Fire alarm systems range from simple conventional zone panels to sophisticated analogue addressable networks. Understanding the differences — and when to specify each type — is essential for electricians working on commercial installations, HMOs, and larger residential developments. This guide covers every system type, BS 5839 categories, and practical wiring requirements.
Free for 7 days · No charge until day 8 · Cancel anytime · Used by 1,000+ UK electricians
Written and reviewed by Andrew Moore, founder of Elec-Mate, against BS 7671:2018+A4:2026, IET Guidance Note 3 and the IET On-Site Guide.
1,000+
UK electricians
“Replaced three separate apps with Elec-Mate. Certs, quotes, and scheduling all in one place.”
Daniel Palmer — DP Electrical
Before selecting the system type, the category of the fire alarm system must be determined. BS 5839-1 (for non-domestic premises) and BS 5839-6 (for domestic premises) define the categories that specify the purpose and extent of fire detection and alarm coverage.
Manual call points (break glass units) only — no automatic detection. Relies on occupants discovering the fire and activating the nearest call point. Typically specified for buildings where the fire risk assessment does not require automatic detection, or as a minimum baseline for simple commercial premises.
L1 — Detection throughout all areas of the building. L2 — Detection in escape routes and rooms opening onto escape routes, plus high-risk areas. L3 — Detection in escape routes only. L4 — Detection within escape routes forming part of the means of escape only. L5 — Detection in specific areas as determined by the fire risk assessment. L2 and L3 are the most commonly specified categories for commercial premises and HMOs.
P1 — Detection throughout all areas to provide the earliest possible warning for property protection purposes. P2 — Detection only in specified areas of high risk. P categories are typically specified by insurers or for unoccupied premises where fire damage must be minimised.
The category determines how many detectors are needed and where they must be placed, but it does not dictate whether the system should be conventional, addressable, or analogue addressable. That decision depends on the building size, layout, and operational requirements.
Every key change in the 2026 amendment on one page. AFDDs, TN-C-S protection, new schedule columns, model forms. Pinned on your van dash.
A conventional fire alarm system divides the building into zones, with each zone wired as a separate circuit back to the fire alarm panel. All detectors and call points within a zone are connected to the same pair of wires. When any device in the zone activates, the panel identifies which zone is in alarm but cannot identify the specific device.
Conventional systems are cost-effective for smaller buildings with clearly defined areas — a small office, a shop, a restaurant, or a domestic HMO. The panels are simpler, the devices are less expensive, and the wiring is straightforward. However, in larger buildings, the number of separate zone cables running back to the panel becomes impractical.
An addressable fire alarm system connects all devices — detectors, call points, sounders, and modules — on a single loop circuit. Each device is programmed with a unique address (typically a number from 1 to 126 or 1 to 250, depending on the panel). When a device activates, the panel identifies the exact device by its address and displays a text description (e.g., "Smoke Detector — Room 204, Second Floor").
The loop starts at the panel, runs through every device on the loop, and returns to the panel — forming a complete circuit. This provides inherent resilience: if the loop cable is broken at any point, the panel can still communicate with all devices by addressing them from both ends of the broken loop. This is a significant advantage over conventional radial circuits, which lose all devices beyond the break point.
The panel continuously polls each device on the loop, checking its status and confirming communication. When a detector activates, the panel immediately knows which device has triggered and displays its programmed text label. This allows the responding person to go directly to the device rather than searching an entire zone. In a large building, this can save minutes — which is critical in a fire.
Because all devices share a single loop, the total cable requirement is significantly less than a conventional system with separate zone circuits. A building that might need 20 conventional zone circuits (20 separate cable runs back to the panel) can be served by a single addressable loop. This reduces installation cost and time, particularly in large or complex buildings.
Elec-Mate's digital fire alarm certificate captures all system details, zone or loop information, device locations, and commissioning test results.
Try it free for 7 days
Analogue addressable systems represent the most advanced level of fire detection technology commonly used in commercial buildings. Unlike standard addressable systems (which report a simple "alarm" or "normal" status), analogue addressable devices continuously report their environmental readings to the panel — the actual smoke density, temperature, or CO level at each device.
Analogue addressable systems are standard for hospitals, schools, universities, office buildings, hotels, and any building where false alarm reduction and rapid fire location are priorities. The initial cost is higher than standard addressable or conventional systems, but the reduced false alarm rate and lower ongoing maintenance costs typically justify the investment for larger installations.
16 certificate types, 70+ calculators, RAMS, quoting, invoicing, AI agents, and 46+ training courses — from £6.99/mo.
Start free trialHybrid fire alarm panels accept both conventional zone circuits and addressable loop circuits. This makes them valuable in several scenarios:
When upgrading an existing conventional system, a hybrid panel allows the existing conventional zone wiring to be retained while new areas are added on addressable loops. This avoids the cost and disruption of rewiring the entire building at once. Over time, conventional zones can be migrated to the addressable loop as budgets allow or when the conventional wiring reaches end-of-life.
Buildings with both simple areas (corridors, stores) and complex areas (offices, server rooms) may benefit from conventional coverage in the simple zones and addressable coverage in the complex areas. This optimises cost without compromising detection capability where it matters most.
