Wired Alarm Sensor Installation Guide¶

Guide to installing wired alarm sensors for UK alarm systems covering cable types, routing, termination, zone configuration, and best practices for reliable detection.

Wired Alarm Cable Types and Tools¶

Wired alarm sensors provide the most reliable detection because they are not subject to radio interference or battery failure. The standard cable for UK alarm installations is 6-core alarm cable (6 strands of 0.22mm or 0.5mm solid copper core) with white PVC sheath. For longer runs over 50 metres use 8-core cable (0.5mm). Multi-core alarm cable costs £25-£40 per 100m roll from Screwfix or Toolstation. Tools required: cable strippers (£8-£15), wire cutters, small flat-blade screwdriver for terminal blocks, multimeter for continuity testing (£15-£30), and cable ties. Cable routing: run sensor cables from the control panel to each sensor location through ceiling voids, underfloor spaces, or along skirting boards. Avoid running alarm cables parallel to mains electrical cables (230V) - maintain 300mm separation per BS 7671. If crossing mains cables, cross at 90 degrees. Use cable clips every 300mm to secure the cable. For surface mounting use mini trunking (16x16mm, £3-£5 per 2m from B&Q). For in-wall routing use 20mm PVC conduit. Maximum cable run from panel to sensor is typically 100 metres for 0.5mm core cable.

Terminating and Configuring Wired Sensors¶

Door/window contacts: connect the two contact wires to the panel zone input and common/negative. Normally Closed (NC) contacts are standard for UK alarm systems - the circuit is closed (complete) when the door is closed. Wiring: brown wire to zone input, black wire to common negative. PIR detectors: connect 4 wires - 12V positive (red), 0V negative (black), alarm signal (yellow/white to zone input), tamper signal (green/orange to tamper input). At the control panel each zone input accepts one sensor. Label each cable at both ends before connection. Zone configuration in the alarm panel: set each zone as Entry/Exit (front door circuit), Immediate (internal PIR detectors), or Perimeter (ground floor windows). Wire all contacts in series on the same zone for windows on one side of the house. Use a multimeter to test continuity before closing the panel. Test each zone using the alarm panel walk test mode. A 0.5-1.0 second response time is standard for wired sensors. Wired installations typically take 4-8 hours for a 3-bedroom UK house.

Specifications and Comparison¶

Sensor Type	Cable Core Count	Zone Setting	Termination Method
Door/Window Contact	2-core NC	Entry/Exit or Perimeter	Screw terminal block
PIR Detector	4-core	Immediate	Screw terminal 12V/O/V/Alarm/Tamper
Shock Sensor	2-core NC	Perimeter or Immediate	Screw terminal
Glass Break Detector	4-core	Immediate	Screw terminal 12V/O/V/Alarm/Tamper
Smoke Detector	4-core + interlink	Fire (24hr)	Screw terminal with fire zone setting

FAQ¶

Is wired or wireless alarm better for my UK home?: Wired systems are more reliable (no battery changes, no radio interference) but harder to retrofit. Wireless is easier to install and suits retrofits. Wired is preferred for new builds and major renovations where the walls are open.
Can I mix wired and wireless sensors?: Yes - most UK alarm panels support hybrid setups. Connect wired sensors to the onboard zones and use a wireless expander (RXR for Texecom or WBE for Pyronix) for wireless sensors in difficult-to-cable locations.
What cable should I use for wired alarm sensors?: Standard 6-core alarm cable (0.22mm or 0.5mm) for most sensors. Use 8-core 0.5mm for runs over 50 metres. Avoid using Cat5/6 data cable for alarm sensors - the core diameter is too small for reliable termination in alarm terminals. For more information see our Glass Break Detector Installation Guide.

Last updated: 2026-05-31.

External Resources¶

For further information consult authority guidelines at the Ofcom.