basic home wiring question

I know, aren't they all? 8^D
Anyway, I have a couple of related questions:

1) When referring to a home wiring scheme or type of switch, does the term "single pole" refer to a circuit or device designed with or designed to work with just one switch?

2) Conversely, does "3-way" refer to those circuits/devices with/for multiple switches?

I ask because I have a 120v circuit with 3 switches - one of those being a dimmer - controlling a light fixture. In order to turn the light off when using one of the non-dimmer switches, the switch must be positioned so the blade is midway between off and on. In other words, if "on" is 11 o'clock and "off" is 7 o'clock, my switch must be positioned at 9 o'clock to turn the light off. Both the 11 o'clock and 7 o'clock positions cause the fixture to illuminate.

Would this be caused by a single-pole dimmer being used where a "3-way" (?) dimmer should have been installed, or do I have other issues? The dimmer in question has just two leads coming from it.

TIA,

dave woodall

 

The number of poles on a switch refers to the number of circuits it can interrupt. For example a single pole switch can interrupt a single 120V circuit (one hot wire). A double pole switch can interrupt a 240V circuit (2 hot wires). A three way switch has three voltage terminals on it. A common and two travelers. Think of it as a Y where the common is connected to the leg of the Y and the travelers are connected to the two arms of the Y. The switch will connect the common to one arm in the down position and the other arm in the up position. With two three way switches, you can control a light from two separate locations. You state that you have three switches. If all three can control the light, then one of them (the middle switch in the circuit) is a 4 way switch. It has 4 voltage terminals 2 in and 2 out. This switch connects the in to the out either straight through or cris-crossed, depending on the switch position. Yes, a three way dimmer will probably be called for.

 

Thanks Scott. By mentioning the 4-way switch, you actually answered another question of mine that I really didn't know how to phrase concisely earlier.

reagrds,

dave woodall