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A Guide to Emergency Lighting - FAQs


What cable should be used for emergency lighting?

  • Self-contained emergency light fittings (ie emergency light fittings that each have their own batteries) are typically wired with 1.5mm² 4-core, as follows:
  • Switched live
  • Earth
  • Neutral
  • Permanent live

A 4 core cable used for emergency fittings



A 4-core cable of the type widely used for lighting circuits that include self-contained (not central battery) emergency fittings.


  • Central battery emergency light fittings require a specialised fire resistant cable to connect the fitting to the central batteries.

Should emergency lighting be on all the time?

Emergency lighting should always be connected to its power source, but it does not need to be always illuminated. Self-contained emergency light fittings (ie emergency light fittings that each have their own batteries) can be installed as maintained or non-maintained. If they are maintained they will be switched on and off just like a normal light fitting, but they will have an additional live supply (called the permanent live, and which is un-switched) whose function is to keep the batteries fully charged. If they are non-maintained, they will be off most of the time and will only switch on in the event of a power failure.

How do I know if my emergency lighting is working?

There are three main ways to tell if your emergency lighting is working or not:

1. A green indicator LED, installed on or beside each emergency light fitting, will be illuminated. This means that the emergency fitting is connected and its batteries are charging.

2. If the fitting is disconnected from mains the green LED indicator will switch off and the fixture will illuminate using its battery power. This is another sign of correct function.

3. Emergency lighting should be tested briefly every month and should undergo a full duration test (normally 3 hours) at least once every year. This should be carried out by a “Competent Person” (as defined in the Regulatory Reform (Fire Safety) Order 2005. If it does not pass the test it should either be repaired or the “Responsible Person” should be informed.

How often should emergency lighting batteries be changed?

Emergency lighting batteries should be changed at the earliest date of either:

  • When they cease to deliver the duration (usually 3 hours) for which they were designed.
  • The end-of-life as advised by the manufacturer. For nickel-cadmium (NiCd) and nickel metal hydride (NiMH) this is typically 3 years, for lithium batteries it is longer and will vary from one manufacturer to another.

Can I use an emergency light as a normal light?

Yes. If the emergency light fitting is installed as a maintained emergency light fitting it will function as a normal light fitting and switch to emergency (battery operation) when mains power fails.

Do you need emergency lighting in toilets?

As specified in BS5226-1, if the toilet in question is designed for the use of only a single able-bodied person or if it is an en-suite facility in a hotel bedroom then emergency lighting is not required.

Multiple closet facilities without borrowed light and toilets for use by disabled people both require emergency lighting.

Is emergency lighting required in small offices?

According to BS5266-1, a small room of not more than 12m² with no specific risks identified in the risk assessment does not require emergency lighting.

However, if such a small room can only be exited via a second small room then that second small room is the escape route for the first small room and the second room will require emergency lighting.

Is emergency lighting required in medium sized offices?

According to BS5266-1 a medium sized office of not more than 60m² does not require emergency lighting if it is not itself part of the escape route from the building.

Where should emergency lighting be installed?

Emergency lighting should be installed in almost all buildings that are used by the public or employees. This is a requirement of the Regulatory Reform (Fire Safety) Order 2005 and of the Building Regulations 2010 Fire Safety Approved Document B. To determine the type, location and quantity of emergency lighting required you are advised to read What are the regulations & standards governing emergency lighting?