Three 4-Way Switches with Central Fan and Individual Lights

Question

I have a situation that I can't find any information for online. A couple quirky things going on that I can't figure out. Unfortunately, I have the switches out and the wires separated.

1. I have three bathrooms each with one multiway switch. Each multiway switch controls a light in that bathroom as well as a central exhaust fan.

2. All of the previous switches were 4-way switches. I know it's possible to use a 4-way as a 3-way but I don't know if it's necessary because of my central fan/individual light situation.

3. There are 4 wires going to the switches in each box, two of them are always hot, one seems to be a common or traveler for the fan, and the last seems to be the common for the bathroom light.

I really hope someone can help explain to me how I should wire my switches!

Answer 1

The fact that you're replacing all of them at once suggests to me that you're doing it for aesthetic reasons.

These switches are not 4-ways - they are a special and rare type called 2-pole or DPST. As such, the "aesthetics" plan probably isn't going to work out - you are unlikely to find a 2-pole in a matching style.

You may be better off changing this over to tandem switches. They are available in a variety of aesthetic forms.

They wire exactly the same as a 2-pole switch, after you take one special step. They ship with one side "ganged" assuming 1 hot wire will supply both devices. You need to follow their instructions to "break off the tab" or separate that side. Failing to do this will probably trip a breaker in your house.

The downside (or upside, depending on how you look at it, is the user is obliged (able) to control fan and light separately.

I personally find "ganged light and fan" to be a grating annoyance: for simple affairs, and personal grooming, I don't need the fan at all. But for more serious affairs, I need the fan much longer than I need the light. Maybe it's just me.

Answer 2

Grab an ohm meter/continuity checker and test those switches. You say they're 4-way .... but suppose instead they may be dual-pole switches. The outward appearance of both types is identical but the electrical function is different. Connect one lead to one of the black-colored screws; connect the other lead to the gold-colored screw on the same side. Confirm continuity between the two terminals -- toggle the switch to its alternate position if necessary.

Next, toggle the switch to interrupt continuity. This next test reveals whether the device is 4-way or dual-pole: check for continuity between the original black-color screw and the gold-color screw on the opposite side. If there's continuity then the device truly is a 4-way switch. If not, then it's actually a dual-pole device.

A dual pole switch is functionally the same as two ordinary isolated ("single-pole") light switches ganged together so that a single toggle operates them both.

It's easy to see how to wire a dual-pole switch to do the function you need. The hot corresponding to the fan circuit goes on one of the black-colored screws; the traveler for the fan goes on the gold-colored screw on the same side. The hot for the light circuit goes on the other black-colored screw on the other side; its corresponding switch leg goes on the gold-colored screw also on that side.