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How Does Emergency Lighting Work?

If you’re running a commercial building then having emergency lighting is not only of the utmost importance; it’s required by law. For anyone that’s just getting started, there may be a lot of questions and one of the questions I get asked most frequently is how does emergency lighting work?

What Is Emergency Lighting?

Emergency lighting is designed to be used in the event of a power failure caused by an emergency. One of the most common examples is when a building is on fire and the mains power has gone out.

In this situation (and other emergencies), people must be easily able to navigate their way out of the building as quickly as possible. Without emergency lighting to illuminate corridors, lifts, stairs, exits and other important places, this would be incredibly difficult.

Types Of Emergency Lighting

When you decide to have emergency lighting installed, you may be asked which type you would like. There are two main types of emergency lighting and these are non-maintained emergency lighting and maintained emergency lighting.


Non-maintained emergency lighting is connected to the mains power system but doesn’t typically run unless there is a power failure. In the event of a power failure, non-maintained emergency lighting will react and automatically come on.


On the other hand, maintained emergency lighting is constantly running and, in some buildings, it is even used as an everyday light fixture. However, when the mains power fails, this lighting acts as a back up and continues to run, illuminating key areas of the building.

Does Emergency Lighting Rely On The Main Power System For The Building?

One of the main concerns for people is that since emergency lighting is connected to the mains power system, it will rely on this to work.

But that isn’t the case. While emergency lighting is indeed wired to your mains power, it also benefits from a backup battery which is what will power it when the mains power is out.

The benefit of being connected to the mains power system is that the backup battery is always being charged. This means that, in the event of a power failure, there will be enough juice to keep the lighting system running long enough to ensure that everyone is safely out of the building.

Generally speaking, emergency lighting batteries are designed to give up to three hours of illumination. However, this does vary depending on different products and situations so it’s always worth getting to know your system.

How Do I Know If My Emergency Lighting Is Functional?

As long as your emergency lighting is connected to your mains power and is charging then it should be pretty reliable. But, as is the case with anything, there is room for failure so including regular testing in your emergency lighting maintenance schedule is vital for the safety of your building.


It is recommended that you have an annual inspection which is performed by a qualified electrician. This will highlight any issues with the system and allow you to have them addressed. Keep in mind that emergency lighting is a legal requirement for commercial and business premises in the UK so having these annual checks will ensure your building is compliant.


However, outside of these checks, there are still things you can do to ensure that your emergency lighting continues to function. Even if everything was OK at the annual check, there’s still room for things to go wrong.


This is why monthly emergency lighting checks are a must and they’re very easy to carry out. Plus, these checks don’t have to be done by a qualified electrician.


It’s simply a case of switching off the mains power which should activate the emergency lighting. It is worth keeping in mind that some products will have a test switch on the unit so there’s no need to turn off the mains power to perform a check. In any case, you’ll want to inspect each unit to check that it is performing as it should.


Moreover, it’s also important to check the backup battery but this doesn’t need to be done as often. You can perform this check once a year by activating the emergency lighting and leaving it on for three hours (or however long your system is designed to last). If the lighting is not able to stay on for the full duration, this could indicate an issue with the battery and you’ll need to contact your electrician.

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