How to connect a Double Pole Switch?

[Homer]

I am changing my light switches around the house from old fashion rusty ones to new ones. Yesterday I took off one of those switches and I realized that is a Double-Pole Switch and what is does is basically turning two lights in my hallway on and off. I went to home depot to get a new switch but they didn't have it so I decided to put the old one back but I can't remember how those wires were connected. I have two pairs of wires (black and white). On one pair (Pair A) my tester shows they are both Hot (both black and white wires). When I check it with Voltmeter, only Black one shows Hot (it's 110v). The other one (white) doesn't show anything. The other pair (Pair B) doesn't show anything.

Also there is another Switch for switching the same light as the end of hallway (Three-way Switch). I believe the other pair of wires (Pair B) is connected to Three-Way switch.

If I connect a light ball to Hot Wire from Pair A and one from the Pair B, light ball goes On. If I switch the three-way switch and do the same thing with another wire from Pair B, light ball goes On too. Something like this?:

H o o-------------o \\o-----N o o-------------o A B

If I check voltage of Hot wire from Pair A with another Hot from another switch box I will get 220v. I have no idea why I should have two phases inside my house (they should be all 110v).

Please help me fugure this out.

Thanks,

Homer

[Bill]

How many switches are for this same light?

There is a "double pole switch" and then there is a "four way switch"

These are different.

If there are 3 or more switches for the same thing, then probably a four way switch. Below is a diagram.

4 way... Double pole... (See A DOUBLE KNIFE SWITCH)

[Bill]

How many switches are for this same light?

There is a "double pole switch" and then there is a "four way switch"

These are different.

If there are 3 or more switches for the same thing, then probably a four way switch. Below is a diagram.

4 way... Double pole... (See A DOUBLE KNIFE SWITCH)

[Homer]

SWITCH)

Two Switches.

This switch is Double-Pole. On its back it says Two Input and Two Output (It's two single switches in one box).

[Doug Miller]

There are several types of double-pole switches. How many screw terminals does yours have?

You've probably figured this out already... but next time, sketch out which wires are connected to which poles on the switch before you disconnect anything.

Voltmeter is probably correct.

As expected.

Is there only *one* other switch (two total) controlling the same light?

Probably -- does flipping that switch change the voltage readings on either wire in Pair B?

Do you mean light *bulb* ??

What happens when you flip the 3-way switch? Does it go off?

What happens when you flip the 3-way switch again? Does it go off?

It better *not* be -- switches should *never* be placed on the neutral side of a circuit.

Why are you doing that? What do you expect to measure?

That is incorrect -- nearly all North American homes have 240V service. There are two separate hot legs, each at a potential of 120V with respect to neutral, and at a potential of 240V with respect to each other. You're measuring from one hot leg to the other, and seeing exactly what you should see when you do that -- but why are you doing that?

[Doug Miller]

So there are actualy two separate switch levers? How many screw terminals total?

Can you post a photo of the switch somewhere?

[Homer]

What I have is a DPST (Four Screws, Two marked as Input, Two as Output).

[Homer]

- Shouldn't be two hot legs in fuse box and only one circling around the house (the other one goes to Oven and other 240V appliances). Am I wrong?

- I only have two switches for those two lights in my hall way.

- Flipping the other switch does not change the voltage readings on either wire in Pair B. But it makes them (one at the time) neutral. If I connect a light Bulb to any one from Pair B and Hot one from Pair A, I can turn the light on/off by flipping the other switch.

[Bill]

The only time I would use a double pole switch is with 240 volts. Like a range or hot water heater would use. But I would not need to place a switch on these. Of course there are saws and shop equipment which are 240 volts and it would be normal to place a switch going to the outlets for these.

So I'm trying to figure out why a double pole switch would be installed to switch a 120 V light?

Note you can use a continuity tester to be sure the switch is actually a double pole and not a 4 way. That might help.

Double pole = Off, neither input connects to either output.

4 way = Flipped either way (no off/on marking), one input connects to one output, flip switch and connects to other output.

[Bill]

P.S. Keep in mind if old house, people remodel these. There may have at one time been 3 switches controlling the light. Then remodel and they just tied wires together and hid in wall.

Or homeowner handiwork. No telling what they may have done!

Or at one time there may have been a large load which required two separate circuits on one switch. Then later remodeled and made the switch control a light instead????

All sorts of possibilities...

[Homer]

Tested already. It's Double Pole. Two screws marked as Inputs and two as Outputs. Inputs are not connected to each other or outputs if I flip the switch off. If I flip it On, one Input is connected to one Output and another Input is connected to the other Output.

