"Terry" wrote in message
...
On Wed, 26 Mar 2008 21:06:36 -0400, "Bill Stock"
wrote:


"Nate Nagel" wrote in message
...
Bill Stock wrote:
"RBM" wrote in message
...

"Bill Stock" wrote in message
M-Free...

Old question,m I'm finally getting around to:

OK, I have two lights, two switches, both lights are on the same fuse.
It looks like both junction boxes have other circuits running off
them,
which I think is the same fuse.

Plan is to run three way wire between the two lights white/red to
socket, blacks connected. Then run two way wire to the 1st switch
white
(black tape) to red (socket) black to black. Then run three way wire
bewtween the two 3 way switches (white wire taped).

But I'm not sure if it matters which socket I run the switch to, since
they both have other circuits running off them. Can't I just run my
other circuits off the black/white in either junction box as it is
now?
This is where it gets a little confusing.

TIA

Leave all the existing wiring the way it is. Run three wires between
the
two switches. At one switch location disconnect and tape the existing
wires that were on the switch. Disconnect and tape the two wires that
were on that switch's light. At the first switch location you can
remove
the existing single pole switch and now wire both three way switches to
control that one light. Last, you need to run a two wire cable from one
light to the second


OK, this is the same as the end run wiring diagrams I've seen. This
makes
sense, since you're switching the circuit as opposed to the individual
lights. The problem is that I don't have access to the wiring and I
would
have to drill about 10 joists to use your method. I was hoping to use
the
existing two wire cable between the lights to pull the new 3 wire cable
between the lights. So is there some reason I can't use the original
method other than it simply won't work?

Thanks.


1) assuming the original install was to code, the cable will be stapled
at
each box, and if the run is lengthwise to the joists, at probably a
couple
locations in between.

2) I don't feel ambitious enough to completely think it through, but
keep
in mind that you need to maintain zero net current through all cable
assemblies (that is, all currents within a cable assembly need to sum to
zero, considering "hot" to be positive and "neutral" to be negative.)
Or
in other words, you can't have a feed coming from one assembly and get
your neutral from another. I can't say for sure whether that is what
you'd end up with with your plan, but think about it.

nate

Thanks, I've seen lots of three way wiring diagrams done like this, but of
course they don't show any other circuits in the box. I don't think there
are any (if any) staples on the wire I want to pull. I took pictures when
the ceiling was down for renovations. As for being to code, these guys did
not pigtail any of the Al to Cu connections and it passed inspection.

I know what you mean about the three way wiring, that's why I was hoping
someone could save me the brain work. I'd like it to work AND be safe.


What you need make sure before you can plan the route is that the
existing wiring has to have a hot and a neutral at each box so
everything stays hot.

Then, because the you are switching both lights from the switching
combo you have to have a red wire connected to the black wire of each
light.

So you have to have a black, white, and red between the boxes before
you do any switching. The black will be hot all the time (and keep
everthing working) The white will supply the light at both boxes (and
keep everything existing working). Then the red will be used to
switch on and off.

If the electrician installed the cable properly, the existing wire
will be stapled to the studs.

Here is a crude drawing of what you are shooting for.

http://i27.tinypic.com/sg2uzd.png


Thanks Terry,

I'll have something like Option 6 provided by RLM:

http://www.homeimprovementweb.com/in...ch-option6.htm

Except that I'll have additional circuits feeding out of the black and white
in each light box.