[Novalug] OT: Electrical Wiring Q
Mon Aug 29 19:20:48 EDT 2011
The fourth wire is for a 3-way switch, for lights that are controlled from more than one switch. The way a 3-way switch generally works is that power comes into one switch, goes through one of the two "travelers" and comes out the other switch and into the fixture. The switch itself rather than disconnecting the power just alternates which traveler it is connected to. If both switches are connected to the same traveler then the circuit is complete and the light is on. If the switches are on the opposite travelers then the circuit isn't complete and the light is off.
----- Original Message -----
From: Nino R. Pereira [mailto:email@example.com]
Sent: Monday, August 29, 2011 02:25 PM
To: firstname.lastname@example.org <email@example.com>
Subject: Re: [Novalug] OT: Electrical Wiring Q
Now, you don't say explicitly but we assumed that the original light has
a white and
a black wire that connects at the switch straight through to the house
The third wire is then green, and ground. So, what's the 4-th wire for?
Normally, white is power, black is neutral, green is ground. What's the
Also, check that the total power from the two light passing through the
is below its rating. Both lights are fluorescent bulbs, right? or at
incandescents, and not 500 W halogens? And it's not a dimmer switch? those
may not be able to handle the increased current.
On 08/29/2011 09:50 AM, Daniel Copeland wrote:
> Wire the new light in parallel with the existing lights, matching
> black to black and white to white. You may be able to stack them into
> the same terminal on the switch, or make an extension and use wire
> nuts to tie them into the same terminals.
> On Mon, Aug 29, 2011 at 9:29 AM, greg pryzby <firstname.lastname@example.org
> <mailto:email@example.com>> wrote:
> Looking for electrical wiring help.
> I have 3 light switches (2 have 3-wires and 1 has 4-wires). I put a
> new light in near the 4-wire switch.
> I would like to tie the new light (2-wires + ground) into the wiring
> at the 4-wire switch. I can't get it to work/cycle w/ the lights.
> Meaning when the existing lights are on, the new light is out. When
> the new light is on, the existing lights are out. Playing with the 3
> switches I can get the new and existing lights all out, but nothing
> gets them all on.
> ANY constructive help (besides hire an electrician) are welcome. I
> imagine the internet can save me the electrician fee and teach me
> about wiring.
> greg pryzby greg at pryzby dot org
> WEB: http://www.RestonArtisTree.com/
> TWTR: gpryzby
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