In article , "Bill" wrote:

"Doug Miller" wrote in message
...
In article , "Bill"
wrote:

"Doug Miller" wrote in message
...
-- but why are you using 12-3 cable? (12-3 has *four* conductors:
black, red, white, and bare.)

For this particular wire run, I'm going to power 8 duplex outlets with one
hot and 4 more with the other hot.

Why not 6 and 6?

Well, it's really 4, 4 and 4. I thought the 120 quad above the 220v for the
TS could share, and the other quad would run from a circuit dedicated to it. Having the two
duplex halves of a quad running off of totally separate circuits seems downright dangerous (because
its confusing)!

Right, that's not a good idea.


There's no need to run 12-3 or 10-3 for pure 240V outlets. A 240V circuit does
not use, and hence does not need, a neutral conductor, so 12-2 or 10-2 will
work just fine.

I could run my two 120v branch circuits from one 12-3 cable and a tandem
breaker. Is there much advantage to two cables and two breakers?

It depends mostly on the locations of the recepticals -- if you can run one
continuous cable from the breaker panel to the first one to the last one, it
may make more sense to use 12-3. If you have to split it in two different
directions, use two separate runs of 12-2.

As a non-professional, I suspect the price structure favors one 250' spool
of cable.

No, it doesn't. You "suspect". But apparently you haven't actually checked.
Prices this morning at Lowes.com show $118 for 250' of 12-3 and $70 for 250'
of 12-2.

Plus, 12ga wire is inappropriate for about half of your wiring job. It's
unnecessary for your lighting circuit(s) -- those can use 14ga easily. And you
_really should not_ use 12ga wire for your 240V circuits. I assure you, you
will come to regret that decision. I *strongly* recommend using 10ga _at
minimum_ on the circuits for your table saw and air compressor.

Others have suggested 12-3 (partially, for the unforeseeable future, I
think), in addition to the fact that you get two 120v branch circuits from one cable).

That's really not as big an advantage as it seems. Especially when you can run
168 feet of 12-2 for the same price as 100 feet of 12-3.

I intended to install only 20 Amp circuits everywhere--however
Joseph brought up some new issues concerning this to my attention. My TS
wants to be on a 20 Amp circuilt. I understand 12 gauge wire is suitable for that
(10 being required only on 30 Amp circuits, from my understanding).

That's correct... but what if you decide to buy a larger, more powerful table
saw at some time in the future? I cannot emphasize this too strongly: don't
make decisions now that will constrain your decisions in the future. Run 10ga
wire to your 240V outlets.

I need to assimilate some of this. I'll keep thinking!

It might be helpful to discuss concerns relating to putting lighting on 20
Amp circuits, as I think there is some inconsistency present. One advantage I see is that
you can occasionally demand a little more from one of the circuits.

What does that mean? Lighting is pretty much a fixed load. A 15-amp circuit is
sufficient to power 1440 watts of lighting. That's thirty-six 48" fluorescent
tubes. There's _no reason_ to use 12ga wire for a lighting circuit.