Sub-panel feed

mntnvew

Hi all,

I have a standard 200 AMP service for my barn I just recently had built, it goes to a panel w/8 slots and the meter. I wanted to put a panel inside the barn, so I went to HD and purchased a similar model to Square D Company 200 Amp 40 Circuit Panel Box. I also installed 2 inch sch 80 from the outside panel to the inside panel. There is about 8 feet total from one panel down into the ground and back up to the inside panel.

What side wire? I assume #3 will suffice?

My exterior panel that has the meter has 2 GFI outlets and 6 open spaces. What size breaker do I install in one ore more of the remaining spaces? Does the #3 wire hook to the breaker effectively?

For the record I am only running the power and will not be doing the final juice up, but the electricians in my area charge me for questions... UGH!

Any other advice/comments are greatly apprecaited!!

Thanks

Steelhead

You would need a double-pole breaker. It will take up two spots. The size breaker depends on what your needs are in the barn. What will this panel be supplying?

mntnvew

Well it is a raised center barn. in the lower area were the stalls are I will have 3 exterior stall lights; 4 interior recepticles (should I GFI them?); 1 exterior GFI recepticle; 2 interior overhead lights (probably the large exterior pole type lights); 2 exterior man-door lights; 1 exterior barn light above the garage (large pole type light from hardware store).

In the raised center, upstairs, I will have my basic shop, I MAY use an electric heater up there but not sure yet. So I want lots of lights upstairs; 10 recepticles.

That is about it I believe.

Stubbie

I'm not sure why you wanted a 200 amp sub panel with 40 circuits. The 6 spaces in your meter main would have provided 12 branch circuits at 120 volts using single pole tandem style breakers.

But you say you 'wanted a panel inside' and bought the 200 sooooo your not going to be able to supply it with 200 amps unless you have feed thru lugs on the meter main panel outside. I really think you should take it back and get a 100 amp main lug sub-panel with say 12 spaces 24 circuits. Then you could install a 100 amp breaker with #3 copper hots #3 copper neutral and a #8 ground. Remember if you run a sub-panel from the meter main you need a 4 wire feeder with neutral and ground unbonded in the sub-panel. If you do not understand what this means please ask questions.

Do you have the model number and manufacturer of your meter main??

__________________
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Stubbie

chris75

What type of barn is this? Is this a agricultural building?

chris75

This would only fly if that meter main is attatched to the building. Not sure if it is or not.


Does it really matter if he bought a 200A or 100A main lug? Either one will work just the same. Its only a disconnect at this point.

mntnvew

It is a pole barn, 3 stalls downstairs w/hay & storage and a small work shop upstairs.

Right now the barn is 40 wide by 36 long, next summer I will be adding another 36 feet doubling the length of th barn.

It has horses in it so I guess it can be called agricultural.

mntnvew

So since I can basically just keep this and use it as is, I can follow this direction and take a 100 AMP breaker and the #3 copper for hots and neutral and #8 ground and that will do it?

PS - 4 wire? there are only three. Also what is unbonded?

PSS - I will get the model # and manufacturer tomorrow as it is a ways to the barn. Thanks!

Stubbie

Chris I think he said it was and was only 8 feet to the 200 amp sub-panel location inside. If I'm wrong then you are right.




Yeah I agree but will he ever use 40 circuits? Plus he has 12 available at the meter main assuming it is attached (I think it is). It is just a matter of design and effective usage but your right it doesn't matter.

__________________
" One nice thing about the NEC articles ... you have lots of choices"

Stubbie

Stubbie

Yes provided the meter main is attached to the barn. Otherwise there are a few other things to consider. So is it attached to the structure of the barn?

Yes probably three to your meter main but if the meter main is attached to the barn then you must run two hots a neutral and a ground to your sub-panel (4 wires). At the sub panel you need to seperate the neutral and ground. How you do this varies from panel to panel but the attached diagram gives you the basics. the neutral bar must not be bonded to the metal of the panel. If your panel is a Square d then that is usually a green screw that installs thru the neutral bar and threads in to the metal of the panel back. You do not install it instead you add a ground bar to the panel, you will see holes in the panel back that are swaged where ground bars are added. You then terminate the feeder ground and branch circuit grounds to that ground bar and neutrals of the branch circuits go to the neutral bar. Since the bonding means isn't installed in the neutral bar this keeps you from bonding the neutral to ground.





Probably isn't going to be necessary if you just want to run 100 amps to the sub panel

mntnvew

The meter is attached to 2 4x4 pressure treated posts that the electric company came and installed, I just ahd to purchase the materials. It is about 30" from the side of the barn, so it is not 100% attached to the barn. HOwever the elec. guys said that since it was a pole barn and the meter is attached to two pressure treated posts, it is considered attached to the barns foundation... yeah yeah but they said it to me without my proding.

Does that change things?

The diagram ROCKED, thanks a lot for that! I can see what you mean now with 4 wire.
PS - I am in RURAL SW Montana and have very little to worry about code wise, but I still want to make sure it is done correctly and up to code.

Stubbie

Sounds like they may do it that way and consider it attached. About the only thing that changes if considered detached is a disconnect is required at the barn sub-panel and a ground rod. Sounds like you have a 200 amp main breaker panel so that would be the disconnect. Plus there is a 6 disconnect rule that is applied by some jurisdictions to sub-panels but I'm not going to go into that. It simply means if you don't have a main single throw disconnect 'on' the barn or in the sub-panel and not more than 6 throws of the hand to turn of all breakers in the sub then that qualifies as your barn disconnect.
Personally I think you should consider it attached and do things the way the diagram shows. Do they have a ground rod at the meter main?

__________________
" One nice thing about the NEC articles ... you have lots of choices"

Stubbie

Stubbie

Some other things to know



The term “general-purpose receptacles” isn’t defined in the NEC, but the intent is that GFCI protection isn’t required for receptacles installed specifically for equipment such as brooders, incubators, feed mixers, feed grinders, feed conveyors and the like.

Equipotential planes a generally installed under concrete floors where livestock are confined. You probably do not have this but just a heads up.

__________________
" One nice thing about the NEC articles ... you have lots of choices"

Stubbie

mntnvew

Yes there is a ground rod at the meter main.

Thanks Stubbie for all your help!!!!

mntnvew

OK, I checked out the main panel it is a Seimans Rain Proof side by side. It DOES have feed thru lugs.

With that said what approach should I take now? Does it change using feed thru lugs?

2 runs of #3 wire + #8 ground into the "sub panel" and into 2 100 AMP breakers in the sub panel's "main breaker" break out? The breakout is rather large I assume this is because it requires 2 100 AMP breakers, is that correct?

Or do I just run it to the lugs in the sub panel and be done wiht it?

Thanks!