James Waldby wrote in
:

On Thu, 01 Oct 2009 08:48:10 -0600, SteveB wrote:
I need to run about 190' from breaker box to my shop. I have a
double pole breaker on a 200 (+ or -) v. that says 30 on each leg.

In the shop, I will be running a SP175+ 220v MIG Lincoln welder rated
at 22 amps, but that only when cranked fully open. Most of the stuff
is half that. I will be running about four shop lights, radio, and a
power tool or two at any given time. My electrician buddy has
suggested IIRC a #6 wire.

#6 copper is perfect for 30 or 40 amps at that distance. Go any bigger
and you will likely have problems fitting it in the breaker you have.


Does this sound adequate?

Adequate I guess for what you have mentioned - so far.
Personally I like to size home shops for 60 amps. That allows a buzz
box welder or 5hp compressor motor to be used without trouble. There's
nothing like finding a great deal on a tool and realizing you don't have
enough juice to run it. #2 aluminum would be good for 60 amps at that
distance, probably similar price to the #6 copper.


Do I get the bundled wire, or use the
separate strands? How much voltage drop on that far? Is #6
marginal, or should I slightly oversize?

Use underground rated cable unles you are prepared to deal with pull
boxes and conduit bending and assorted stuff to pipe everything from
panel to panel. Cable lets you run through the house and bend easily as
many times as you need to get into the conduit just before it goes
underground.

My charts show less than 3% drop on #6cu at 30 amps for that distance,
that's pretty good.


(Also see ebay # 180398856402, appears
to be 300' 3-cdr #0000 Al, around $1.58/ft when you count shipping.)

Too big to be worth the effort, at nearly any price.


Bundled wire would be easier to pull but might cost a little more, and
with heavy current it heats up a little more than not-bundled wire.

Cable is physically harder to pull - more weight and less flexible.
Heat is irrelevent when the wire is upsized for distance like this and
burried and never going to see continuous full load.


Mike (my electrician) will put the right thing, snip

Get him to tell you what cable or wire to shop for. He will be familiar
with your house and be best to advise which method to choose.


I think ebay prices (about $2/foot for #6-3+ground; search for romex),
even with shipping,snip

Romex isn't suitable for underground. Even if it is in conduit it needs
to be a wet location rated cable or conductor to be in the ground.