What Is a Fire Alarm Cable Schedule?

A Fire Alarm Cable Schedule is a structured technical document that provides a complete, referenced record of every cable installed in a fire alarm system — its identification number, the zone or loop it serves, its start and end points, its cable type and specification, the route it follows, its measured length, and the results of all electrical tests carried out on it before and after installation.

It is not a drawing. It is a document that works alongside the fire alarm layout drawings to provide the detailed cable-level data that the drawings cannot practically show. Where the drawing shows the position of a detector and the general cable route, the cable schedule shows the specific cable reference, the exact cable specification used, the conduit reference it runs through, the measured length, the insulation resistance test result, and whether the cable passed or failed its acceptance tests.

Together, the fire alarm layout drawing and the cable schedule provide the complete technical picture of the installation. Either document without the other is incomplete. A fire alarm system handed over with drawings but no cable schedule is a system whose installation quality cannot be independently verified — and cannot be maintained correctly for the life of the building.

The cable schedule serves multiple audiences simultaneously. For the installation team, it is the reference document that defines which cable goes where and to what specification. For the commissioning engineer, it is the checklist that drives the pre-commissioning electrical testing programme. For the client and consultant, it is the quality record that demonstrates every cable was tested and verified before the system was energised. For the maintenance team, it is the baseline reference that makes fault diagnosis faster and more accurate for the life of the system.

Cable Types — Selection and Standards

The selection of the correct cable type for a fire alarm system is not a matter of preference or cost optimisation. It is a technical and regulatory requirement. Fire alarm cables must maintain circuit integrity during a fire event — meaning the cable must continue to carry the signal or power that activates the alarm even while the surrounding building is burning. Different cable types achieve this to different degrees, and different applications require different levels of fire performance.

Why Cable Type Matters During a Fire

The fundamental requirement for fire alarm cables is circuit integrity — the ability to continue carrying an electrical signal while surrounded by fire. NFPA 72 and BS 5839 both require that fire alarm circuit wiring maintains its function for a defined period during a fire event. This is not just a code compliance requirement. It is the physical mechanism that keeps the alarm system operational while the building burns — allowing detection signals to reach the panel, allowing the panel to drive the sounders, and allowing people to evacuate.

A fire alarm system installed with non-fire-resistant cable may function perfectly during normal operation and during testing. But when an actual fire occurs and the cable is exposed to high temperatures, the circuit fails — exactly when it is needed most. The cable type selection decision, made during procurement and documented in the cable schedule, is one of the most consequential quality decisions in a fire alarm installation.

Cable Sizing — Getting It Right

Cable sizing for fire alarm systems is determined by three factors: the loop resistance requirement defined by the FACP manufacturer, the voltage drop that occurs over the cable length, and the current-carrying capacity required for the circuit. For most standard fire alarm signal circuits, the dominant factor is loop resistance — the total resistance of the cable loop from the panel to the last device and back.

Standard Size Selection

• Detection loops — conventional systems: 2-core 1.0mm² is the minimum; 2-core 1.5mm² is strongly recommended for all runs over 50 metres and for any installation where long-term reliability is the priority
• Detection loops — addressable systems: 2-core 1.5mm² as standard; always check the FACP manufacturer’s data sheet for maximum loop resistance and capacitance limits
• Sounder and VAD circuits: 2-core 1.5mm² as standard; calculate voltage drop for runs over 50 metres to confirm the sounder receives adequate voltage at the end of the circuit
• Mains supply to FACP (230VAC): 3-core 2.5mm² as standard; this must be a dedicated circuit from the distribution board
• Long cable runs over 100 metres: Upsize to 2-core 2.5mm² and always calculate voltage drop — do not assume standard sizing is adequate

Cable Routing — Rules and Requirements

Cable routing defines the physical path that every cable takes from its source to its destination. The routing decisions made during installation have permanent consequences — for system performance, for maintenance accessibility, and for the fire resistance of the circuits. Every routing decision must be based on the approved drawings and must comply with the requirements of the applicable standard.

