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-   -   How much power can i give my new barn? (http://www.diychatroom.com/f18/how-much-power-can-i-give-my-new-barn-80607/)

DonQ2010 09-05-2010 04:32 PM

How much power can i give my new barn?
 
Got a new 24' X 40' barn for hobby and home project use.

It will have a 10' X 15' insulated room with outlets and ceiling fixtures inside the barn. I will probably want to use a room air conditioner and or a space heater.

In the rest of the barn I would want: 2 - 20A outlet circuits which I figure would be 4 double duplexes on each side of the barn on the main posts; and 9 - 4' shop lighting fixtures which I figure would go on two 3-way circuits from the doors. I have the usual hobbyist line of tools, a table, miter and circular saws, a compressor, small frig. I also would like to run a 240 for an AC-225 ARC welder.

I have a meter pole with a box under it with the 200 AMP main service cut off about 50' from the front corner of the barn. (By the way the house is an all electric 1400 sq ft manufactured home.) The box is a Murray with 2 catalog numbers LW004TR and LW204TL. It also has a 20 amp breaker going to an RV site also about 50' from the house. I have a picture of the label and the box but haven't figured out how to post it. If someone is interested I will email them to you.

I installed two 2" PVC conduit accesses before the barn floor was poured.

Now, how much of what I want to do is permissible to you guys. Then I need to know of what I can do: What size wire to the barn? Is the box at the meter adequate to provide service to the barn? What type of service box in the barn? Do barns require the circuits run through conduit or just conduit down to the boxes?

Ok guys, any takers?

Scuba_Dave 09-05-2010 04:37 PM

Have you completed a whole house power calc to see how your current status as far as power draw ?

I think I'd be inclined to run a 100a panel to the barn
What size wire depends upon the panel size & distance to the barn
50' isn't that far so voltage drop should not be a problem

a7ecorsair 09-05-2010 06:54 PM

Did your concrete guy suggest installing a UFER ground rod? Like already mentioned, I think you should put in a 100 Amp panel and I think it will be configured as a main. Is that 200 Amp cutoff a 200 amp breaker or is is a just a disconnect switch?

vsheetz 09-06-2010 04:22 AM

Do a search on subpanels - a very common question here. Also check out the stickies for some excellent wiring diagrams.

bobelectric 09-06-2010 04:59 AM

Reads like 100 amp would be good.

DonQ2010 09-06-2010 08:25 AM

How much power can i give my new barn?
 
Thank You very much Gentlemen!

I will get a inductive current attachment for my meter to determine what my approximate house power usage is and consult the group again.

DonQ

Scuba_Dave 09-06-2010 09:15 AM

Quote:

Originally Posted by DonQ2010 (Post 496662)
Thank You very much Gentlemen!

I will get a inductive current attachment for my meter to determine what my approximate house power usage is and consult the group again.

DonQ

For a 100a feed THWN you would need #3 wire

Actually you are required to do a load calculation
This would be the peak possible power use as an approximation
You could actually use far more then this calculation

This thread has an excel spreadsheet used to perform a load calculation
There are others out there
http://www.diychatroom.com/f18/nec-n...-2008-a-65447/

An Inspector may require that on Inspection
So far my Inspector has not required one...but I have it
I also have a 200a feed, oil heat

DonQ2010 09-06-2010 02:59 PM

How much power can i give my new barn?
 
Scuba, where is this excel spreadsheet to calculate loads? That thread appears to only go to some of your NEC links.

Thanks,

DonQ

frenchelectrican 09-07-2010 01:01 AM

I know you are working on new building but the word Barn will you have any livestock in there like Horse or other aminals in there ?

If so that will change the rules a bit if that the case one of us will fill out the reqirement due they are pretty strict on it.

Merci.
Marc

Scuba_Dave 09-07-2010 07:32 AM

Quote:

Originally Posted by DonQ2010 (Post 496818)
Scuba, where is this excel spreadsheet to calculate loads? That thread appears to only go to some of your NEC links.

Thanks,

DonQ

Post #8 has the spreadsheet

DonQ2010 09-07-2010 11:09 AM

How much power can i give my new barn?
 
No animals but dog and me. It's actually a barn because of it's first name, as in Pole?

DonQ2010 09-07-2010 11:11 AM

Nope. Call me dull, but I see no link to any excel spreadsheet, only NEC data.

DonQ2010 09-07-2010 11:23 AM

How much power can i give my new barn?
 
To a7ecorsair, I would say it is a breaker, labeled 200 AMP, looks like a big horizontal wall switch.

a7ecorsair 09-07-2010 11:39 AM

Quote:

Originally Posted by DonQ2010 (Post 497206)
To a7ecorsair, I would say it is a breaker, labeled 200 AMP, looks like a big horizontal wall switch.

LW004TR MURRAY 200A 4/8 TRLR PNL MD PROVLOADCENTER: MAIN BREAKER; 120/240 VAC, 208 VAC STAR/120 VAC; 200 AMPERE; 8 MAXIMUM CIRCUIT(S); (4) 1 INCH MAXIMUM SPACE(S); INTERRUPTING RATING 22000 AMPERE; BACK FEED LOCATION; NEMA 3R, OUTDOOR ENCLOSURE; SIZE 20 INCH L X 11-1/8 INCH W X 4-3/4 INCH D; APPROVAL UL 50, UL 67; APPLICABLE STANDARD NEMA PB-1
LW004TR MURRAY 200A 4/8 TRLR PNL MD PROV
- MURRAY - LW004TR | LW0




It is a Main Breaker panel and has room for four 1" breakers. I assume that two of the breaker spots are in use for your home, one in use for the RV site, which leaves one empty. Is this correct?
If so, it won't work for feeding a sub panel in your shop.
Is the RV site necessary?

DonQ2010 09-07-2010 02:30 PM

How much power can i give my new barn?
 
I wish I had a picture of what you want me to understand. I see that there are 4 - 1" breaker location hole provisions on the right side in the panel cover under the disconnect, 1 of which, is being used for the 30 amp to the RV site. Inside there are provisions for 8 breakers under the disconnect, 4 on each side. What is the configuration of the device to provide the 100AMP feed to the barn? Wouldn't it be similar to the 200A disconnect, connecting across both bars? Do you have a site I can go to to look at the breaker or device as it applies to my existing box. I am also not opposed to changing the disconnect box as well if it would address a code upgrade or discrepancy.

Could I run the RV connection from the barn using this disconnect box?

DonQ


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