What are some of the rules for secondary electric lines between the transformer and the main panel? The lines would be carrying 100a at 220v. Could they be placed on the ground or do they have to be buried? Would placing the lines in a PVC conduit allow them to be set on grade?
I ask, because between where I’d like to set a ground mounted transformer and the building site is a 50′ high bluff. Because of rock and slope it’s not possible to bury the lines. The slope is steep enough that you can climb it by using the trees as hand holds. If minimal cover was required, I guess it could be hand dug, but it would be a miserable job. I know that above ground would be a better solution, but I’d rather not clear out a swath of trees. Amoungst other problems (access), the electric company also anticipated having to blast a couple of holes which is something I’d like to avoid. Obviously, the installation would be by a electrician, I’m just trying to determine what is feasible.
Certified boat fetish.
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Generally (but not always) the lines from the transformer to the meter at the house are installed based on the local electric utility's specifications, which won't necessarily follow the NEC. However, it's hard to imagine any utility would allow installing them in a conduit laid on the ground. Each utility has its own rules, so you really need to hash it out with them, but I'm guessing overhead lines will be the best solution.
Ok, that makes sense. Lets say that I go above ground, then I could set the transformer at the top of the hill and shorten my secondary line. However, I still need power at the base of the hill. Do power companies allow you to run private power on their poles? I'm thinking not, but then again, this is on private service.
Certified boat fetish.
I'm not sure I understand your situation. Fortunately, I don't have to.
Visit your Power Company's planning/engineering department, and ask them. What do they say? Chances are, your situation falls under the NESC, in which case the lines will have to be either 20 ft. over or 5 ft under the ground.
I don't understand why you're setting a transformer; those are usually the power company's concern. The only 'private services' I can think of are major industrial locations - and on such a job you're certain to have assorted professionals involved.
You say it's a jobsite, which leads me to think this place needs temporary power now, followed by a proper electrical service later. That's a pretty common thing, and, again, you'll have to involve the power company for a temporary power drop.
Anything different, and I'd have to say that you need licensed professionals ON SITE, and that this is the wrong place to ask for advice.
Edited 11/17/2009 1:53 pm ET by renosteinke