On 3/14/2010 2:34 PM, Bill wrote:
Thank you for the lessons in electricity! I take it I should be installing
"4-wire" outlets if I'm
planning to purchase new 220v tools from Delta or Grizzly, correct?

Nope ... most 220/240v woodworking tools in North America only need a
total of 3 wires to both work properly and comply with code.

The three wires needed for 220/240v operation a Two hot wires (one
from each hot leg of the service/sub panel), and one ground wire. The
ground wire, while not necessary to power the equipment, is necessary
for safety and code compliance.

The "four wire" cables/installations you mentioned are used for 220/240v
appliances (like stoves and dryers) that are also equipped with timers,
lights, etc, and that operate on 120v.

That said, there might be the ocassional woodworking tool that requires
120v also for lights and/or speed control circuits, etc ... so do your
homework before attempting to wire.

If you have one of these 4 wire circuits and don't need the extra wire,
then simply use the two hots wires, usually black and red (which
can/should be verified at the c'bkr) and the ground wire; and put a wire
nut/tape on the end of the neutral/white wire in the receptacle.

NOTE: some 220/240v circuits use "2 wire w/ground".

In this case the white, neutral, wire can be used as one of the two
necessary hot wires but it must be clearly marked on both ends, at the
c'bkr and the receptacle (generally with a wrap of black tape), so that
those coming after you know it is indeed being used as as a "hot" wire.

I probably should examine a book (on setting up/modifying new existing
lines). Any suggestions regarding a book? I recall seeing a few books on
wiring at the BORGs.

Most of those are well worth the price paid for a DIY'er. Don't confuse
yourself with learning about 3 phase power unless you have a need; take
your time, understand and think about what you're doing and don't do it
until you do ... it is not a bad idea for a home/shop owner to turn off
the power to the ENTIRE structure when doing electrical work (and if you
can lock up the service panel so that only you have access while doing
the work, so much the better).

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Last update: 10/22/08
KarlC@ (the obvious)