On Mon, 22 May 2006 17:03:58 -0400, John Grabowski wrote:

"Ignoramus18798" wrote in message
...
I presently have a 220V subpanel in my garage, the circuit is wired
with 6 gauge wire on a 60A circuit breaker.

This circuit is inside a 3/4" conduit. It is comprised of three 6
gauge wires (two hots and neutral, with conduit being the ground).

I now realize that choosing that low capacity was a mistake. (with a
big welder now in the picture) I would like to know just what would be
involved if I wanted to upgrade to 100A.

Can I be able to squeeze, say, two 4 gauge conductors (hots), plus one
8 gauge conductor (neutral), into a 3/4" conduit? Or will I have to
replace the conduit too?

I am very regretful of not doing the right thing and going for max
capacity. When I did it, the only 220V tool I had was a 3 HP
vertical compressor.

i


I seem to recall suggesting that you use 1" conduit when you posted
questions regarding the installation of your subpanel.

Your memory is excellent, and I was wrong.

You can remove everything that you have already installed and put in a 100
amp subpanel circuit or you can run a new circuit just for the welder. The
book says that you can install 2-#4's in 3/4" emt. I think it would be a
tight squeeze with another conductor for a neutral.

Got it. Perhaps staying within my current setup is the wisest choice.

Check the label on your main panel to see what is the maximum permitted
circuit breaker as that may influence your decision. The main panel may not
be rated for a 100 amp circuit.

Will do.

I recommend that you pick up a copy of the National Electrical Code (NFPA
70) and figure out what your options are. You can buy the code book on
Amazon.

Thanks John.

i