WiremanWireman · Emergency or exit light fails its test: troubleshooting for electricians · 2023 NEC ·
Emergency or exit light fails its test
Unit won’t light on the test button, dies before 90 minutes, shows no charge, or stays on with power on.
Before you start
How much electrical experience do you have?
This sets how much detail each step shows. You can change it any time.
Showing detail
How it works
Unit equipment has a battery, a charger and a transfer circuit that watches its normal supply. When normal power drops, it switches the lamps to the battery. Life-safety rules (NFPA 101, adopted by the local fire code) generally call for a 30-second functional test every month and a 90-minute test once a year, with written records. The unit should be fed from the same branch circuit as the normal lighting in its area, ahead of any local switch, so it sees the same outage the lights do. Batteries wear out with age and heat and are the most common failure.
Every question and answer in this guide. Tap “Step by step” to walk through it.
- What did the unit do?
- Didn’t light on the 30-second testTest: Measure the batteryExpect: At or a little above the nominal voltage at rest, and only a small dip while the test button is held.
- Well below nominal, or collapses under loadA worn-out battery
- Battery holds, lamps stay darkFailed lamps, heads or the unit’s board
- Battery unplugged or a terminal looseBattery disconnected
- Lit, but went out before 90 minutesBattery capacity too low for 90 minutes
- Charge or AC indicator is offTest: Measure the unit’s normal supplyExpect: Steady voltage that matches the lead it’s connected to, from an unswitched circuit.
- No voltage, or it goes off with a switchNo normal supply, or a switched supply
- Wrong voltage for the lead usedUnit connected to the wrong voltage input
- Correct voltage, unit still misbehavesFailed lamps, heads or the unit’s board
- Lamps stay on with normal power onTest: Measure the unit’s normal supplyExpect: Steady voltage that matches the lead it’s connected to, from an unswitched circuit.
- No voltage, or it goes off with a switchNo normal supply, or a switched supply
- Wrong voltage for the lead usedUnit connected to the wrong voltage input
- Correct voltage, unit still misbehavesFailed lamps, heads or the unit’s board
- Didn’t light on the 30-second testTest: Measure the batteryExpect: At or a little above the nominal voltage at rest, and only a small dip while the test button is held.