On Thu, May 27, 2004 at 12:52:41PM -0400, Bob Ammerman wrote:
> The neutral is not available a good percentage of the time at a standard
> single pole switch in a home. In many cases a two-wire (plus safety ground)
> cable brings hot to the switch and switched-hot back to the load.

I don't profess to be an electrician and I don't have a lot of experience.  I
guess it shows. Every box I have in my 30+ YO home has hot, neutral and
safety ground (SG). I'm just trying to envision a wiring diagram where only
hot and switched hot (SH) are available in a box. I guess I can see it: hot,
neutral, and SG come into the light fixture. A separate wire with hot and
SH goes to the switch box. So there's three wires, but no neutral. BTW
how is such a line (especially the white wire) supposed to be marked?

Actually I do have such a problem in my den fan fixture that would be helped
by such a situation. It's a 3way switch wired normally with a neutral going
from the switch to the fixture. It would be better if there was a straight
hot to the fixture so that the fan can be run all the time without being
affected by the switch. In other words there is only a SH at the fixure.  So
if it were layed out where a only a hot/SH went to the switch and there was
always a hot wire in the fixture, I could connect the fan directly to the hot
wire and the fan light to the SH that goes to the switch. I'm a firm believer
that switches should only control lights, not fans. My current thought is
replacing the current 3 wire conductor between the fan box and the switch
with a 4 conductor with both the SH and hot wires heading out to the fan
fixture. But as you (or was it me? ;-) pointed out, hot going directly to the
fan box would be helpful.

So it makes sense, though I don't have it in my own place.

BTW am I right about having to leak current through the load? And what the
heck do you do if the load isn't resistive?

BAJ

>
> > You'll have to leak current through the load like this.
> >
> > Hot -> Control -> X1 -> Switch -> X2 -> Load -> Neutral
> >
> > Where X1 and X2 are connected so that the control and switch can be
> powered
> > through the load even when the switch is disengaged leaking a minimal
> amount
> > of current through the load. You can even use a resistor or cap and a
> zener
> > to limit the voltage and current going around the switch so that the load
> > doesn't get enough power to activate.
> >
> > But again other than the academic exercise, why bother. Connect X1
> directly to
> > the neutral and be done with the task.
> >
> > Or am I missing something significant?
> >
> > BAJ
> >
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