Where the budget does not stretch to a full addressable system, a hybrid approach provides addressable identification in critical areas while using less expensive conventional devices elsewhere. The total system cost falls between a fully conventional and fully addressable installation.
The choice between conventional, addressable, and analogue addressable depends on the building size, complexity, budget, and the requirements of the fire risk assessment.
Up to 4-6 zones, single floor or small multi-storey
10-50 devices, multi-storey, multiple occupancy
50+ devices, complex layout, false alarm critical
Budget for partial upgrade, mixed old/new areas
Always check the fire alarm certificate requirements for the specific building type. The fire risk assessment should specify the required category (L1, L2, L3, etc.) and any specific detection requirements. If in doubt, consult with a fire alarm specialist or the fire risk assessor.
Fire alarm wiring has specific requirements that differ from standard mains wiring. The cable must maintain circuit integrity during a fire for long enough to raise the alarm and allow evacuation.
BS 5839-1 requires fire alarm cables to be fire resistant to BS 7629 or BS 8434. Standard PVC cable (6242Y twin-and-earth) must not be used for fire alarm circuits. The most common fire alarm cable is enhanced fire resistant cable (often branded as FP200 or Firetuf), which maintains circuit integrity at temperatures up to 950°C for at least 2 hours. This ensures the system continues to operate during the fire.
Fire alarm cables must be segregated from mains power cables to prevent interference and ensure the alarm circuit is not compromised by a fault on the mains wiring. BS 5839-1 recommends a minimum separation of 300mm from mains cables, or the use of separate conduit or trunking. Where fire alarm cables cross mains cables, they should do so at right angles.
Addressable loop circuits typically use 2-core fire resistant cable (1.0mm² or 1.5mm²). The loop must start and return to the panel — never terminate at a device. Some panels support Class A (loop returns to panel) and Class B (radial — does not return) loop configurations. Class A provides the highest resilience and is the standard for most commercial installations. The testing sequence for fire alarm circuits includes loop resistance, insulation resistance, and earth fault checks.
Fire alarm systems are often installed alongside emergency lighting. Elec-Mate's emergency lighting certificate form covers all BS 5266 requirements —…
Try it free for 7 daysA practical guide to installing a networked fire alarm system.
Obtain the fire risk assessment for the building. Identify the required BS 5839 category (M, L1-L5, P1-P2). Determine the detection type required for each area (smoke, heat, multi-sensor, CO). Assess the building layout and decide whether conventional, addressable, or analogue addressable is appropriate.
Plan detector locations to ensure compliance with the specified category. Design zone boundaries (conventional) or loop routing (addressable). Position manual call points at exits. Plan sounder locations to achieve the required sound level (65dB or 75dB at bedhead). Identify power supply and battery backup requirements.
Run fire resistant cable (FP200 or equivalent) for all fire alarm circuits. Install detectors, call points, sounders, and interface modules. Maintain correct segregation from mains cables. Install the fire alarm panel in a suitable location (typically the main entrance for fire service access).
Programme device addresses (addressable systems). Test every detector using approved test equipment (smoke aerosol, heat test lamps). Verify every call point operates correctly. Check sounder levels meet BS 5839 requirements throughout the building. Test battery backup and mains failure switchover.
Complete the commissioning certificate with all test results and system details. Prepare the system logbook. Issue the as-fitted drawings showing device locations and cable routes. Hand over to the responsible person with operating instructions and maintenance schedules.
Verified reviews from the UK App Store.
Elec-Mate is my go to app for business and electrical work. It's feature rich without feeling cluttered. A true all in one app for quotes, certs, calculations, RAMS, EICRs, and more. I use it every day without fail, and it makes my workflow much smoother since I'm not jumping between apps anymore. The price-to-feature ratio is excellent. Any issues I've had, the developer responds within the hour and usually fixes them the same day. 100% recommend.
I've used the app and the web based version for a while now and it's well worth the investment. If you're an apprentice or experienced Spark give it a go, you won't be disappointed.
I've been using Elec-Mate for a while now, and honestly, it's one of the best apps I've ever downloaded. Every aspect of it feels thoughtfully designed, from the clean and intuitive interface to the powerful features that make everything so easy to manage. It's clear that a lot of care and attention went into building this app, and it shows in every detail.
Real feedback from real sparks
“Replaced three separate apps with Elec-Mate. Certs, quotes, and scheduling all in one place.”
Daniel Palmer
Sole Trader · DP Electrical
“I've won two contracts this month because I could turn quotes around same-day with the AI cost engineer.”
Nathan Perry
Electrician · NP Electrical Services
“The study centre got me through my AM2. Mock exams and flashcards are brilliant.”
Jake Pizey
3rd Year Apprentice · Apprentice
Digital fire alarm certificates, emergency lighting forms, and EICR documentation — all validated against BS 5839 and BS 5266. 7-day free trial, cancel anytime.
“Replaced three separate apps with Elec-Mate. Certs, quotes, and scheduling all in one place.”
Daniel Palmer, DP Electrical
From £6.99/mo after trial — less than a coffee a week
We use cookies to improve the app and measure what works. Cookie Policy