Buy emergency light test key switches and spare test keys. You use them to simulate a mains failure so you can check that your emergency lighting switches to battery, without turning off the whole lighting circuit at the distribution board. HM Government fire safety guidance notes that test facilities often take the form of a "fishtail" key inserted into a special switch near the main fuse board or next to the relevant light switches.
Test key switches and keys we stock
- Test key switches: the M2 Slimline 10A double-pole 1-gang emergency light test key switch (1010-057EL), a key-operated switch for manual testing of emergency lighting circuits.
- Spare keys: ESP Duceri EMTSK spare keys, a pack of two keys for ESP EMTS and EMTSLCD emergency light test switches. See more from ESP.
For the luminaires themselves, browse maintained emergency lighting, non-maintained emergency lighting or the full emergency lighting range.
How emergency light testing works
- Monthly function test. Guidance recommends operating the test facility each month for long enough to confirm that every emergency lamp lights.
- Annual full-duration test. Once a year the system is run for its full rated duration. Batteries typically take 24 hours to recharge afterwards, so plan when you run the test. Premises should not be reoccupied until the emergency lighting is fully working again, unless other arrangements are in place.
- Do not test at the MCB. Emergency lighting manufacturer Advanced advises that using an MCB or fuse that isolates the whole lighting circuit is not an acceptable way to test, because it could create a risk of injury during testing.
- Keep records. Record every test and fix any faults promptly. Further guidance is given in BS 5266-8, and a competent person should install test facilities.
Why buy from JEM Systems UK
Every product we sell is genuine, brand new and factory sealed. Listings show manufacturer part codes, so you can match the switch or key you need. Buy online with fast, tracked UK delivery, or contact our team if you are not sure which key fits your switch.
Emergency light test key FAQs
What is an emergency light test key switch?
It is a key-operated switch used to test emergency lighting. Turning the key simulates a mains failure, so the emergency lights switch to battery while you check them.
What is a fishtail key?
"Fishtail" is the common name for the key that operates many emergency light test switches. HM Government fire safety guidance uses this name. Before you order a spare key, check that it is compatible with your switch.
How often should emergency lights be tested?
Guidance recommends a monthly function test and an annual full-duration test, both recorded. Self-test and addressable systems automate some of this, but the results still need checking.


