What is 3-way wiring?

[foolios]

I took a picture of the wiring to a wall switch because it has 4 connections onto it rather than 3. I did a switch previously in the house that only had a ground and two wires. This switch has a ground, two wires, plus this extra wire that goes from this switch to another switch just next to it in the same box.

I was wanting to replace this switch with a single pole dimmer. This is when I discovered this odd wiring pattern. I figured I could just remove the wire that goes between switches from the equation but the dimmer will not work.

I noticed that the box did say that a 3-way system will need a 3-way dimmer. But it also mentions how to make the 3-way wiring work with the single-pole by removing the ground. Well, whatever that's all about will not work because their diagram does not match the dimmer switch at all...

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1) Ok, so what is this extra wire between switches all about?

2) Why couldn't I get the dimmer to work with the wiring in this box?

Thanks in advance.

 

[a1]

Welcome back foo,

It a long time no speak.

If it is a three way - then it is likely to be an Intermediate Swith - You are in the US od A, Yes?

If you mean a 3 Gang, then it is likely to be a strapper/perm live feed to next light switch.

But - See what the other guys say.

 

[patspark]

sounds like an intermediate switch can we see the picture you took

ok i can see the picture now not very clear

the cable that connects the two swiches is that in the same

teminal as one of the other cables

if so it just a live link

so should be a like for like swop for your dimmer

if you are in the states do the do a dimmer for that grid

 

[Apache]

Is this any help?

https://www.youtube.com/embed/yxRmbi6uuzk?feature=oembedIt's American

 

[Apache]

Do they not sheath the earth in the US?

 

[foolios]

I don't see grounds sheathed too often in house wiring. At the box anyhows.

Ok, now I'm wondering why this would be set up like this for this lighting. I don't know of any other switches that control any other devices. Stumps me...

I will watch the video, thanks for the link.

 

[patspark]

i like the dog cock connectors on the white in the switch

aint seen them used for years

 

[foolios]

Ok, so this extra wire in the back of that switch; the one at the bottom that's grey but doesn't have a black/red tape on it is a jumper. It goes from that switch to the other switch in the same box.

I guess what happened is that they only ran one set of hot/neutral through the wall to these two switches and the jumper is used to power the second switch/light.

I think that's what might be happening unless someone can correct me.

 

[Apache]

The picture is difficult to make out, but does the screw that the grey cable is attached to hold the cable with the black tape in position? What I mean is are they actually joined together?

 

[Theorysparky]

foo

look at this site

http://www.electrical-online.com/extra-graphics/3wayswitch.htm

it may help

 

[foolios]

The picture is difficult to make out, but does the screw that the grey cable is attached to hold the cable with the black tape in position? What I mean is are they actually joined together?

Nope, the cable with the black tape on it is going into a hole in the back of the switch. What I believe is happening is that these two wires are sharing a hot connection. The one on the screw is a jumper from the other switch carrying current to this switch. Then the grey that is in the hole in the back must be going to the light, providing it with power. Then after the light the wire with the red tape must be the return to the switch from the light.

I ended up braving it and hooking all the wiring together the way I think it should go. The dimmer works. I had to wire cap together the jumper and wire to the light together to get the dimmer to work.

Here is a picture of this odd wiring mess:

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[daryl631]

Can you imagine nic passing wiring like that on on the video on annual inspection