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How to install a PIR sensor without crossing into notifiable work

Updated: 20.10.2026

How to install a PIR sensor on a UK porch is mostly aim, lux, and time, after the circuit is dead. A new circuit, a consumer unit, or a bath or shower zone is not a weekend experiment. A like-for-like swap outside those cases is usually not notifiable in England, and the work is still expected to meet BS 7671. The listings behind this sit on the [motion sensor comparison](/hub/burglar-protection/motion-sensor). If the lamp later fires with nobody there, go to [PIR sensor false alarms](/hub/burglar-protection/motion-sensor/sub/motion-sensor-false-alarms). You should leave knowing which dials are yours, and when to book a registered electrician.

How to install a PIR sensor on a UK porch is mostly aim, lux, and time, after the circuit is dead. A new circuit, a consumer unit, or a bath or shower zone is not a weekend experiment.

Our top picks

Philips Hue Philips Hue indoor motion sensor

Best overall

Philips Hue Philips Hue indoor motion sensor
9.6/10about £37.99
View offer
Maclean Maclean MCE468 B

Best value

Maclean Maclean MCE468 B
9.2/10about £10.96
View offer
SEBSON SEBSON IR_OUT_AA

Alternative

SEBSON SEBSON IR_OUT_AA
8.6/10about £13.99
View offer
On this page
  1. 1.When this is not a DIY job
  2. 2.Mains terminals and a walk test
  3. 3.Aim across the path, not at it
  4. 4.Battery sensors skip the consumer unit

When this is not a DIY job

In England, notifiable work includes a new circuit, a replacement consumer unit, and a bath or shower zone. Most like-for-like replacements fall outside that list. A porch PIR on the same cable, outside a bathroom, is the usual reading, and it is not proof the cable is sound. Scotland and Wales are not this English list. Stop if the cable is damaged, the head is wet, or an RCD trips when power returns. IP choice sits on the motion sensor buying guide.

Mains terminals and a walk test

Maclean and the SEBSON wall and ceiling heads expect a permanent live, a neutral, and a switched live. Isolate at the breaker and prove the old head is dead. If you cannot name the three conductors, stop. SEBSON reviewers call the terminal chamber too small for UK cable, and one Maclean report says the connectors would not grip. If the cover will not close, refit the old sensor. Outdoor dials run about 10 seconds to 15 minutes and about 3 to 2,000 lux. The mini SEBSON steps through 5 seconds, 30 seconds, 1, 3, 5, or 8 minutes, with lux only at 10 or 2,000.
Philips Hue Philips Hue indoor motion sensor

Testsieger

Philips Hue Philips Hue indoor motion sensor
9.6/10about £37.99
View offer

Aim across the path, not at it

A PIR notices heat crossing its beams more readily than heat walking straight at the lens. You can be inside a claimed 12 m and still arrive late if you walk straight at the head. A 2 to 2.5 m mounting height is a maker’s tip, not a figure printed for these Maclean or SEBSON listings. Keep the pattern off the pavement and off a shrub against a sun-warmed wall. Keep the first evening’s on-time short.

Battery sensors skip the consumer unit

Hue, Eve, Tapo, SONOFF, and BeiLan are not wired into a rose. Hue needs a Bridge and one CR2032. Eve needs a Thread border router, two AAA cells, and is only IPX3. Tapo needs an H100 or H200 and one CR2450. SONOFF needs Zigbee 3.0 and a CR2477: pull the paper tab or pairing never starts. BeiLan’s receiver plugs into a socket and the PIR takes three AAA cells that are not included. It chimes, and it does not switch a lamp. If the radio is unclear, read PIR vs smart motion sensor.

Common questions

Do I need an electrician to replace a porch PIR?
For a like-for-like replacement in England, outside a bath or shower zone, you usually do not need building-regulations notification. You still isolate the circuit, and the job still sits under BS 7671. A new circuit, a consumer unit, damaged cable, or water in the fitting is electrician work. Scotland and Wales are not this English notification list. If you cannot prove the head is dead, do not continue on a guess.
Why does it miss me when I walk straight at it?
The lens prefers heat that crosses the beams. A 12 m, 180° head can still see you late if you walk down the middle of the path into its face. Cross from the side, then tilt. Raising the aim lengthens the range and lowering it shortens it. If the miss remains, the listing angle may be optimistic, which battery-sensor reviews also report when a 7 m claim behaves more like 3 m.
Can I fit a ceiling PIR in a bathroom myself?
Not in a bath or shower zone. That location is notifiable in England and belongs with a registered electrician. The SEBSON IR_ES_A is IP20 and listed for indoor use. Reviews that mention showers are not an IP rating. A dry landing outside the zone is a different job. If you are unsure where the zone ends, do not guess with a live cable.
Where do the three wires go?
These mains PIRs expect a permanent live, a neutral, and a switched live, marked on that model’s sheet. Identify them with the power off. If the conductors will not enter a SEBSON chamber without force, stop. Battery sensors have no mains terminals at all. This page deliberately does not give a colour-to-terminal recipe you could follow inside a live consumer unit.
How do I fit a battery sensor that needs a hub?
Confirm the hub, then the battery, then the place. Tapo needs an H100 or H200. SONOFF needs Zigbee 3.0. Hue needs a Bridge. Eve needs a Thread border router close enough to avoid the dropouts reviewers describe. Remove any paper tab under the cell. Mount with the pad, magnet, or screws actually in the box, and walk across the lens. There is no switched live to land, and no app step will replace a missing hub.

Related pages

Best motion sensor

Motion sensor

Motion sensor buying guide: choose lamp, hub, or chime

PIR sensor false alarms: aim and heat, then replace

PIR vs smart motion sensor: a lamp tonight, or a hub

Sources

Public UK sources and the amazon.co.uk listings kept on 19 October 2026.

  1. Electrical Safety First, outdoor lighting (retrieved 19.10.2026)
  2. Approved Document P (GOV.UK PDF) (retrieved 19.10.2026)
  3. legislation.gov.uk, SI 2012/3119 regulation 6 (retrieved 19.10.2026)
  4. GOV.UK, when approval is not needed (retrieved 19.10.2026)
  5. KES Lighting, IP65 vs IP44 (retrieved 19.10.2026)
  6. Professional Electrician / Ovia, PIR and microwave sensors (retrieved 19.10.2026)
  7. DCC Electrics, PIR security lighting (retrieved 19.10.2026)
  8. Voltimum UK, motion-sensor interference (retrieved 19.10.2026)