LED Bulbs and Photocells – Compatability Guide

As an electrician, I have installed hundreds of photocells and whilst the technology may be a little old school now there is still a lot of merit in using them. They are a robust, cost-effective way of controlling lighting that once installed requires little maintenance.

Photocells have been around for ages but as LED lights are now the norm we need to know if LED bulbs will work with photocells. Fear not, this quick post has the answer!

Exterior LED wall lights are often controlled by a photocell.
Exterior LED wall lights are often controlled by a photocell.

LED bulbs will absolutely work with photocells. The photocell is placed in the circuit and automatically controls the switching, so the type of bulb or light fitting used has little effect. However, there are a couple of checks to carry out.

LED lights are now the norm and as such photocells that can control LED lights are also the norm, but we need to check a few factors to make sure. An incompatible photocell and light will either not work, cause the light to flicker or damage the photocell.

LED Bulbs Will Work with Photocells

The photocell is positioned in the control circuit of the light. A standard switch opens and closes to either allow current to flow to the light or to prevent it. A photocell is simply an automatic switch operating in the same way but triggered by light levels.

As the photocell sits in the circuit as a switch, assuming that the LED light bulb is compatible with the type of light fitting it is going into there shouldn’t be a problem providing the basics are checked which are covered below.

I’ll point out quickly that I would always recommend having an override switch so that the light can be easily turned off, rather than just relying on the photocell. This is especially important if we don’t want the light to stay on all night, we need another way of controlling it.

Compatibility of Photocells and LED Bulb Considerations

A few checks of the product specification and the intended use, before we start, can save a lot of hassle. I have definitely been caught out in the past by assuming a product does what I want only to read the product spec after installation and find out I have made a big error!

Learn from my mistakes and check the 4 considerations below before purchasing to make sure your photocell and LED light are compatible and to save another trip in the car back to the shops

Voltage Rating

We need to double-check that the voltage rating of the photocell matches up with the voltage rating of the LED light you are trying to control.

As an example, you may have lights in a campervan that are 12V DC. A mains-powered 230V AC photocell is not going to be compatible. Whilst it may sound a little tricky, the specification on the light and photocell will tell you its voltage operating range.

Outside lighting on photocells can give an amazing design aesthetic

Dimming Capabilities

Some photocells have the option of dimming the lights down, often called daylight saving. This is a really cool energy-saving feature and something we should explore further at some point but for now, we’ll stick with the basic premise that as more daylight is sensed, the photocell dims the lights to lower levels to save energy.

If you go with a dimming photocell, you’ll need to ensure that the LED bulb chosen is capable of being dimmed (like these from Amazon). This is not a given and something that should be checked. On a side note, this is the same as when using standard dimming switches with LEDs – they need to be compatible.

Confirm it’s a Modern Photocell

LEDs are the norm now when it comes to new installations so I would expect the vast majority of photocells sold through standard channels to be compatible with LEDs but worth looking at the spec just to double-check.

Older photocells will only work with older style lamps, such as tungsten, but as mentioned all manufacturers understand that LEDs are the go-to install option now

Ensure the Power Rating is Sufficient

Photocells will have information regarding the load rating they can safely switch. When we talk about load rating we essentially mean how many lights (and how powerful the lights are) that can safely be switched.

For example, if the circuit load for the LED lights is 4amps and we have a photocell that can only switch 2 amps it is not going to be compatible.

In most domestic settings only one or two lights are being controlled, but this rating is a serious consideration when it comes to commercial lighting design. FYI – we often get around the problem by using a contactor alongside the photocell.

Can You Put a Photocell on Any Light?

So long as the light and photocell are compatible (using the checks above) a photocell can be put on any light. Typically, we use photocells on exterior lights, so motion sensor lighting may be a better option to investigate first.

Hire a Local Electrician

I would always advise hiring a local electrician to carry out any electrical work and installing a photocell is no exception. They will have the specific tools and knowledge to make the job go smoothly and easily, saving hours of shopping around, trips out in the car and the potential dangers associated with electricity.

Dave Nicholas

I have worked as a professional electrician for many years and like to use my experience to help others in any little way I can.

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