Testing an emergency light comes down to one question: will it keep working when the power goes out? To find out, the technician cuts the normal power supply to the lights, usually with a dedicated test switch, so every emergency light and exit sign switches over to its battery. The lights then need to stay lit for at least 90 minutes, which is the discharge test that AS/NZS 2293.2 requires every six months. This guide walks through what happens at each step, what the test switch actually does, and how manual, automatic and self testing systems differ.
What Does an Emergency Light Test Switch Do?
n emergency light test switch is a key or push button switch, usually mounted in or next to the building’s switchboard, that lets a technician run a discharge test without actually shutting the power off. In normal operation, the switch keeps mains power flowing to the emergency lights so their batteries stay charged. When the test starts, it disconnects that supply, which makes every emergency light and exit sign on the circuit behave as if there’s been a real power failure.
Many test switches include a built in timer. On the NHP model, for example, the timer can be set to 90 minutes for the routine six monthly test or 120 minutes for commissioning a new system, with extra time added so the technician can walk the building and check each fitting. When the timer runs out, mains power comes back on and the batteries start recharging.
Not every building has one. Without a test switch, the technician has to isolate the emergency lighting circuits at the switchboard by hand, which takes longer and is easier to get wrong on a large site. Either way, the goal is the same, which is why professional exit light testing always starts with simulating that power failure safely.
Manual, Automatic and Self Testing Systems
There are three ways an emergency lighting test can be run, and the right one depends mostly on the size of the building and how the system was installed.
Manual testing. A technician starts the test with the test switch, or by isolating the emergency lighting circuits at the switchboard, then walks the building to check every light and sign over the 90 minutes. Each result is written into the logbook by hand. It’s the most common method in small and medium buildings, and it needs no special equipment beyond the switch.
Automatic (monitored) testing. The emergency lights are connected to a monitoring system, either wired or wireless, that runs the discharge tests on a schedule and records the result for every fitting. Faults show up on a panel or in software, so a technician only needs to attend the fittings that failed. It suits large sites with hundreds of lights.
Self testing fittings. Each light has a built in chip that runs its own discharge test on a set schedule and stores the result. Some newer products report through an app and produce a PDF test report, which replaces the paper logbook.
Automatic and self testing systems cut down the time spent running tests, but they don’t remove the need for someone on site. The annual service still includes cleaning the fittings and a visual check that every light and sign works as intended, and any light that fails still has to be repaired, retested and recorded.
The 90 Minute Discharge Test, Step by Step
Here’s what happens during a routine six monthly discharge test:
- Check the batteries are fully charged. The emergency lights need to have been on normal power long enough beforehand for the batteries to be at full charge, otherwise a healthy light can fail the test.
- Simulate the power failure. The technician activates the test switch, or isolates the emergency lighting circuits, so every light and exit sign switches to battery power.
- Confirm everything comes on. Each fitting is checked straight away. Any light that doesn’t switch over at all is an instant fail.
- Wait out the 90 minutes. The lights run on battery for the full duration. New systems, or lights that have just had their batteries replaced, are usually tested for longer, often 120 minutes.
- Check every fitting at the end. At the 90 minute mark, the technician walks the building again to confirm each light is still lit and hasn’t dimmed noticeably. A lux meter can be used to measure the light output if there’s any doubt.
- Restore power and let the batteries recharge. Because the test drains the batteries, it’s best done when the building is quiet, with enough time for a full recharge before people are back in.
- Record the results and fix the failures. Every pass and fail goes into the logbook, failed fittings are repaired or replaced, and those lights are retested.
If you want to know what the standard says about how often this has to happen and what records to keep, our guide to emergency lighting standards in Australia covers it in full.
Frequently Asked Questions
How do you test emergency lights?
Emergency lights are tested by cutting the normal power supply, usually with a test switch, so each light runs on its battery. The lights must stay lit for at least 90 minutes, and every result is recorded in the logbook.
What is an emergency light test switch?
It’s a key or push button switch, usually in or near the switchboard, that disconnects mains power to the emergency lights to simulate a power failure. Many include a timer that restores power automatically once the test is finished.
How long does an emergency lighting test take?
The discharge test itself runs for 90 minutes, or longer for a new system or fresh batteries. Allow extra time on top for setting up the test and walking the building to check every light and exit sign.
Do self testing emergency lights still need servicing?
Yes. Self testing fittings run their own discharge tests, but the annual service still includes cleaning and a visual check, and any light that fails still needs to be repaired, retested and recorded.
Can I test emergency lights myself?
The testing should be done by a competent person with the right equipment to run and record a discharge test. In Queensland, it’s licensed work that requires a QBCC fire protection licence, so most building owners use a professional provider.
