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· Banned
31 Posts
Discussion Starter · #1 ·
Hi im 17 years old and taking up electrical trades program at a junior vocational school.. im currently rehabing my barn and got everything roughed in now.. using 100 amp CH panel and put 2 cieling fans and 4 t8's 8 ft fixtures in i currently have the panel backfed from my generator and powering it.. now i want to run service cable from my house up there..i was thinking 2 2 4 URD to carry the load since its about a 500 ft run and do a direct burial? now my only question is should i have the power company drop another 100 amps into my house and place a disconect and then run urd from the house up to the barn underground and go up the mast into an LB into the panel or how should i go with doing this..anythng would help also you can call my work cell at 937 684 6621

· " Euro " electrician
5,369 Posts
500 feet ?

That is pretty long run for plain jane URD cable and I don't think the 35mm² { #2 } will cut it espcally if you load up pretty nice.

I get 80 % of service size ( 80 amp ) you will need at least 120mm²{ 4/0 } alum to prevent serious voltage drop.

The other option is that you can talk to the POCO to ask them to hook up a second drop { some will do that for small fee and some case it cheaper than try to trench 500 feet plus the 35mm² conductors }


· Banned
2,487 Posts
are u sayin having poco drop a 100 amp line into the barn from the pole which is 500 feet and have them put a meter in?
That's one option. however, if the pole is 500' away, they will want to add another pole in between. But if you do dig a trench and lay URD, you should use 4-wire, instead of 3. And if you do dig a trench, be sure to check for other utilities first. Also, I'm sure you got this inspected, right:whistling2:

4,975 Posts

Generally speaking when using secondary URD in a quadplex there is no equipment ground wire when you are configuring for an underground 4 wire feed. You could remark one of the phase conductors as the egc if you are allowed by the inspector.

I think maybe going with some other underground quadplex like aluminum mobile home feeder would be more appropriate.

You may or may not want 4 wires though I would strongly suggest that you run 4 wires in the event you have the barn supplied with other metallic paths like metal water lines or data cables. In which case a 4 wire feeder is required by code.

You havent elaborated to how your present service is configured. Your options vary depending on what you have with your present service to your home.

For example is your home drop coming from a pole with meter?

Or is the meter on the house?

Where is the main disconnect located... out by the meter and pole?

Or is it located at the house?

If it is at the house is it a outside meter main panel or is your home panel inside the house?

These things will determine the better options for getting power to the barn as a diy project.

The next is what your loads will be at the barn now and for future plans.

The other order of business is what is your present service size? And how heavily is your present service loaded? Hot tubs, electric heat.. any of those? Or electric tankless hot water heat?

Next #2 aluminum URD or #2 aluminum anything will not get proper voltage to the barn at 500 feet. Your going to have a 30 volt or so loss at 100 amps.

Generally speaking 100 amps will require 4/0 al at 500' distance.

60 amps which would be plenty for most non commercial or non agriculatural barns and cut your wire size in half.

Some conversations with your power company or inspector may reveal some options you weren't aware of....:thumbsup:

just my opinions
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