General Routing Principles

• Follow the approved drawing. Cable routes must follow the approved fire alarm layout drawing. Any deviation — because of a structural obstruction, a clash with another service, or a site condition not shown on the drawing — must be formally documented. Either raise an RFI before deviating, or update the as-built drawing after. A cable that follows a different route from the drawing without documentation is a defect waiting to be discovered at the next inspection.
• Minimum bending radius. Fire alarm cables must not be bent tighter than six times the cable outer diameter at any point in the installation. Sharp bends damage the conductor insulation and can cause insulation resistance failures that appear intermittently — the most difficult type of fault to diagnose and locate.
• Cable support intervals. Cables must be supported at maximum 1.5 metre intervals on cable trays and at maximum 750mm intervals in vertical runs. Unsupported cables sag, create mechanical stress at termination points, and are vulnerable to physical damage.
• Avoid heat sources. Route cables away from hot pipes, heating equipment, and high-temperature plant. The ambient temperature along the cable route affects the cable’s current-carrying capacity and its long-term insulation integrity. Where routing near heat sources is unavoidable, use MICC cable.
• Use metallic conduit or tray. Fire alarm cables should be installed in metallic conduit or on metallic cable trays throughout — not in plastic conduit, not clipped directly to the ceiling structure without protection. Metallic containment provides mechanical protection, earthing continuity, and additional fire resistance for the cable run.

Routing Through High-Risk Areas

Certain areas require special routing treatment. Kitchen areas — where cooking equipment produces high ambient temperatures — require MICC cable rather than FR-LSOH. Cable routes through fire-rated walls or floor slabs must be fire-stopped after installation. Cable routes through plant rooms, boiler rooms, or electrical switchrooms must be assessed for temperature and EMI exposure and the appropriate cable type selected accordingly.

On Saudi Aramco projects governed by SAES-B-067, cable routing in classified hazardous areas requires explosion-proof conduit systems with appropriate sealing fittings. The cable schedule must record the conduit material, rating, and sealing arrangement for every cable run through a classified area.

Separation from Power Cables

One of the most consistently violated requirements in fire alarm cable installation — and one of the most important — is the minimum separation distance between fire alarm signal cables and power distribution cables. This requirement exists for two reasons: electromagnetic interference (EMI) from power cables can induce false signals in fire alarm circuits, and proximity to power cables can expose fire alarm cables to fault currents that damage or destroy the alarm circuit.

The separation requirement must be verified at every point along the cable route — not just at the panel end or the device end. A cable that maintains 300mm separation for 95% of its run but crosses within 50mm of a power cable for 2 metres has a non-compliant installation. The cable schedule’s routing record section must document the separation check at every identified crossing or parallel run point, with the measured separation, the result, and the engineer’s sign-off.

Fire Stopping at Penetrations

Every point at which a fire alarm cable passes through a fire-rated wall, floor slab, or ceiling must be fire-stopped. This is not optional and it is not a detail that can be addressed after commissioning. Fire stopping at cable penetrations is a fundamental requirement of the building’s passive fire protection strategy — and a fire alarm cable that passes through an unsealed penetration in a fire-rated wall has created a pathway through which fire, smoke, and toxic gases can travel from one fire compartment to another, potentially faster than the fire alarm system can warn people to evacuate.

The cable schedule’s fire stopping record must document every penetration — its location referenced to the approved drawing, the cables passing through it, the size of the penetration, the fire stopping material used, the name of the person who applied it, the date, and the inspection result. This record is part of the handover documentation package and is inspected by the Civil Defence authority during the fire safety certificate process.

Approved Fire Stopping Materials

• Intumescent sealant — the most common fire stopping material for small penetrations up to 100×100mm. Applied using a sealant gun, it expands when exposed to heat to seal the annular space around the cable. Products from Hilti, STI, and 3M are widely used and hold appropriate fire resistance certifications.
• Intumescent collars — used for larger penetrations and for penetrations through floor slabs. The collar is fitted around the cable or conduit on both sides of the penetration and expands under heat to seal the opening. Required where the penetration size exceeds 50mm diameter for a single cable or conduit.
• Fire stopping pillows — used for large openings containing multiple cables. Compressed mineral wool pillows fill the void around the cables and provide both fire and smoke stopping. Must be installed to the manufacturer’s specification with the correct number of pillows per unit area.
• Mortared seals — used in structural penetrations where the architect specifies a rigid seal. The annular space is filled with fire-rated mortar after cables are installed.