[Doug Miller]

Pretty hard to see how that could have ever functioned as a three-way switch.

I can believe that this one functions as a master switch:

- if it's off, the lights are off regardless of the position of the other switch

- it it's on, the lights are controlled by the other switch

[Charlesmurphy via HomeKB.com]

Yes, you are wrong. One phase does not circle the house. It sounds as if you need an electrician.

[Doug Miller]

Yes, you're wrong.

Time to call a pro.

[Jeff Wisnia]

Homer, might your last name be Simpsos?

Your utterances on this thread represent an exellent example of what the legal profession uses, ie language which tends to supress information.

How about telling us what kind of "tester" you're using and what you are connecting its leads to when you get those indications.

Again, what kind of voltmeter, electromechanical movement or digital? And what are you connecting its leads to when you make those measurements?

When measured in reference to what? each other, neutral, ground or your gonads?

Do you understand how capacitive coupling of AC signals can cause "phantom voltages" to be measured by sensitive intruments. (Actually, "phantom" isn't really a good descriptive term, there IS a voltage present which does get measured, there just isn't more than a few hundred microamps of current delivering capability there, which for practical purposes might as well be zero.)

I knew we'd eventually get back to your gonads.

******

Lim time again:

There once was a man from Woonsocket, Who stuck his big dick in a socket. His wife was a bitch, And flipped on the switch, And his balls both took off like a rocket.

******

I'm really having a hard time figuring out how a DPST switch in the original location could be wired to make a "three way" circuit work right,

Do you have the knowledge and ability to use the ohmmeter function on a meter to measure what that switch does when it's disconnected from all wiring? If so, do so. I'm betting you'll find it is really a SPDT, with maybe the fourth terminal for "ground".

Getting serious, I think you'll just need to replace that old switch with a SPDT ("three way") switch with the hot wire from Pair A connected to the "arm" terminal and the two wires from pair B connected to the two "contact" teminals. As far as the second wire in Pair A goes, you can probably cap it off and leave it unconnected.

My advice is warranted for exactly what you're paying for it, as I'm not there to verify what you've explained thus far, and have no way of knowing whether for example the "second wire in Pair A" might actually be a ground lead.

HTH,

Jeff

[John Cochran]

What you're describing doesn't conflict with your having a 4-way switch. In fact, seeing the connections labeled as "Input" and "Output" argues very strongly for your switch being a 4-way switch.

See about getting a ohm meter or a continuity checker. If you can't do this, just use a flashlight bulb, a couple of batteries, and some tape and wire.

Test the switch you have using the continuity checker. Assuming it's a

4-way switch you should see the following behaivor.

Switch set one way Input 1 connected to Output 1 Input 2 connected to Output 2

Flipping the switch you'll get Input 1 connected to Output 2 Input 2 connected to Output 1

If upon testing the switch you determine that it is a 4-way switch, then take a look at

and see if it helps you understand how a 4-way switch is connected and helps you with your problem.

[John Gilmer]

OK.

It "sounds like" you have a 4-way switch that wasn't wired properly in the first place.

"Proper" in this context means that you have the "return" of a circuit that's not in the same cable or conduit as the supply.

When you wire 3-way or 4-way switces with "romex" you MUST use 3 wire (or more) cable. (That's RED, BLACK, and WHITE.)

In a switch loop to a three way switch, the white wire is HOT all the time and the 3-way switch connects the white wire to either the red or the black wire.

If you have two (or more) switches controlling the same fixture and there aren't any RED wires in the junction boxes the guy who wired it was too lazy to get the proper 3 conductor cable.

[Homer]

Thanks John. I will test it when I get home. From what you've described, it maybe 4-way. This is what I tested:

Switch set one way Input 1 connected to Output 1 Input 2 connected to Output 2

Flipping the switch you'll get Input 1 is not connected to Output 1 Input 2 is not connected to Output 2

If it's a 4-way, how can I replacing it with 3-way switch? Assuming we only have two switches now.

Homer

[Joseph Meehan]

..

After reading through this thread, I also suggest bringing in a professional. What we are seeing is an homeowner, who while intelligent is not well informed or experienced about residential electrical systems and is not confronted by a not so common wiring situation that the average homeowner would have very little or no experience or knowledge of. It is also a little too iffy for anyone who can't really see everything to makes sure they have covered all the possible situations you might confront and therefore you could be facing a serious hazard. Time to call the professional in.

[Mark Lloyd]

Controlling lights on 2 different circuits?