[PLUG-TALK] electrical wiring question

Denis Heidtmann denis.heidtmann at gmail.com
Sat May 28 00:28:57 UTC 2016


(top posting)

I do not have any photos, and the switch box in question is 2000 miles away.
I did not say that there was a cable with 1xBlack and 2xWhite.  I merely
said that I could imagine getting a junction between a white and a black
wire if such existed.  I would be very surprised if such existed.  It would
be the cause of nasty mistakes.

As found this switch was wired as a two-way.  The broken switch was
three-way, but only two terminals had wires on them.  The replacement
switch is a two-way.  And as I said, the house owners said that to their
recollection this switch and light had never been part of a three-way
arrangement.

So I still do not know what arrangement would have a black and white wire
connected together.

I wish we could attach some sketches to these emails.  It would help
clarify the matter.

-Denis

On Fri, May 27, 2016 at 3:22 PM, Pete Lancashire <pete at petelancashire.com>
wrote:

> I'd like to see a photo or two.
>
> And I'd like the see any identification on a the cable with 1xBlack
> and 2xWhite. For residential electrical wire, I'm unaware of any cable
> with two white wires.
>
>
> http://www.how-to-wire-it.com/wiring-a-3-way-switch.html
>
> On Fri, May 27, 2016 at 12:10 PM, Denis Heidtmann
> <denis.heidtmann at gmail.com> wrote:
> > (top posting)
> >
> > If the power feed is at the light and a three-wire cable goes from  the
> > light to the switch and the three-wire cable has black and two whites
> then I
> > understand.  Was such a three-wire cable made?  (I saw no red in the
> switch
> > box.)
> >
> > -Denis
> >
> >
> > On Fri, May 27, 2016 at 11:21 AM, Pete Lancashire <
> pete at petelancashire.com>
> > wrote:
> >>
> >> The wire is sometimes called a traveler. NEC allows this one exception
> >> for wires that are white. It REQUIRES that the wire must be identified
> >> ... tape, permanent marker, paint etc.
> >>
> >> You can not have more then one 'white' traveler.
> >>
> >> Again NEC only allows this for lighting. There are some jurisdictions
> >> that do not allow it.
> >>
> >> Although it is in the Grounding section 200.7 (c) .
> >>
> >> 200.7 Use of Insulation of a White or Gray Color or with Three
> >> Continuous White Stripes
> >> (C) Circuits of 50 Volts or More. The use of insulation that is white
> >> or gray or that has three continuous white stripes for other than a
> >> grounded conductor for circuits of 50 volts or more shall be permitted
> >> only as in (1) and (2).
> >> (1) If part of a cable assembly that has the insulation permanently
> >> reidentified to indicate its use as an ungrounded conductor by marking
> >> tape, painting, or other effective means at its termination and at
> >> each location where the conductor is visible and
> >> accessible............
> >>
> >>
> >>
> >> On Fri, May 27, 2016 at 8:41 AM, John Jason Jordan <johnxj at comcast.net>
> >> wrote:
> >> > On Fri, 27 May 2016 08:03:46 -0700
> >> > Denis Heidtmann <denis.heidtmann at gmail.com> dijo:
> >> >
> >> >>Is  there any legitimate reason to connect a black and white wire
> >> >>together?  I have been trying to conjure some historical reason for
> >> >>this wiring, but cannot.  In hindsight I desperately wish I had spent
> >> >>some time studying the situation.
> >> >
> >> > This happens all the time, especially in switches, and is perfectly
> >> > acceptable. However, electricians normally carry rolls of tape in
> >> > common colors (black, white, red) because it is considered good
> >> > practice to use tape to 'change the color' of a wire inside the box
> >> > just before it connects to the appliance.
> >> >
> >> > The problem is that household wire comes with a black, a white, and a
> >> > bare (earth ground) wire. (If three-conductor wire, the extra hot wire
> >> > is red.) When wiring a switch the black and white wires travel to the
> >> > light, and they are both hot wires, so one should wrap a bit of black
> >> > tape over the white wire to signal to future electricians 'this wire
> is
> >> > white, but it's hot.' Having said that, I think the convention of
> using
> >> > tape to change the color of a wire is recent, because I constantly
> find
> >> > situations in old houses where it was not done.
> >> >
> >> > I should add that it is good practice (although not required) to have
> >> > power in every box, including switch boxes. I always do so because
> then
> >> > I can later (if desired) swap out the switch for a switch+outlet
> >> > appliance. That might explain the wire nuts that you saw in the box.
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