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antiqking 09-08-2008 09:33 PM

Design an outside underground electric system???
I am laying an underground electric line 60AMP from electric box on house 175 feet to a smaller box on a pole. I want to take smaller amp lines from the pole box to:

FIRST- a line 141' to 3 horse water warmers using 2.5 amps and 2 outdoor lights 150w each at least and 1 plug;

SECOND- a line from the pole box half way along the same line as the first and then turning off 24' to a 150w light bulb and 1 plug;

THIRD- a line going in the opposite direction 50' then into the stable 60’ for 2 water warmers and 2 lights 100w and a light 150w and 1 plug;

FOURTH- a line that follows the third line 50' then turns 40' to the barn for 2 water warmers and 2 outside lights of 150w each and 5 inside lights 100w or less each and 1 plug;

FIFTH- a line straight from the pole west 135' for 4 water warmers and 1 plug;
SIXTH- a line from the pole straight east 135' for 4 water warmers and 1 plug.
I do not know what size wires I should use in the six lines and if I should keep them separate or combine some of them or keep the outside lights separate from the warmers as in the summer I will want to use the lights and not the heat for the warmers. We would like to lay the pipe and wires ourselves and then call an electrician to connect them to the boxes.

Speedy Petey 09-08-2008 09:52 PM

If I were you I would:

A) Contact a few electricians to see if they will even do this for you.

B) If they will I would most definitely have them come out and layout the conduit runs for you.

C) I would NOT pull wire. Unless they will explain EXACTLY what wires to run and to where, you will almost certainly not get it right.

All this this can be done in 3 or 4 conduit runs, maybe less depending on terrain. Considering that, wire pulls are critical so that you don't waste time, money and material running redundant conductors.

The "hookups" as so many folks like to call them are NOT the hard part. The critical part is knowing what to run and where. Hooking up the boxes is easy.

antiqking 09-09-2008 12:23 AM

You are very kind to respond and I will take your advice. Thank you, antiq

Termite 09-09-2008 12:28 AM


Originally Posted by antiqking (Post 156368)
You are very kind to respond and I will take your advice. Thank you, antiq

Very smart move antiq! Good advice from Petey for sure.

antiqking 09-09-2008 12:35 PM

Thank you, Though I would like to have some ideas before the electrician comes. antiq

Stubbie 09-09-2008 03:38 PM

15 Heaters at 2.5 amps = 37.5 amps resistive...120 volts (?) (thermostat?)
Lighting load = 12.5 amps 120 volt

It's likely that all the heaters will be operating at the same time and only those lights that are needed will be operating, total if H's and L's if all operating at the same time is 50 Amps.

MY opinion based on all 120 volt loads.... use 4 20 amp multi-wire 240 volt branch circuits sharing a neutral...this is actually 2 opposite leg 120 volt circuits. Copper 12 awg THWN in conduit from the pole for the branch circuits. The multi-wires will reduce voltage drop considerably since you have a nice setup for balancing loads.

Hang a 3R 100 amp panel so that you have enough spaces for the breakers and branch circuits plus additional needs. Size the feeder to the pole and ocpd for 60 amps. For 175 feet 60 amps would need three #3 copper thwn to the pole with upsized ground wire probably a #6 awg. Any sizeable expansion in the future then size feeder for 100 amps and be done with it.

I didn't run the figures for an aluminum feeder probably #1 awg.

Now... this is just a quick look at what you have so a little closer look is probably prudent.

There is a lot more two this than may meet your eye besides wire size, it would take me awhile to go through it all.

antiqking 09-13-2008 11:28 AM

You are so kind to respond with so much information and wisdom. I will be glad to have this information when I talk to the electrician. Thanks a bunch. antiq

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