An intruder alarm system relies entirely on a continuous, stable supply of electrical power. While systems plug directly into your property’s standard mains electricity, relying solely on grid power introduces a significant vulnerability.
If a localised power cut blacks out a street, or if an intruder cuts the incoming electrical wires to your building, a system without specialised power resilience will shut down immediately, leaving the property unprotected.
To prevent these vulnerabilities, British and European security standards (PD 6662 and EN 50131) mandate that all professional control panels include an engineered standby battery backup system. Understanding how these backup power systems operate is essential for maintaining a secure perimeter.
The Statutory Operational Run-Time Requirements
The National Security Inspectorate (NSI) enforces strict rules regarding how long an intruder alarm must remain fully operational following a total loss of mains power. These standby requirements change based on the risk grade of your system:
- Grade 2 (Standard Residential): The internal standby battery must keep the entire system, including all connected motion sensors, keypads, and communication links, fully operational for a minimum of 12 hours during a power outage.
- Grade 3 (High-Risk Commercial): If the system does not feature an auxiliary standby generator, the internal backup infrastructure must power the system for at least 24 hours, ensuring continuous monitoring over weekends or holiday closures.
The Technical Risks of Degraded Battery Cells
Standby batteries are specialised, sealed lead-acid (SLA) or lithium-ion cells housed inside the main, tamper-protected steel control panel. These cells are kept under constant charge by the system’s power supply unit. However, like all rechargeable batteries, they experience chemical degradation over time.
If a backup battery is left unserviced for more than three to four years, its power storage capacity drops significantly. If a power cut then occurs, the voltage will quickly fall below the system’s operational threshold.
This asset drop can cause the panel’s microprocessor to crash, generating immediate false alarms from the external siren box (SAB), which uses its own internal battery to sound a warning if it detects a control panel failure. This creates a noisy disruption that can lead to council noise fines.
The Necessity of Professional Load Testing
A basic battery voltage check with a standard multimeter can be misleading, as a degraded battery can still show a normal voltage reading when sitting idle.
To determine a cell’s true condition, an NSI Gold-certified technician performs a formal dynamic load test during your annual scheduled maintenance visit. The engineer applies a temporary, high-amp current draw to the battery to measure its voltage stability under active operational stress.
If the cell shows signs of capacity loss, it is replaced with a certified, fresh cell. This simple check protects your home or business from unexpected system blackouts and ensures your commercial insurance policy remains fully valid.
Ensure your property remains protected during a power outage
Don’t wait for a local blackout to reveal a degraded backup battery cell. Contact the experts at Clear Sound Fire & Security to find out more about our intruder alarm maintenance services.
