
How to Install a Trailing Edge Dimmer Switch on a Normal Switch Board
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Trailing edge dimmer switches are designed for modern LED lighting, offering smooth dimming and increased energy efficiency. However, proper installation is crucial for safety and functionality. This guide will walk you through the wiring process and explain the best way to use a dimmer switch to avoid unnecessary power consumption.
Step 1: Gather the Necessary Tools and Materials
Before you begin, ensure you have the following tools and materials:
- A trailing edge dimmer switch (ensure compatibility with your light type)

- A flathead screwdriver
- A Phillips screwdriver
- A voltage tester
- Electrical tape
- Wire strippers
- Wire connectors
Step 2: Turn Off the Power
Safety first—turn off the power at the circuit breaker before starting. Use a voltage tester to confirm there is no power in the switch before proceeding.
Step 3: Remove the Existing Switch
- Remove the faceplate of the existing switch.
- Unscrew the switch from the electrical box and gently pull it out.
- Take note of the wiring configuration before disconnecting the wires.
Step 4: Connect the Trailing Edge Dimmer Switch
- Identify the Wires: Your dimmer switch will have at least two terminals: Live (L) and Load (~). Some models may also include a Neutral (N) and Ground (Earth).
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Connect the Wires:
- Connect the live wire from the wall to the 'L' terminal on the dimmer switch.
- Connect the load wire (going to the light) to the '~' terminal.
- If a ground wire is present, connect it to the ground terminal.
- If the dimmer has a neutral terminal, connect the neutral wire if available.
- Secure the Connections: Use wire connectors to cap the wires and wrap them with electrical tape for safety.
- Carefully push the wires back into the electrical box and secure the dimmer switch with screws.
Step 5: Best Practices for Using a Dimmer Switch
Unlike traditional switches, a dimmer does not completely cut off power when set to 0. It continues to draw a small amount of current, which can reduce its lifespan and consume electricity unnecessarily.
To maximize efficiency and lifespan:
- Pair the dimmer with a normal switch that fully turns off the circuit.
- When not using the lights, switch off the normal switch instead of just dimming to 0.
- Avoid overloading the dimmer by exceeding its rated wattage.
Step 6: Test the Installation
- Restore power at the circuit breaker.
- Test the normal switch to ensure power reaches the dimmer switch.
- Adjust the dimmer to check if the light responds correctly.
- If everything is working properly, install the faceplate.
Final Thoughts
Installing a trailing edge dimmer switch is an effective way to improve lighting control and energy efficiency. However, to ensure proper usage, always turn off the main switch when the lights are not in use rather than just dimming to 0. If you are uncertain about the wiring, consult a qualified electrician.