Why is my security light stuck on all the time?

A security light stuck on all the time usually means the PIR is in override/test mode, the sensor has failed, or wiring is feeding the lamp permanently. In UK homes a short power-off reset often clears override; if the security light stays on after that, the PIR or outdoor wiring needs an electrician.

Is a security light that won't turn off a fire risk?

A security light that won't turn off can be a fire risk if it is an older halogen fitting left on continuously. Those lamps run very hot. LED security lights are cooler but still should not stay powered if wiring is faulty. If the housing is discoloured, smells of burning, or is surrounded by debris, isolate the light if safe and call an electrician.

Why does my security light come on during the day?

A security light that comes on during the day often has a lux/daylight sensor set too low, a failed photocell, or a PIR stuck in override. Heat sources near the sensor can also keep a security light triggered in daylight. Adjust dials only with the fitting isolated; replace the sensor or call an electrician if daylight behaviour never returns.

How do I reset a PIR security light that won't turn off?

To reset a PIR security light that won't turn off, switch it off at the wall for at least 30 seconds, then restore power and wait for the warm-up cycle. Avoid rapid flicking of the switch unless the manufacturer instructions say that enters (or exits) override. If the security light remains on after a clean reset, the PIR may need replacing.

Can a power cut or flicking the switch leave a security light always on?

Yes. Many UK PIR security lights enter override or test mode after a power cut or after the supply is switched on and off quickly. That can leave a security light on until you power-cycle it correctly or until an electrician clears a failed control board.

Could a boiler flue or heat source keep my security light on?

Yes. A security light with a PIR aimed at a boiler flue, tumble-dryer vent, air-conditioning unit, or warm wall can stay triggered by heat rather than people. Re-aiming or relocating the PIR often stops a security light that won't turn off for this reason. An electrician can do this safely if the fitting is high or hard-wired.

What's the difference between a floodlight stuck on and a PIR security light stuck on?

A floodlight stuck on and a PIR security light stuck on are often the same symptom: permanent power to the lamp. Some floodlights are switched only (no PIR); others combine floodlight optics with a PIR. Treat both as "lamp circuit held on," check override/reset first, then book an electrician if outdoor wiring or the sensor has failed.

How much does it cost to fix or replace an outdoor PIR security light?

Tradehand's related cost guide for electrician garden lighting installation is typically £150–£450 depending on scope. A simple PIR swap on an existing outdoor circuit may sit toward the lower end; new outdoor runs cost more. Confirm for your property on Instant Quote, not a fixed price.

Low risk

Updated 11 September 2026

Security Light Won't Turn Off

Your security light is stuck on permanently and will not turn off, even during the day. In UK homes this is usually a stuck PIR sensor, override/test mode, or a wiring fault, often fixable with a safe reset, but call an electrician if the light stays live after isolation checks or you smell burning.

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What's happening?

A security light that won't turn off means the outdoor fitting is receiving power when it should be dark-sensing or motion-only. Most UK PIR (passive infrared) security lights should stay off in daylight and only illuminate briefly after movement. When a security light stays on all the time, the PIR, override switch, timer dials, daylight sensor, or wiring may be holding the lamp circuit closed. This is usually a low-risk nuisance rather than an emergency, but a light that never cools down can waste electricity and, on older halogen fittings, raise heat and fire risk around the housing. Any of these can leave a security light on through the day as well as at night.

What usually causes it?

A stuck or failed PIR sensor that never releases the lamp
Manual override or "always on" mode left engaged at the wall switch or fitting
Power-cycle override / test mode after a power cut or after flicking the switch several times
Timer dials or lux (daylight) settings set so the security light ignores daylight
A wiring fault that bypasses the PIR and feeds the lamp permanently
Constant heat or movement near the PIR (boiler flues, air-conditioning units, vents, busy roads) keeping the sensor triggered

Is it dangerous?

A security light stuck on is usually low risk compared with shocks or sparking faults, but it is not always harmless. Older halogen security lights run very hot when left on continuously and can become a fire risk if leaves, birds' nests, or plastic covers sit against the fitting. LED security lights run cooler but still waste power and can hide a wiring fault if the PIR has been bypassed. If the security light housing is discoloured, smells of burning, buzzes, or the consumer unit trips when you try to isolate it, treat that as urgent and call an electrician. For a simple "always on" PIR with no heat or smell, safe DIY checks first are reasonable in the UK, then book a pro if it stays on.

Can I fix it myself?

You can try safe isolation and setting checks on a security light that won't turn off. Do not open junction boxes, cut outdoor cables, or work at height in wet weather: 1. Turn the security light off at its wall switch (or isolator) for at least 30 seconds, then restore power. Many PIR units exit override/test mode after this reset. 2. Check whether a wall switch has been flicked rapidly (often used to force override); return it to a normal on/off position and wait for the PIR cycle to finish. 3. If accessible from the ground with the light isolated, check timer / lux / sensitivity dials on the PIR so daylight sensing is not disabled. 4. Look for heat sources aimed at the PIR (boiler flue, dryer vent, AC) that could keep a security light falsely triggered. 5. Confirm the fitting is LED or halogen only by the manufacturer label once isolated. Do not assume lamp type by eye in the dark. Stop DIY and call an electrician if the security light stays on after a proper reset, you cannot isolate it safely, the fitting is damaged, or outdoor wiring looks burnt or waterlogged. Outdoor electrical work beyond simple isolation should be done by a competent person; for new circuits or consumer-unit work in England and Wales, Part P / registered electrician rules apply.

When should you call an electrician?

Call an electrician for a security light that won't turn off if: the light stays on after a 30-second power-off reset and override checks; the security light comes on during the day and never respects the daylight sensor; you smell burning, see scorch marks, or the fitting is too hot to approach safely; the consumer unit trips, or outdoor cables look damaged or water-ingressed; the light is on a shared supply, rented property, or you are not confident isolating it; or you need the PIR replaced, rewired, or a new outdoor fitting installed. This page is low risk for a simple stuck-on PIR. It is not the same urgency as electric shocks, but do not leave a hot halogen security light burning unattended for days.

What will the electrician actually do?

Isolate the outdoor circuit and confirm whether the lamp is permanently live or PIR-controlled
Test or replace a stuck PIR sensor / photocell on the security light
Check wall-switch override wiring and any intermediate switches
Inspect outdoor junction boxes for water ingress or a bypass that feeds the lamp constantly
Replace a failed halogen or LED lamp and housing if heat damage is present
Re-aim or relocate the PIR if boiler flues or vents are causing false triggers
Advise on a like-for-like outdoor fitting replacement where the unit is beyond repair
Related ballpark already on Tradehand for this topic: electrician garden lighting installation commonly £150–£450 depending on the job. Confirm on Instant Quote rather than treating that as a fixed price for a single PIR swap.