Electrical fire safety in the home

How electrical fires usually start

The most common mechanism is heat at a poor connection. A loose terminal in a socket, a worn plug pin, a damaged flex or an over tightened screw creates resistance, resistance creates heat, and heat over months degrades the surrounding plastic until it ignites. This is why a socket that is warm to the touch is a warning rather than a curiosity.

The second mechanism is overload, most often through extension leads and multi way adaptors. A four way lead is typically rated at 13A total, and plugging a heater, a kettle and an iron into one exceeds that quickly. A coiled cable reel is worse still, because the coil traps heat in the cable.

The third is appliance failure, particularly appliances with heating elements and motors: tumble dryers, washing machines, dishwashers and, increasingly, lithium battery chargers for e bikes and scooters.

• Loose or deteriorating connections generating heat over time
• Overloaded extension leads and coiled reels
• Damaged flexes, particularly where they pass under doors or furniture
• Appliances running unattended overnight or while out
• Cheap or counterfeit chargers and lithium battery packs

Warning signs to act on

Scorch or brown marks around a socket, a plug that is hot to the touch, a persistent smell of hot plastic, buzzing or crackling from an accessory or the board, lights dimming when a heavy appliance starts, and breakers that trip repeatedly are all signals that something is generating heat or leaking current where it should not.

None of these are things to live with. Isolate the circuit, stop using the accessory and get it inspected. A socket that has been quietly running warm for a year is a fire that has not happened yet.

Extension leads, chargers and habits

Use one four way lead per socket rather than plugging one into another. Never run a heater, kettle or iron from a lead shared with other high load items. Uncoil cable reels fully before use. Keep leads out from under rugs and away from door thresholds where they are crushed repeatedly.

For lithium batteries, e bikes and scooters especially, use the manufacturer's charger, charge on a hard surface away from escape routes, and do not charge overnight or while out. Fires from these batteries develop extremely quickly and are extremely difficult to extinguish, which is why fire services have become so vocal about them.

• One adaptor per socket, never daisy chained
• Uncoil cable reels completely before drawing load
• Charge lithium batteries away from hallways and stairs
• Do not run washing machines or dryers overnight
• Replace damaged flexes rather than taping them

Alarms and detection in Wales

Smoke alarms are the difference between a fire you escape and one you do not. Requirements for rented homes in Wales are now specific: properties must have interlinked mains powered smoke alarms on every storey and a carbon monoxide alarm in every room with a fuel burning appliance. Interlinked matters, because an alarm sounding in a kitchen you cannot hear from a bedroom is worth very little at three in the morning.

Even where you are an owner occupier and not covered by those duties, the same specification is the right one to fit. Test them monthly, replace the units at the end of their stated life rather than when they fail, and never remove a battery to stop nuisance alarms.

The checks that reduce risk most

Three things do most of the work. RCD protection, which disconnects earth leakage faults in milliseconds and did not exist in older boards. A periodic inspection, which finds the loose connections and deteriorating cable you cannot see. And replacing failing accessories rather than living with them.

For a typical owner occupied home, an EICR every ten years is the usual recommendation, sooner on an older installation with no test history or after buying. For rented property in England and Wales it is at least every five years. Between inspections, a visual walk round every few months costs nothing: look for cracked accessories, warm plugs, brown marks and damaged flexes.