Wiring Sub-panels

mntnvew · 01-04-2009, 01:43 PM

Hi All,

I just had barn built and in doing so I got a new meter w/standard 200 AMP service.

In order to provide power to the builders I elected to erect the main main w/meter on a couple pressure treated 4x4's.

Now that the barn is complete I want to run 2 sub panels. 1 for downstairs power (this is about 3 feet behind the current service panel on PT 4x4's). The 2nd panel is for the upstairs of the barn (this panel will be about 20 feet from the service panel).

Downstairs I will have 3 exterior lights and 3 interior lights and about 3-5 GFI outlets.

Upstairs I will have 5-7 outlets; 7 lights; 2 baseboard heaters AND an electric garage heater of some type (probably one of those ceiling mounted elec w/fan units 165000 BTU)

So you can see most of my draw will be coming from the upstairs panel.

First I wanted to get some folks opinions on the best way to do this.

And then, a few specific questions I had are:

1. What size wire should I use to run each subpanel's feed? 2 awg?

2. In the main panel will I have to piggy back breakers to get a sufficient amt of pwr to each sub panel?

3. What size sub panels would I need to power everything I needed off each sub panel?

4. What approach should I take when running the feed to the upstairs sub-panel? Should I put in it's own run from the main panel outside; or should I run it from the downstairs sub-panel?

Any other insight is appreciated.

TIA!

wirenut1110 · 01-04-2009, 02:21 PM

Unless it's a typo, your heater is gonna be almost 48,300 watts. Your service won't handle that. Looking at your other post, the heater you want to use is 17,100 btu's. In order to get 165,000 you'll need 10 of them @ 20.9 amps each.

mntnvew · 01-04-2009, 03:25 PM

Quote:

Originally Posted by wirenut1110

Unless it's a typo, your heater is gonna be almost 48,300 watts. Your service won't handle that. Looking at your other post, the heater you want to use is 17,100 btu's. In order to get 165,000 you'll need 10 of them @ 20.9 amps each.

It was a typo, see my other post for elec. heater type I am looking at purchasing. <http://www.diychatroom.com/showthread.php?t=35059>

wirenut1110 · 01-04-2009, 04:04 PM

How far away from the barn is your service? If it's a 200 amp outdoor main breaker with feed through lugs, I'd just install a 200 amp panel in the barn and run all the branches out of that. Seem too short of runs to put 2 subs in there. Just my opinion.

mntnvew · 01-04-2009, 06:24 PM

Quote:

Originally Posted by wirenut1110

How far away from the barn is your service? If it's a 200 amp outdoor main breaker with feed through lugs, I'd just install a 200 amp panel in the barn and run all the branches out of that. Seem too short of runs to put 2 subs in there. Just my opinion.

The service was run for the barn, I just stuck it on 2 - 4x4 pressure treated posts in order to get it up before the builders started the barn.

The barn is maybe 3 feet from the service.

As for "feed thru lugs" what are those? How can I tell if my service panel has these?

Thanks!