All fire stopping materials must be certified to the fire resistance rating of the wall or floor they protect. A fire stopping material rated at 60 minutes must not be used in a penetration through a 90-minute fire-rated wall. The cable schedule’s fire stopping record must note the product used, its fire resistance rating, and the certification reference.

IR Testing and Continuity — The Proof of Quality

The insulation resistance (IR) test and the continuity test are the two electrical tests that verify the physical quality of every cable installation. They must be carried out on every cable — before termination and again after termination — and every test result must be recorded in the cable schedule. These tests are not optional pre-commissioning rituals. They are the documented proof that the cable installation is electrically sound.

Insulation Resistance Test

The IR test measures the resistance between the cable conductors and between each conductor and earth, using a high-voltage DC test source (typically 250VDC for 24VDC signal cables and 500VDC for 230VAC supply cables). A high insulation resistance confirms that the cable insulation is intact — there are no breaks, abrasions, or contamination points that would allow current to leak from the conductor to earth or between conductors.

Acceptance criterion: minimum 1 MΩ for all fire alarm cables. In practice, a new, correctly installed cable will typically measure hundreds or thousands of MΩ on a short run and above 100 MΩ on longer runs. A result below 1 MΩ indicates an insulation fault that must be located and rectified before the cable is commissioned. The cable schedule records the actual measured value — not just PASS or FAIL — because this baseline value is essential for future maintenance comparison.

Continuity Test

The continuity test measures the end-to-end resistance of each conductor in the cable, confirming that the conductor is intact with no breaks or high-resistance connections. For fire alarm signal cables, the total loop resistance — the combined resistance of the outward and return conductors — must not exceed the FACP manufacturer’s specified maximum for the loop or zone length. Typical acceptance criterion is 40 Ω per kilometre, or approximately 0.04 Ω per metre of conductor length.

The continuity test also verifies that terminations have been made correctly — a high-resistance reading at one end of a cable usually indicates a poor termination at a terminal block or junction box rather than a fault in the cable itself. Every continuity result is recorded in the cable schedule against the cable reference number.

When to Test

• Before termination: IR test each cable before connecting to devices or panels. This tests the cable in isolation — if the result fails, the fault is in the cable, not the termination or connected device.
• After termination: IR test again after all terminations are made. If the result is significantly lower than the pre-termination test, the fault is in the termination or in the connected device.
• Before commissioning: Final IR and continuity test across the complete installed circuit — panel to all devices and back — as part of the pre-commissioning checklist. This is the result recorded as the commissioning baseline.

Cable Labelling Requirements

Every cable in a fire alarm system must be labelled — at both ends and at every intermediate junction box, pull box, or cable tray crossing point. Cable labelling is not an aesthetic requirement. It is a functional one. An unlabelled cable in a ceiling void is indistinguishable from every other cable in that void. When a fault develops three years after installation, the maintenance engineer trying to identify which cable serves the affected detector has no means of doing so without following the cable physically — which may require dismantling ceiling tiles, scaffolding, and significant time.

The cable label must show the cable reference number as listed in the cable schedule — for example, CA-009 — which allows immediate cross-reference to the schedule’s zone, route, specification, and test results. The label must be durable — printed on a heat-shrink sleeve, a metallic tag, or a self-laminating wrap — and must remain legible for the life of the installation. Handwritten adhesive labels are not acceptable. They become illegible within months in the temperature and humidity conditions of a typical ceiling void.

The cable schedule must record that cable labelling has been completed — and the commissioning engineer must verify labels at both ends of each cable during pre-commissioning inspection. A cable with a missing or incorrect label is a documentation non-conformance that must be corrected before sign-off.

Structure of the Excel Template

Advantages of a Complete Cable Schedule

The Maintenance Value of IR Test Baselines

One of the most practically valuable functions of the cable schedule is the IR test baseline it establishes at commissioning. A new FR-LSOH cable on a typical 30-metre run will measure above 500 MΩ on its first IR test. If the annual maintenance test three years later shows the same cable measuring 15 MΩ — still above the 1 MΩ pass threshold — the maintenance engineer sees a significant degradation trend. The cable is not yet failing. But it is moving toward failure. With the baseline from the cable schedule, this trend is visible and the cable can be investigated and replaced proactively — before it fails during an alarm condition.

