Follow these tips and instructions on how to replace or install electric switches, to save you time and effort. Before beginning any electrical repairs, turn off the power at your service panel, fuse box or breaker box. If you know which fuse or breaker controls the circuit you will be working on, remove that fuse or trip that breaker. If there is any doubt, you can remove the main fuse or trip the main breaker.

Caution: Tripping the main breaker or removing the main fuse will usually shut off all power to the house. Take the time to read the directions thoroughly to help ensure a satisfactory job.


Toggle Switch
The popular toggle switch has an arrow-shaped armature that floats between the contact points when the switch is in the off position (A, Fig. 1). This armature comes in contact with both terminals when the switch is flipped to the on position (B), thus providing a continuous flow of electrical current to the light or appliance.

Mercury Switch
The mercury switch has a small hollow cylinder, partially filled with mercury (Fig. 2). In the off position, the small contact point is above the mercury level (A). When flipped to the on position, the contact point is immersed in mercury (B). This establishes contact between the two terminals and provides power to the light or appliance.

Silent Switch
The silent switch has a steel spring armature that is pressed away from the bottom terminal when the switch is turned off (A, Fig. 3). Flipping the switch lever to the on position moves the steel spring back against the contact point (B), thus establishing contact in the circuit.

For installation purposes, all three types of switches can be used interchangeably.

Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the National Retail Hardware Association. Every effort has been made to ensure accuracy and safety. Neither the NRHA nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.