Wiring
Reference
Cable specifications, colour codes, EOL resistors and wiring diagrams for every system type.
Fire Alarm Cable
BS 5839-1 requires that all fire alarm wiring uses enhanced fire performance cable. Standard PVC cable must never be used for fire alarm circuits. The cable must maintain circuit integrity for a defined period under fire conditions.
| Cable Type | Standard | Fire Resistance | Typical Application | Notes |
|---|
| FP200 Gold | BS 7629-1 | E30 (30 min) or E60 (60 min) | Standard fire alarm wiring in most buildings | Most common choice. Available in 2-core, 4-core. Cream/orange sheath. |
| MICC (Pyrotenax) | BS EN 60702-1 | E120 (120 min) | High-risk environments, sprinkler systems, escape routes | Mineral insulated copper clad. Requires specialist termination. Highest fire resistance. |
| FP Plus | BS 7629-1 | E30 or E60 | Alternative to FP200 Gold | Similar performance. Check manufacturer data sheet. |
| Firetuf OHLS | BS 7629-1 | E30 or E60 | Low smoke zero halogen environments | LSZH sheath. Used in tunnels, public transport, hospitals. |
| Standard PVC | BS 6004 | None | NOT suitable for fire alarm | Must never be used for fire alarm circuits. |
FP200 Gold — Typical Specifications
| Parameter | 2-Core | 4-Core |
|---|
| Conductor CSA | 1.5mm² (standard) | 1.5mm² (standard) |
| Conductor resistance | 12.1 Ω/km | 12.1 Ω/km |
| Sheath colour | Cream/orange | Cream/orange |
| Overall diameter | ~6.5mm | ~8.5mm |
| Operating temperature | -20°C to +70°C | -20°C to +70°C |
| Voltage rating | 300/500V | 300/500V |
Intruder Alarm Cable
| Cable Type | Cores | Application | Notes |
|---|
| 6-core alarm cable | 6 × 0.22mm² | PIR detectors, door contacts | Standard intruder alarm cable. White or grey sheath. LSF or LSZH. |
| 4-core alarm cable | 4 × 0.22mm² | Simple door contacts, reed switches | Where fewer cores needed. |
| 2-core alarm cable | 2 × 0.22mm² | Bell/sounder circuits, simple loops | Basic circuits only. |
| Screened alarm cable | 4-core screened | PIRs in electrically noisy environments | Screen provides EMC protection. Connect screen at one end only. |
| Mains cable (3-core) | 3 × 1.5mm² | Panel mains supply | Must be wired by qualified electrician. Dedicated circuit from consumer unit. |
Typical 6-Core Colour Code (Intruder Alarm)
| Core Colour | Typical Use |
|---|
| Red | +12V positive supply |
| Black | 0V negative / common |
| Yellow | Zone A / tamper |
| Green | Zone B / loop return |
| Blue | Auxiliary / trigger output |
| White | Auxiliary / data |
EOL Resistor Values by Panel
End-of-line (EOL) resistors are placed at the furthest point of each detection zone to allow the panel to supervise the circuit. The panel monitors the resistance — an open circuit (cable cut, device removed) or short circuit (cable damage, tamper) changes the resistance and triggers a fault or alarm.
| Panel Manufacturer | Panel Model | EOL Value | Double-Pole EOL | Notes |
|---|
| Honeywell/Resideo | Galaxy Dimension | 1kΩ | Yes (Grade 3) | Standard 1kΩ for Grade 2. Double-pole (1kΩ + 1kΩ) for Grade 3 tamper supervision. |
| Honeywell/Resideo | Galaxy Flex | 1kΩ | Yes (Grade 3) | Same as Dimension. |
| Honeywell/Resideo | Galaxy MK7 | 1kΩ | No | Legacy panel. Grade 2 only. |
| Texecom | Premier Elite series | 1kΩ | Yes (configurable) | Default 1kΩ. Can be changed to 2.2kΩ or 4.7kΩ in zone programming. |
| Pyronix | Enforcer / Matrix | 2.2kΩ | Yes (configurable) | Default 2.2kΩ. Configurable per zone in Enforcer software. |
| Eaton | i-on series | 4.7kΩ | Yes | Standard 4.7kΩ. Check zone programming for custom values. |
| DSC | Neo / PowerSeries | 5.6kΩ | Yes | Default 5.6kΩ. Configurable in programming. |
| Risco | LightSYS 2 | 2.2kΩ | Yes | Standard 2.2kΩ. |
| Bosch | Solution 3000/6000 | 1kΩ | Yes | Standard 1kΩ. |
| Optex/Crow | Runner/Crow series | 2.2kΩ | No | Standard 2.2kΩ. |
Data Cable — Cat6 / T568B
Cat6 UTP or STP cable is used for IP CCTV, IP access control, and network infrastructure. The T568B wiring standard is the most common in the UK for RJ45 terminations.
T568B Wiring Standard (Most Common in UK)
| Pin | Colour | Function |
|---|
| 1 | Orange/White | TX+ (Transmit positive) |
| 2 | Orange | TX- (Transmit negative) |
| 3 | Green/White | RX+ (Receive positive) |
| 4 | Blue | Unused (PoE) |
| 5 | Blue/White | Unused (PoE) |
| 6 | Green | RX- (Receive negative) |
| 7 | Brown/White | Unused (PoE) |
| 8 | Brown | Unused (PoE) |
PoE Standards Reference
| Standard | IEEE | Max Power (per port) | Typical Application |
|---|
| PoE | 802.3af | 15.4W | Basic IP cameras, VoIP phones, access readers |
| PoE+ | 802.3at | 30W | PTZ cameras, video door entry, wireless APs |
| PoE++ | 802.3bt (Type 3) | 60W | High-power PTZ, multi-radio APs |
| PoE++ | 802.3bt (Type 4) | 100W | Thin clients, high-power devices |
Cable Resistance Reference
| CSA | Resistance (Ω/km) | Resistance (Ω/100m) | Max one-way run (100Ω limit) |
|---|
| 0.22mm² | 83.0 Ω/km | 8.3 Ω/100m | 602m |
| 0.5mm² | 36.0 Ω/km | 3.6 Ω/100m | 1,389m |
| 1.0mm² | 18.1 Ω/km | 1.81 Ω/100m | 2,762m |
| 1.5mm² | 12.1 Ω/km | 1.21 Ω/100m | 4,132m |
| 2.5mm² | 7.41 Ω/km | 0.74 Ω/100m | 6,748m |
Note: Loop resistance is the round-trip resistance (cable out + cable back). For a 50m run of 1.0mm² cable, the loop resistance = 18.1 × 0.1 × 2 = 3.62Ω. Always check against the panel's maximum zone resistance specification.