BS5266-1 states that emergency lighting should be regularly tested.
BS5266-1 states that emergency lighting should be tested as follows:
There are three widely used ways to test emergency lighting. To understand them it is necessary to understand first how an emergency light fitting is wired. Note that the remarks that follow apply to self-contained emergency fittings, not to central battery operated emergency fittings.
Terminal wiring diagram for a class I maintained emergency light fitting.
Terminal wiring diagram for a class I non-maintained emergency light fitting.
L SW is the normal mains supply. A normal light switch, or sensor, would usually be on this circuit to enable the end-user to have control over the light fitting in normal operating mode. L SW is always to be wired so that any switching of L PERM will disconnect L SW too, but any switching of L SW will not affect L PERM.
L PERM is the permanent live supply and must have no normal (manually operated) switch or sensor on it. However, a key-switch is permissible and will usually be installed on this circuit. L PERM has two functions:
1.It supplies the power that keeps the emergency batteries charged. That’s why it must not be affected by any switching of L SW.
2.When zero voltage is detected at L PERM it is the indication to the emergency module in the light fitting that mains power has been lost and that battery power must now be switched on.
A key-switch. This is installed on the permanent live supply to an emergency fitting. When actuated it isolates the emergency fitting, thus simulating a power failure.
The 3 commonly used methods of testing emergency lighting are as follows:
Manual test button.
This performs the same function as a key-switch, isolating the fitting from its permanent live supply and thereby simulating a power failure.
Self-test has several benefits. First, it saves the labour of manual testing. Secondly, it removes the risk that routine monthly or annual testing is overlooked.
Addressable self-test is well suited to large projects and large, distributed estates such as hospitals, colleges, university campuses and business parks.
Several different technological approaches to addressable self-test can be taken, including wired (often using DALI as the communications protocol), as well as wire-free using a range of Rf protocols including Bluetooth, Zigbee and other proprietary technologies.