Quick Tip #16 – Three-Way, Two-Way or One-Way Switch?

June 2nd, 2014 by admin Leave a reply »

E036 - Switches - 120 Volt, Single Pole, 3-WayHome systems have some strange terminology. Why are the two light switches that control one light fixture called a three-way switch? You know – the kind with a switch at both the top and the bottom of the stairs. Sometimes it’s up/switch off, and sometimes up/switch on.

The name relates to switching the power line back and forth, and having an extra wire and connector. Electricians call this a three-way switch, and it takes a smart electrician to wire this properly.

You may not care about the details, but you should care about the switches and what they control. Here is the quick tip: You can identify the type of switch by looking at the marking on it.

Single pole switches, with one switch controlling one light, are marked with an “on” and “off ” position.

A three-way switch has no marking because there is no consistent on or off position. The on-off can change depending on the position of the second three-way switch. Take a look at the switches in your home. You may be surprised with what you have overlooked.