> >
>

# 3 way switch used on a two way circuit?

#1
09-22-13, 11:42 AM
Member
Join Date: Sep 2013
Location: USA
Posts: 6,138
3 way switch used on a two way circuit?

Can a 3 way dimmer switch be used on a two way light circuit? If so I just don't need to connect the red wire?

#2
09-22-13, 11:47 AM
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 46,232
Give it a try. You won't hurt it. Not all dimmers work like that.

#3
09-22-13, 12:37 PM
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,058
Terminology note: No two way switches in the U.S. That is the British term for a three way switch. Usually what you are referring to is called a regular switch but that is rather imprecise so I usually call it a single location switch or SPST switch. Even more trivia: A three way switch is SPDT switch.

SPST=Single Pole Single Throw
SPDT=Single Pole Double Throw

#4
09-22-13, 01:04 PM
Member
Join Date: Sep 2013
Location: USA
Posts: 6,138
Hmm...

We normally refer to a two way switch as having one light and one controlling switch. Hence a two way.

One light controlled by two switches we term as a three way switch or circuit. I've been taught to include the light as a "switch" or one of the elements be it two, three or four.

#5
09-22-13, 01:23 PM
Member
Join Date: Jan 2010
Location: USA
Posts: 9,397
We normally refer to a two way switch as having one light and one controlling switch. Hence a two way.
I have never heard that.

I've been taught to include the light as a "switch" or one of the elements be it two, three or four.
What if you have 4 switches and 1 light, what would you call that?

#6
09-22-13, 02:33 PM
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,058
The British are most correct. There are two ways to control the light, one way at each switch. We may say three way because there are three ways the switches can be set, Both up, both down, one up, one down. Oddly Wikipedia claims a SPST switch is a two way switch but many of their articles seem to be written by non Americans. For instance try looking up GFCI and you are directed to the European term RCD. Best to just say SPST for a single location switch and no confusion. Note I have heard some here call a single location switch a single pole switch to differentiate it from a 3-way but a 3-way is also a single pole switch. Now back to our regularly scheduled program.

If so I just don't need to connect the red wire?
That is the way it is usually done but it could vary with manufacturer as written earlier by PJ.

#7
09-23-13, 05:20 AM
Member
Join Date: Mar 2010
Location: USA
Posts: 3,100
A 3 way dimmer kit will work fine on a regular single switch location light circuit. Just don't use the remote switch module.

Of course you don't want to use a 3 way kit for this prupose because a single pole dimmer swiitch costs less.

(extraneouls information) More ambiguity on the subject of 3 way circuits. Some 3 way dimmer kits refer to the two modules as "master" and "slave". IMHO the main dimmer module should really be called the slave because it takes orders from the other (remote) module.

#8
09-23-13, 02:20 PM
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
More ambiguity on the subject of 3 way circuits. Some 3 way dimmer kits refer to the two modules as "master" and "slave". IMHO the main dimmer module should really be called the slave because it takes orders from the other (remote) module.
Allen, if you're saying that the "master" and "slave" labels might make sense because only one of the units can control the lights while the other(s) can tell that one what to do, but that it would make more sense if the one(s) issuing commands was/were called "master" and the one taking orders was called "slave," I concur wholeheartedly.

Drives me slightly nutz when they label them the other way around.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off