Power cuts are disruptive, inconvenient, and, in certain situations, dangerous. In homes, offices, and rental properties across London, emergency lighting provides a vital safeguard during unexpected blackouts or failures of the main electrical supply. But an important question arises: how long should emergency lights stay on during a power cut?
The answer is not simply about preference but about safety, compliance, and regulation. In the UK, specific standards dictate how long emergency lighting systems must operate after the power supply fails. These durations are carefully designed to allow occupants enough time to safely evacuate buildings without panic, confusion, or unnecessary risk.
At RCD Electrical, we specialise in installing and maintaining emergency lighting systems that fully comply with British safety standards. From landlords of multi-occupancy houses to managers of high-rise apartment blocks, we ensure properties are equipped with reliable systems that perform exactly as required when the unexpected happens.
Call: 02034882928
Email: info@rcdelectrician.co.uk
Website: rcdelectrician.co.uk
Why Duration Matters in Emergency Lighting
The Role of Emergency Lighting
Emergency lighting is not about comfort—it is about survival. When the power cuts out, these lights guide people safely towards exits and assembly points.
Consequences of Insufficient Duration
If emergency lights fade too quickly:
-
Occupants may become trapped in darkness.
-
Evacuation routes may become hazardous.
-
Injuries and accidents are more likely.
-
Landlords and property managers may face liability claims.
The Standards Governing Emergency Lighting
British Standards (BS 5266)
The key document for emergency lighting is BS 5266-1, which outlines design, installation, and maintenance requirements. According to this code, most emergency lighting systems must provide illumination for at least three hours after a power failure.
Wiring Regulations (BS 7671)
BS 7671 ensures that all emergency systems are wired safely and reliably. At RCD Electrical, our installations always adhere to these rules.
Fire Safety Order 2005
Under the Regulatory Reform (Fire Safety) Order 2005, landlords and building managers are considered “responsible persons” for ensuring safe evacuation procedures, including providing adequate emergency lighting.
Typical Duration of Emergency Lighting
One-Hour Systems
Some emergency lights are designed to last a minimum of one hour, which is suitable for smaller buildings where evacuation can be achieved quickly.
Three-Hour Systems
The most common standard is three hours. This ensures that:
-
Occupants can evacuate safely.
-
Firefighters can navigate the building if required.
-
Properties remain safe during prolonged outages.
Why RCD Electrical Recommends Three Hours
Although one-hour systems are legal in certain cases, at RCD Electrical we strongly recommend three-hour systems. They provide maximum reassurance for tenants, landlords, and authorities alike.
Factors That Affect Emergency Light Duration
Battery Technology
-
Nickel-cadmium (NiCd): Reliable but less efficient.
-
Nickel-metal hydride (NiMH): Longer-lasting and more eco-friendly.
-
Lithium-ion: Increasingly common due to high performance and compact size.
Testing and Maintenance
Even the best system will fail if not maintained. Batteries degrade over time, so regular testing is essential to confirm that lights still last the required duration.
Environmental Conditions
Heat, dampness, and poor ventilation can reduce battery lifespan. RCD Electrical ensures installations are properly protected against such issues.
How RCD Electrical Ensures Compliance
Installation of Compliant Systems
We design and install systems tailored to each property, ensuring they meet the exact standards required for the building’s type and usage.
Routine Testing and Certification
We carry out:
-
Monthly functional tests.
-
Annual full-duration tests (up to three hours).
-
Issue compliance certificates for landlord records.
Upgrading Old Systems
If your property has outdated one-hour lights or failing batteries, RCD Electrical can upgrade you to modern three-hour LED emergency lighting systems.
Benefits of Partnering with RCD Electrical
Local Knowledge of London Properties
From Edwardian conversions to modern apartments, we understand the diverse needs of London buildings.
Energy-Efficient Technology
We install LED-based emergency lights that consume minimal energy while providing maximum duration.
24/7 Support
Our electricians are available at any time to deal with emergency lighting faults or unexpected failures.
Case Studies in London
Hackney HMO Upgrade
A landlord contacted RCD Electrical after discovering their one-hour emergency lights failed council inspection. We replaced the system with a modern three-hour solution, securing compliance and safety.
Canary Wharf High-Rise
We provided full-duration testing in a large apartment block. When several units failed to reach three hours, our team replaced batteries and ensured full compliance within days.
Kensington Boutique Hotel
Emergency lighting in guest corridors was upgraded to lithium-ion powered units with three-hour duration, ensuring safety and peace of mind for both guests and staff.
Common Myths About Emergency Light Duration
“One Hour Is Always Enough”
This is not true for most London rental properties. Three hours is the standard and safest option.
“LED Lights Don’t Need Testing”
Even LED-based systems rely on batteries, which must be tested and replaced when necessary.
“My System Is New, So It Doesn’t Need Checks”
New systems can still fail without routine inspection and proper maintenance.
The Dangers of Non-Compliance
Landlords or managers who fail to provide adequate duration emergency lighting risk:
-
Fines and enforcement from councils.
-
Prosecution under fire safety law.
-
Voided insurance policies.
-
Legal claims from tenants or visitors in case of injury.
How Long Should They Last in Real-Life Situations?
Residential Properties
Three hours is the safest choice for HMOs, blocks of flats, and converted properties.
Commercial Buildings
Shops, offices, and warehouses typically require three hours to ensure safe evacuation and fire service access.
Healthcare Settings
Hospitals and care homes may need customised systems with extended duration to protect vulnerable occupants.
RCD Electrical’s Step-by-Step Service
-
Initial survey – Assess property requirements.
-
Design proposal – Recommend the correct system.
-
Installation – Carried out by qualified electricians.
-
Testing – Monthly and annual checks.
-
Certification – Full compliance reports issued.
-
Ongoing maintenance – Regular battery replacement and monitoring.
Call today: 02034882928
Email: info@rcdelectrician.co.uk
Website: rcdelectrician.co.uk
Conclusion
So, how long should emergency lights stay on during a power cut?
The answer depends on the property, but for most London landlords and property managers, the standard is three hours. This duration ensures safe evacuation, compliance with law, and peace of mind for everyone involved.
At RCD Electrical, we provide expert installation, thorough testing, and ongoing support to guarantee your emergency lighting performs exactly as it should. With our help, you can avoid legal risks and keep your tenants safe no matter what.