Fire systems live or die by cable quality. Detectors, sounders, and control equipment only work as designed when the wiring is correct, protected, and documented. Australian projects also sit under a clear framework: the NCC points to AS 1670.1 for fire detection and alarm systems, which shapes design and installation practice. Treat that link as your baseline.
Using the wrong cable for the duty
Not every circuit needs fire-resisting cable, yet some do. Where a circuit must keep operating during a fire, select wiring systems tested to AS/NZS 3013. You will often see WS classifications such as WS52W on product data sheets. That code indicates performance under heat and mechanical stress when installed as a system, not just as a loose cable. Confirm the specified rating against the design brief and the equipment function.
A common slip is substituting general TPS for a path that the design expects to survive for a defined period. For example, control lines to an occupant warning system may require a WS-rated wiring system. Do not rely on colour alone to imply suitability.
Poor segregation from mains and data
Running fire alarm loops beside 230 V feeders or high-noise data trunks invites interference and intermittent faults. AS/NZS 3000 requires segregation between circuits of different types and voltages, achieved by spacing or barriers within containment. Keep fire alarm and EWIS cable away from mains and from sources of electromagnetic noise. Where crossings are unavoidable, cross at right angles and keep the path short.
Misusing TPS styles and colours
Colour should aid identification, not replace compliance. Site teams sometimes grab Flat red TPS cables for convenience because the sheath looks “fire”. That practice can break the specification if the circuit needs a fire-resisting wiring system or screened twisted pair. Check the drawings and the equipment schedule before pulling any run.
Later in a project, maintenance techs may confuse look-alike sheaths. Clear labelling at panels and junction boxes helps. If you carry Flat red with white stripe TPS cables, mark where they are used and why. Keep a register so replacements match the original design intent.
Bad terminations and EOL errors
Loose terminations, stray strands, and poorly crimped ferrules cause ground faults and unstable loops. The worst offender is often the end-of-line resistor. Each control panel family expects a specific value and placement. Fit the resistor at the true remote end, not inside the panel for convenience. Wrong values or wrong location confuse supervision and can block an alarm condition. Always check the manufacturer’s table for the panel you are wiring and record any zone variations in the logbook.
Excessive joints and inaccessible junctions
Every hidden joint is a future call-out. Joints create resistance, corrosion points, and nuisance earths. Where a joint is unavoidable, use an enclosure with strain relief and leave it accessible. Support cables so the termination screws are not carrying the weight. That small step prevents creep and broken conductors months after handover.
Ignoring bend radius and pull tensions
Fire cable insulation stiffens at low temperatures and softens with heat. Tight bends nick insulation and damage shields. Follow the manufacturer’s minimum bend radius, especially at risers and above ceiling grids. Use rollers on long pulls and avoid twist as you feed the drum.
Undersized conductors and voltage drop
Long loops and multiple devices add up. Undersized conductors starve sounders and remote modules under alarm current. Designers should calculate voltage drop and select cable size to meet device limits with margin. During commissioning, measure loop impedance and verify device supply under full load. If you inherit a job, document the readings so future trades can spot degradation.
Mixing unscreened and screened pairs
Audio evacuation and detector loops often require twisted, sometimes screened, pairs to control crosstalk. Do not mix cable types on the same circuit. Resist the temptation to improvise a Twisted TPS cable by twisting twin-and-earth; it will not mimic a true twisted pair and may fail compliance. Order the correct pair early and keep spare drums for site changes.
Bad routing near heat and water
Cables above commercial kitchens and plantrooms face heat, steam, and cleaning chemicals. Avoid duct penetrations that drip onto junctions. Keep clear of sharp-edged tray sections and vibrating fixings. In car parks, route above the spray zone and protect drops with conduit.
Weak identification and records
Missing labels cost more than they save. Label both ends of every run with the loop or zone ID. At the panel, label terminations and include a printed index behind the door. Update drawings whenever a device moves. Good records turn future fault-finding into minutes, not hours. The NCC link to AS 1670.1 means documentation is part of demonstrating compliance, not an optional extra.
Quick fault-prevention table
| Fault pattern | What happens on site | How to prevent it |
| Wrong cable rating | Circuits fail when exposed to fire or impact | Select AS/NZS 3013-rated wiring systems where required; verify WS code on data sheet |
| No segregation | Induced noise, phantom alarms | Maintain separation or barriers per AS/NZS 3000; avoid parallel runs with mains |
| EOL mistakes | Constant fault or no alarm | Use the panel’s specified resistor value; fit at the true end; record in logbook |
| Hidden joints | Intermittent faults, high resistance | Minimise joints; keep enclosures accessible and strain-relieved |
| Tight bends | Insulation damage, earth faults | Observe minimum bend radius and use rollers on long pulls |
| Mixed pair types | Crosstalk, muffled EWIS audio | Use the specified twisted or screened pair for the entire circuit |
Site checklist you can apply today
- Read the drawings and the fire matrix before ordering cable.
- Confirm where WS-rated wiring systems are specified, and why.
- Plan routes that respect segregation and avoid high-noise areas.
- Terminate neatly, torque screws, and photograph each panel row.
- Fit the correct EOLs at the remote ends and label the box lids.
- Update the cable schedule when a run changes on site.
- Train maintenance staff on the site’s labelling scheme and testing routine.
Cabling is not just copper and plastic. It is the backbone that lets detectors talk, sounders warn, and controls actuate. Follow the standards, document your work, and refuse shortcuts that look harmless but come back as late-night call-outs. Your future self will thank you.
