What cable size do I need for a CCTV system?

For the mains supply to POE switch/NVR, typically 2.5mm² on a 16A circuit is adequate. Most home systems can use a 13A socket. The camera cables are Cat6 ethernet, not mains cable. Only the central equipment needs mains power.

Do I need mains power to each camera?

Not with POE systems. The cameras receive power through the ethernet cable from the POE switch or NVR. Only the central equipment (NVR, POE switch) needs mains power. This dramatically simplifies installation.

What about non-POE analogue cameras?

Older analogue systems may need separate 12V DC supplies at each camera location, run from a central PSU. Modern IP/POE systems are preferred for new installations as they need only Cat6 cable to each camera location.

How far can I run POE cables?

Standard POE works up to 100m over Cat5e/Cat6 cable. For longer runs, use POE extenders or fibre optic with media converters. Voltage drop over long Cat6 runs can reduce available power - keep runs under 80m for reliability.

Do CCTV circuits need RCD protection?

Indoor CCTV equipment doesn't specifically require RCD protection beyond normal consumer unit arrangements. Outdoor cameras on POE don't need mains RCD as they're low voltage. Any outdoor mains circuits (e.g., for separate camera PSUs) need 30mA RCD.

What about intruder alarm panels?

Alarm panels typically draw 1-3A from mains via their built-in PSU. A 3A fused spur from the ring main is standard, with unswitched supply to maintain power. The panel has battery backup for mains failure - usually 12V 7Ah batteries.

Should CCTV have battery backup?

For security systems, UPS (Uninterruptible Power Supply) backup is recommended. A UPS maintains recording during power cuts. Size the UPS for total system load plus runtime needed - 30 minutes to several hours depending on requirements.

Can I use existing telephone/data cables for cameras?

Cat5e can work for POE over short distances, but Cat6 is preferred for new installations. Old telephone cables are not suitable. For best performance and future-proofing, install new Cat6 cable for each camera location.

What about wireless cameras?

Wireless cameras still need power - either mains via a plug/fused spur, or battery. Battery cameras have limited recording time and need recharging. Wired POE systems are more reliable for permanent installations.

Is Part P notification required for CCTV installation?

Adding a socket or fused spur in a normal location is not notifiable. However, new circuits in kitchens, bathrooms, or outdoors are notifiable. The Cat6 cabling is data/low voltage and not covered by Part P.

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CCTV & Security System Cable Sizing Calculator

Calculate the correct cable size for CCTV, security cameras, and alarm system installations

CCTV & Security Cable Quick Facts

Most CCTV systems use POE (Power over Ethernet) - no separate mains needed per camera
POE switch/NVR typically needs 200-500W mains supply
Intruder alarm panels typically draw 1-3A from mains PSU
Battery backup essential for security systems
Cat6 cable for POE runs up to 100m

Cable Size Calculator

BS 7671:2018+A2:2022 compliant

1. Load Current

2. Cable Length (meters)

3. Installation Method

Lighting circuit (3% voltage drop limit)

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Common Security Installations

Small home CCTV (4 POE cameras)

Single 13A socket for NVR/switch, Cat6 to cameras

Medium system (8 POE cameras)

16A circuit for POE switch, consider dedicated circuit

Large system (16+ cameras)

Dedicated circuit, possibly multiple POE switches

Intruder alarm panel

3A fused spur from ring main, battery backup

Commercial security suite

Dedicated circuits, UPS backup, cable tray installation

Complete Property Security

CCTV pairs with electric gate automation for comprehensive property access control. For garden offices and outbuildings with security cameras, see our garden building electrical guide. Commercial premises may also need dedicated circuits for various equipment.

Security System Cable Sizing

Security system cable sizing covers both mains supply (to NVR, POE switches, alarm panels) and low-voltage cabling (Cat6 for POE cameras, alarm wiring). Modern POE systems simplify installation - a single mains supply powers the switch, which then delivers power and data to cameras over Cat6 cable.

Security System Installation Costs (2024)

Typical UK electrical installation costs. Does not include cameras, NVR, or alarm panel.

Installation Scenario	Materials	Labour	Total
Dedicated circuit for NVR/POE switch	£60-120	£100-180	£160-300
Fused spur for alarm panel	£30-60	£60-120	£90-180
Cat6 cable runs (per camera)	£20-50	£40-80	£60-130
Outdoor camera SWA supply	£100-200	£150-280	£250-480
UPS installation for security	£150-400	£80-150	£230-550

Prices as of 2024. Cat6 cable runs are per camera location.

POE (Power over Ethernet)

POE delivers power and data over standard Cat5e/Cat6 ethernet cable. POE cameras don't need separate mains supplies - they receive power from the POE switch or NVR. Standard POE provides 15W per port, POE+ provides 30W, and POE++ provides up to 100W for PTZ cameras and heated housings.

NVR Power Requirements

Network Video Recorders (NVRs) typically draw 50-150W depending on size and number of hard drives. POE NVRs with built-in POE ports need additional power budget for connected cameras - typically 15-30W per camera. Calculate total load when sizing the supply circuit.

Alarm Panel Battery Backup

BS EN 50131 Grade 2 alarm systems require 12-hour battery backup. Grade 3 requires 60 hours. The mains PSU charges the backup batteries while powering the system. If mains fails, batteries maintain full operation. Regular battery testing and replacement (typically every 3-5 years) is essential.

Frequently Asked Questions

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