"Steve McDonald" writes:


So if I connect the white wire from the new outlet to the 220V outlet's
centre pin (neutral), this will essentially put the white wire on the saw's
frame?

Note that line voltage in a residential setting varies between 110 and
120 plus or minus 5% or so. I'll use 240 and 120 in this article.

Generally tablesaws are not wired with a neutral at all. For what you
want to work safely, your 240 outlet must be wired with four (4)
wires - two current carrying conductors (typically red and black), one
grounded conductor (typically white) and one grounding conductor (typically
green or uninsulated). Note that when romex XX-2 with ground cable is
used for 240 three-wire outlets, the NEC allows the white conductor to be used
as a current carrying conductor (although it should have been permanently
marked with black tape or other black marking at both ends). Be very
careful not to assume that this white conductor is a grounded conductor,
you cannot make 120 from this configuration safely (simple check, use
an DVM set to AC 600V to measure the potential difference between
the two conductors - it should be either 120 or 240).

A 120 outlet will need three conductors. One current carrying
conductor (typically black), one grounded conductor (typically white)
and a grounding conductor (typically uninsulated). If your 240/220
volt outlet doesn't have a grounded conductor (which is what I expect
you'll find, if the outlet was run specifically for the tablesaw),
you _cannot_ safely tap a 120 volt circuit from it.

Note the NEC refers to the neutral conductor as a ground_ed_ conductor
and the ground wire as a ground_ing_ conductor.

The grounded conductor and grounding conductors may only be connected
together at a single location, and that single location _must_ be the
service entrance (this is to prevent inadvertent current flows in the
grounding conductor that can cause appliance metal frames to become
energized).

If your receptacle is installed in a metal box, the box must be bonded
to the grounding conductor.

I would recommend that you have an electrician evaluate your setup if you
are unclear on what to do.

scott