Without the baseline, the maintenance engineer sees 15 MΩ and records PASS. The trend is invisible. The cable continues to degrade until it fails at the worst possible time.

What Happens Without a Cable Schedule

The Cost of an Unlabelled, Unscheduled Cable Installation

Consider a fire alarm system installed without a cable schedule in a medium-sized commercial building — 150 detectors, 8 zones, approximately 80 cables. Three years after installation, Zone 04 shows a persistent fault — intermittent loss of communication with three detectors. The maintenance engineer needs to identify which cables serve those detectors, trace the fault, and replace the affected cable.

With a cable schedule: the engineer looks up the three detector addresses, identifies cables CA-031, CA-032, and CA-033, sees they all run through route CT-04, goes directly to that conduit run, tests each cable, finds the fault in CA-032 at junction box JB-04-B, and replaces the cable. Total time: four hours.

Without a cable schedule: the engineer opens ceiling tiles at each detector, physically traces the cables backward toward the panel, trying to identify which of the dozens of cables in each void is the correct one. Three days later, having traced the route through four ceiling voids and two junction boxes, the fault is found. Total time: three days.

The cable schedule paid for the time to prepare it many times over in the first maintenance call.

Standards Alignment

NFPA 72 — National Fire Alarm and Signaling Code

NFPA 72 Chapter 12 addresses wiring methods and equipment for fire alarm systems. It requires that all wiring be installed in a neat and workmanlike manner and comply with applicable installation requirements. Specific requirements include: fire alarm cables must be supported independently of the building’s structural system; conductors must be protected from physical damage; and cables in the same raceway must be fire alarm system conductors only — no mixing with general wiring. The 300mm separation requirement from power conductors is specifically addressed in Clause 12.3.1.

BS 5839 Part 1 — Code of Practice

BS 5839 Part 1 Section 26 addresses the installation of fire alarm cables in detail. It requires fire-resistant cables throughout, specifies that cable routes should be as short as practical and not pass unnecessarily through fire-risk areas, defines the 300mm minimum separation from power cables, and requires that all cable penetrations through fire compartment boundaries be fire-stopped. The standard also requires that a record of all installed cables be kept — this record is the cable schedule.

IEC 60331 — Fire Resistant Cable Performance

IEC 60331 defines the test methods and performance requirements for cables intended to maintain circuit integrity under fire conditions. IEC 60331-25 covers cables with cross-sectional areas up to 300mm² tested at 750°C for 90 minutes. When specifying fire alarm cables, the product must hold a valid IEC 60331 certificate appropriate to the fire performance requirement. The cable schedule should record the IEC 60331 part and the fire resistance duration for every cable type specified.

SAES-B-067 — Saudi Aramco Fire Protection

SAES-B-067 governs fire protection systems on Saudi Aramco facilities and projects. For fire alarm cables on Aramco sites, the standard requires fire-resistant cable throughout, metallic conduit protection in process areas and hazardous locations, specific cable types in classified areas, and complete documentation of all cable installations including IR test records. The cable schedule submitted to Saudi Aramco must be comprehensive, signed by the contractor’s engineer, and cross-referenced to the approved fire alarm drawing set.

Conclusion

The fire alarm cable schedule is the foundational technical document of every fire alarm installation. It begins during design — as the cable selection and routing decisions are made — and it grows through installation, testing, and commissioning to become the complete, verified record of how the system’s nervous system was built. At handover, it is the document that proves the installation was done correctly. Throughout the building’s operational life, it is the reference that makes maintenance faster, fault diagnosis more accurate, and system reliability higher.

Getting the cable selection right — FR-LSOH for standard circuits, MICC for high-temperature routes, and never PVC — protects the system’s ability to function during the emergency it was built to manage. Getting the routing right — separation maintained, conduit protected, bending radii respected — ensures the cable reaches the end of its designed life without premature failure. Getting the testing right — IR tests recorded at baseline with actual values, continuity confirmed at every circuit — provides the maintenance baseline that makes the difference between a system that degrades silently and one that is maintained proactively.

Download the free Excel template, adapt it to your project, fill in every cable from day one of installation, and hand over a document that demonstrates your quality and technical capability — one cable reference at a time.