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Martin H. Eastburn Martin H. Eastburn is offline
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Default Electrical supply sanity check...

Use a Nylon line - small rope so you can drag what you want.
A good string of nylon will pull in a rope to pull in what not.

My 2-phase high voltage lines are just over 1000'. I have 7 poles.
Two drops (was three). I have a pole beyond my house drop. That pole
has two old junker transformers from the power company - an output winding
was bad or such - it is to absorb spikes made from the main line.

I have two meters - two transforms - one for the shop and one for the house.

Each place has 220 split like is normal. The shop has my build 3 phase services
as well.

Martin

Jim Stewart wrote:
Ecnerwal wrote:
Hey, it's on topic - lots of metal in long squiggly bits, and it's
going to my shop...

I'm throwing 300 amp service (one phase, all there is out in the
woods) at my new shop building, having finally gotten past various
hurdles that caused me to think for a long time I was going to have to
make it be off-grid. Eventually 100 amps will come off that to the
eventual house, if that ever eventually happens.

It's about 335 feet of run, plus running from the pole-mount
transformer to down in the ground, and back up to the meter at the far
end. It's on the cusp of 400 or 500 MCM copper, and I'm probably just
going 500 to be sure. Can't run primary underground per the power
company rules (I can't. They can, but they won't, or they price it so
high that I won't, comes to the same thing in the end). Something like
370-390 feet of wire.

Conduit figures to 3" min, I'm thinking 4" - not only more room, but
possibly one of those bigger is not more expensive (might even be
cheaper?) if it's the more common size things - don't know for sure.
Yes, I'll be dropping in some spares while I have the hole open. Well,
at least some extras - the price I'm being estimated on the large
conduit (PVC) seems high - $5/foot? The 4" plumbing stuff is only
about $2/foot last I recall, and while I expect electrical to cost a
bit more, more than double seems high. That may preclude a spare for
the big stuff. At least one empty smaller run as well as the phone
line run.

Anyway, while I'm pondering prices, does $5.67/foot sound like a
reasonable price for 500 MCM copper when buying 1100-1200 feet
(370-390 X3)? My electrician has been saying his suppliers have cut
prices drastically with the slowdown in building and/or China
(depending what you think drives copper prices more), but only got to
specifics once the run length was nailed down.

I've saved Bruce's previous advice about getting copper bus bars in
the breaker box and making sure it's industrial interchange, rather
than some oddball custom breakers. What other advice have I forgotten,
before it's too late? I don't know that an air line in the trench
makes a lot of sense, as the trench terminates halfway up the
driveway. I should be able to tie the ground network into a 100 foot
well casing. Should I run a ground all around the outside of the
building, and if so, is #4 adequate for that? Too late for a Ufer on
this building.

I do have a licensed electrician working on this, but I value a second
opinion...it's a big chunk of the building fund on one aspect.


Leave an extra pull cord in the conduit if
you can. It will probably be all rotten
and tangled if you need it, but who knows..