groundwiring
I am replacing two existing 3 way switches. The existing ones did not have a ground attached. The electrical box is plastic. There are ground wires in the back of box that are twisted and crimped together. I am guessing I need to add a pig tail to each of the new switches and connect to existing ground wires. I am trying to figure out the proper way to do this.
Any help would be appreciated.
I think I will have the same issue on a row(4) of light switches.
V/R,
Kevin
What you have is power to the ceiling, and 3-Way switches.
My best guess, is to wire the two blacks together in the ceiling, with a wire nut. One of the whites should be marked. This will go to the Black of the fixture. The other white wire should go to the white of the fixture. And then connect the ground.
So the path will be Panel Hot -> Black wire -> [ Switch Common -> Switch Travellers ->Switch common -> ] WHITE -> Light -> Panel Neutral.
the stuff in Brackets [] is in the wall, and you won't see it.
See this http://diy.blogoverflow.com/2012/01/poles-and-throws/ for more information on 3-way switches.
All the ground wires in a box should be connected together, so add a pigtail from each switch to the ground wire nut, and connect them all together. If this gets to be a lot of wires (sounds like 3 cables and 2 switches, so 5 total) it may be easier to use a push-in connector instead:
or for 6 conductors:
Best Answer
The proper way is indeed to pigtail ground wires from that bundle to each switch. They should be wired in such a way that detaching ground from one switch (to replace it, for example) doesn't impact the grounding of the other switch or anything down the line.
If this makes your bundle of grounds large, you may need to upgrade to a larger wire nut. The wire nut container should have a list of color-coded sizes and the number and gauge of wires it supports.
Side note regarding wire nuts: they should hold every wire very very firmly. Many pro electricians around here note that amateurs don't connect the wire nuts firmly enough and encourage a "yank test": after connecting the wire nut, yank each wire pretty hard. If it comes out, the wire nut isn't connected firmly enough or may be the wrong size.