersey anr have been trying to truck along on my pole barn build for a while now as money can provide. My question for you all is I have a 200 amp square d QO panel in my house and bought a second same exact panel for my pole barn. From what I thought I learned here was I could put say a 100 or 125 amp breaker in my house panel and run 1-1-1-6 as a feeder to the panel in barn. I had an electrician/ friend of the family come over to take a look to see about helping me get power to the barn. He said "absolutely not" can I use the 200 amp panel in the barn because of the capability of it versus the feeder size (he said if it was inspected the inspector would never pass it. I understand what he was saying I just thought that if I was only feeding it with the way 100 amp breaker in the house to start with then that's what I would have even though the main breaker on the sub would say "200 amp". Please let me know what you guys think I truly appreciate it!!!

 

[rockwithjason]

totally false. what matters is the size of the breaker feeding the panel and the wire size between the two. if this is a separate building you will need a main disconnect or main breaker at the sub panel

 

[pattenp]

You can use a 200A main breaker panel as a subpanel fed from a 100A or 125A breaker with wire sized for 100A or 125A. The 200A main breaker in the subpanel becomes no more than a main disconnect.

 

[theoldwizard1]

Why would you spend the additional $$$ for a 200A panel if you don't need it ?

All QO panels take the same breakers.

 

[tapout187]

Thanks guys that's pretty much what I thought and I by no means am an electrician just trying to be an educated consumer through this site. Now I know this will turn into a "stepping on toes" kind of thing so is this an NEC allowable practice. I was just really surprised how adamant the guy was that I couldn't do it the way I want. I just figured for the extra money I would always have breaker space. Oh also is the #6 good for the ground (1-1-1-6)?

 

[tapout187]

Oldwizard I guess I didn't feel it was that big a deal in the big picture to know I'd have breaker space....

 

[pattenp]

1-1-1-6 aluminum is okay for a max of 100A. 125A will require the wires to be larger.

 

[tapout187]

Thank you so much patten I have learned a ton from your posts thanks for helping me out!!!

 

[wyliesdiesels]

Your "electrician" friend is wrong!

No code forbids that setup.

How long is the feeder?

#6 AL egc is good for upto 100a...

What type of wire are u getting?

Dont forget ground rods, a ground bar and to remove the bonding screw on the neutral bar.

 

[tapout187]

Haha Wyliesdiesels it seems crazy to me how a "licensed" electrician could be so sure of something and act like I'm the crazy one. As far as feeder length it depends which way I run it. If I go though the house and crawl it's about 200 ft (and I'd need two different wire types I gather). If I go straight out from panel and cut across the yard it's about 150ft. Do you think I should be concerned with voltage drop?

 

[wyliesdiesels]

Haha Wyliesdiesels it seems crazy to me how a "licensed" electrician could be so sure of something and act like I'm the crazy one. As far as feeder length it depends which way I run it. If I go though the house and crawl it's about 200 ft (and I'd need two different wire types I gather). If I go straight out from panel and cut across the yard it's about 150ft. Do you think I should be concerned with voltage drop?

A license just means that the person could pass a test and someone vouched for them.

My last boss was licensed and didnt know the difference between a neutral and a ground. He didnt understand the difference "because theyre bonded at the main service panel"... *facepalm* :

Now what your friend may be referring to is a local ordinance so ask him if the local AHJ is the one who forbids it. But i cant see why they would.

150' would be fine with #1 al but 200' is pushing it... And u will have considerable voltage drop at full load...

What do u plan on running in the barn?

If u go through the house and use individual conductors they would have to be in conduit....

 

[Norcal]

What is the odds of the shop being used at full load? With a home shop pretty unlikely.

 

[bczygan]

I'm doing the same in a 1 car attached garage. The 200A QO sub panel will be 30' from the 200A QO main panel. 90A breaker in the main and appropriately sized wire to feed the sub, plus all the other correct things.

Bill

 

[pattenp]

Just some rough numbers but with #1 Al at 200ft pulling 70A will be at about 3%VD, 100A will be a little over 4%VD. 3%VD is the recommended VD limit, but 5% is the max you'd want to have. At a 150' you're good to the full 100A staying around the 3%.

