How To Wire 3 Switches With One Power Source Today, we’re going to walk through how to wire multiple light fixtures using just one power feed—specifically when you have three separate switch boxes controlling different lights.
Understanding the Setup
Behind me, we have a three-gang switch box. Let me flip the camera around so you can get a better look.
This single switch box controls:
- Outdoor lights
- Entryway pot lights
- A light by the fireplace
The issue we encountered was that the fireplace light was on all the time. That signaled a problem—likely a wire that’s directly connected to the feed and bypassing the switch. We’ll need to correct that and also install a double sideways switch to accommodate the configuration.
Wiring Basics: One Feed, Multiple Switches
In this setup, we have one main power feed coming in from the electrical panel. Here’s how everything is connected:
- Black (Hot) Wires: All black wires are bundled together. One of these is the main hot feed, and pigtails branch off from it to supply each switch.
- White (Neutral) Wires: All the white neutrals are bundled together and run to their respective light fixtures.
- Switch Wiring: From each switch, a wire runs to control a specific light or group of lights.
This method allows us to control multiple lights from one power source, but it’s important to wire everything correctly within the box.
Important Considerations for Light Loads
When using a single circuit to power multiple lights, there are some limits to keep in mind:
- General Rule: You can run a maximum of 12 light fixtures per circuit—unless the lights are specifically low-load, like pot lights.
- Pot Lights (LED): If you’re using LED pot lights at 7 watts each, you can add more—as long as the total load doesn’t exceed 80% of your circuit’s 15-amp capacity (which is 1500 watts). That’s about 1,200 watts usable.
- Unknown Loads: It’s safer to limit yourself to 12 fixtures per circuit because you don’t always know what kind of fixtures will be installed later. Someone could add a high-wattage chandelier or other heavy load.
Always plan your circuits with potential future usage in mind.
Wrapping It Up
We’ve completed all the proper connections in our box, and we’ve ensured the wiring is safe and up to code. As a reminder, understanding load distribution on a circuit is critical, especially when dealing with lighting.
We hope you found this helpful! If you did, don’t forget to like and subscribe, and we’ll see you in the next video.
