In article ,
Elmar wrote:
Just built a WW shop about 50' (cable length) from my service panel.
What gauge wire should I be using? 4-4-4-6? If so, should I pull
them all individually? Or buy the premade 4-4-4-6? What size
conduit? 1.25"?

Shop is 16X20, may consider a/c eventually too. Aside from that, I
have all the other goodies, Table Saw, dust collector, Compressors,
I'll need a ton of lighting, etc...

Would I ever really exceed 70 amps? Could I maybe get away with
6-6-6-6?

Thoughts? Experience?

Comment: cost of materials is relatively insignificant, compared to the
labor investment. 'over-engineering' is a cheap investment in future
upgradability.

Now, start budgeting the top-end (less may be sufficient, but consider 'worst
case' situations) energy needs:
lighting 5-8A @240
A/C 20-30A @240
Compressor 15-40A @240
Dust Collector 15-20A @240
Cabinet Saw 15-20A @240
Drill Press 5-10A @240
Jointer 10-15A @240
Planer 15-30A @240

Next, what all might be running at one time, _worst_case_.
obviously the lights, plus the air conditioning. The compressor
can be 'trusted' to kick in at 'the worst possible time'.
Add in the dust collector, and the the biggest hog power tool.
Wups! what if there are _two_ people in the shop. might have
two tools running. That puts the theoretical total draw into
the 100A range. which looks like 3 ga wire.

Obviously, one can 'get by' with less -- maybe the tools you have are
lower power; maybe you don't need to plan for two tools running; maybe
the compressor is run only when you actually need to use it -- you're
not keeping a pressure reserve on hand; etc., etc., ad nauseum.

Going 'oversize' on conduit is *not* a 'bad thing', either. makes pulling
the wires easier. And gives additional flexibility down the road. There
is something to be said for having the lighting on a _completely_ different
run from the main panel -- hit (or overload) the main breaker in the
sub-panel, and all the 'sharp stuff' powers down, *but* you can still see.
Also provides a simple way to 'lock out' the tools, without clobbering the
lighting.