 

[tapout187]

As far as what do I plan on running out there... I mainly will do welding (mig/tig)/fab work. I will have a 2 post lift, 220 compressor, I would love to someday get an ironworker machine. For the most part realistically nothing more than anyone else on here in their one man back yard shop. I understand I myself can only use one machine at a time. I just cant help but to think about when my father and a friend are over and I'm welding another one is grinding and puts car up in the air on lift and the compressor kicks on all at the same time. At this stage in the game I just want to build to prepare for the worse and I definitely like to overkill a little....

 

[tapout187]

Patten thanks a lot for those numbers. Definitely gives me something to think about. I'm leaning towards going through the yard (as long as a I plan ahead good enough). Now just because I am a person who likes to overkill everything a little do you think it's not a bad idea to step up the feeder (to I think 2/0) and just go with 125 amp out to the shop. Not that it matters too much to you guys but my garage is 36x46x13 with gambrel attic roof trusses.

 

[theoldwizard1]

Oldwizard I guess I didn't feel it was that big a deal in the big picture to know I'd have breaker space....

BIG difference in price ! I can not imagine needing more tha 24 circuits in a garage !!

QO 125A 24 spaces/24 circuits - $53 @ HD
QO 125A 32 spaces/32 circuits + 5 20A breakers - $123 @ HD

QO 200A 30 spaces/40 circuits + 3 - 20A single pole and 2 - 30A double pole breakers - $173 @ HD

 

[Pwrgeek]

BIG difference in price ! I can not imagine needing more tha 24 circuits in a garage !!



QO 125A 24 spaces/24 circuits - $53 @ HD

QO 125A 32 spaces/32 circuits + 5 20A breakers - $123 @ HD



QO 200A 30 spaces/40 circuits + 3 - 20A single pole and 2 - 30A double pole breakers - $173 @ HD

For $50 now (out of what is probably a $60-70k build OP can confirm) you are going to screw yourself for later. In my shop (about the same size) I have 32 circuits used before I've even done a thing. They are:

Single poles
Lighting A
Lighting B
Outlets north A
Outlets north B
Outlets south A
Outlets south B
Storage room outlets
Storage room lights
Office area outlets A
Office area outlets B
Office area lights
Clean room outlets
Clean room lights
Bathroom outlets
Bathroom lights
Bathroom heater / vent

Double pole
Compressor
Lift
Welder
Outdoor RV outlet
Hot water heater
Mill / lathe(VFD)
AC (mini split) A
AC (mini split) B

So on a 40 space panel I'm already down to 8 spares and I haven't even moved everything in and started using the shop. I seriously considered a 72 space panel but those are some serious $$$ so instead I already made a place to put another 40 space sub if I need it. Point is you'll use more than you think.

 

[theoldwizard1]

6 circuits for lights ? Okay maybe Lighting A and B are switch via the breaker, but 4 additional unique circuits for lighting ? A circuit just for bathroom lights ??

Although, with the 5 breakers included, the difference in cost between the 125A and the 200A is about ZERO !

 

[^&right]

When I did my shop I had a 200 amp panel in the house feeding a 15A wire to the shop done years ago. I had a 200A panel installed in the shop and a 400A (actually 325A IIRC) split meter installed that few both panels. Power company set a new pole on their dime and installed a 50K transformer on my pole for a few hundred bucks. 25K is standard for homes around here. Showed them the power I was planning on pulling as the shop grew and they hooked me up.

Perhaps a split meter is the way to go for you? One power bill, no upcharge, and you get 2 200A panels. I think I paid a total of around $1100 to the power company to bury new line, transformer, and hooked to the new meter.

 

[tapout187]

Pwrgeek thank you couldn't have said it better myself!!

 

[Pwrgeek]

6 circuits for lights ? Okay maybe Lighting A and B are switch via the breaker, but 4 additional unique circuits for lighting ? A circuit just for bathroom lights ??

Although, with the 5 breakers included, the difference in cost between the 125A and the 200A is about ZERO !

Lighting A and B are the main shop lights and each circuit will have around 1200W on it (what can I say I work late into the night and I like a bright workspace) plus I would never put all the lights for such a large space on a single circuit (safety concern one popped breaker and I have to try to walk to the panel in the dark). The individual circuit per room is more about being able to isolate and work on things individually later without impacting things going on in other areas. I like things being broken up to make it easy on myself later when it is time to change a fixture.