[PLUG-TALK] electrical wiring question

John Jason Jordan johnxj at comcast.net
Fri May 27 15:41:10 UTC 2016


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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