12v Photocell Wiring Diagram – Your Ultimate Guide

If you’re looking to install a photocell in your outdoor lighting system, you’ve come to the right place. Photocells are a great way to conserve energy by automatically turning your lights on and off according to the amount of natural light available. In this article, we’ll discuss the basics of 12v photocell wiring and provide a step-by-step guide on how to install one in your lighting system.

What is a Photocell?

A photocell, also known as a photoresistor or light-dependent resistor (LDR), is a type of resistor that changes its resistance according to the amount of light that falls on it. When the light level drops below a certain threshold, the resistance of the photocell increases, causing it to switch on an electronic circuit. Conversely, when the light level rises above a certain threshold, the resistance of the photocell decreases, causing it to switch off the circuit. Photocells are commonly used in outdoor lighting systems to automatically turn lights on at dusk and off at dawn, or to turn on lights when motion is detected.

Why Use a 12v Photocell?

There are several reasons why you might want to use a 12v photocell in your lighting system:

  • Energy Efficiency: Photocells help save energy by automatically turning off lights during the day when they’re not needed.
  • Convenience: With a photocell, you don’t have to worry about manually turning your lights on and off every day.
  • Safety: Outdoor lighting can improve safety by illuminating walkways, driveways, and other areas that might be hazardous in the dark.
  • Security: A well-lit property can deter burglars and other intruders from entering your home.

How to Wire a 12v Photocell

Wiring a 12v photocell is a fairly simple process, but it’s important to do it correctly to ensure that your lighting system works properly. Here’s a step-by-step guide to wiring a 12v photocell:

Step 1: Choose the Right Photocell

The first step in wiring a 12v photocell is to choose the right one for your lighting system. Photocells come in various shapes and sizes, so be sure to choose one that matches the specifications of your lighting system.

Step 2: Gather Your Tools

Before you start wiring your photocell, you’ll need a few tools, including wire cutters, wire strippers, pliers, and a screwdriver. Make sure you have everything you need before you start.

Step 3: Turn Off the Power

Before you start working on your lighting system, be sure to turn off the power at the circuit breaker to avoid any accidents or injuries.

Step 4: Connect the Wires

Connect the wires from the photocell to the power source and the lighting fixture according to the wiring diagram that came with your photocell. It’s important to connect the wires correctly to avoid damaging your lighting system.

Step 5: Test Your System

Once you’ve connected the wires, turn the power back on and test your lighting system to make sure everything is working properly. If your lights don’t turn on or off at the right time, double-check your wiring to make sure everything is connected correctly.


What is the Difference Between a Photocell and a Timer?

A photocell uses natural light to turn your lights on and off, while a timer uses a set schedule to turn your lights on and off. Photocells are more energy-efficient because they only turn your lights on when they’re needed, while timers can waste energy by keeping your lights on when they’re not needed.

Can I Install a Photocell in an Existing Lighting System?

Yes, you can. Installing a photocell in an existing lighting system is a great way to save energy and improve the functionality of your lights. However, it’s important to make sure that your existing system is compatible with a photocell before you install one.

What Do I Do If My Photocell Isn’t Working?

If your photocell isn’t working, there are a few things you can try. First, make sure that your wiring is correct and that your power source is working properly. If everything looks good, try cleaning the photocell lens with a soft cloth to remove any dirt or debris. If your photocell still isn’t working, you may need to replace it with a new one.


Wiring a 12v photocell is a simple and effective way to improve the functionality of your outdoor lighting system. By using a photocell, you can save energy, improve safety and security, and make your life a little bit easier. If you’re not comfortable doing electrical work yourself, be sure to hire a professional to help you install your photocell. With a little bit of effort, you can enjoy all the benefits of a 12v photocell in your lighting system.