Mains-Wired Smoke & Heat Alarms for Homes

Smoke alarms give the early warning that lets people get out of a house safely. A mains-wired, interlinked system is more dependable than a scatter of battery alarms, because it doesn't go quiet when a battery runs flat and every alarm sounds together. This page covers our domestic alarm installations for homeowners and landlords.

How a mains alarm system works

Each alarm is fixed to the ceiling on a base wired back to a circuit in the house. Inside is a back-up battery, often a sealed cell rated for the life of the alarm, which keeps it working during a power cut. The alarms are linked together, either with an extra interconnecting wire or by radio, so detection anywhere triggers sounders everywhere. Most systems also allow a test or hush button on one alarm to control the rest.

Smoke alarms and heat alarms

Smoke alarms suit hallways, landings and living areas. They come in optical and ionisation types, with optical alarms widely used in homes because they respond well to slow, smouldering fires. Kitchens are different: everyday cooking would set off a smoke alarm, so a heat alarm is used instead. It triggers on a fast rise in temperature and is linked into the same system, so a kitchen fire still raises the alarm upstairs.

Where alarms usually go

In general terms, there should be a smoke alarm in the circulation space on every storey, such as the hall and each landing, with a heat alarm in the kitchen. Larger homes, open-plan layouts and loft conversions often need more, and some households add alarms to the main living room or bedrooms. Alarms sit on the ceiling, away from walls, light fittings and corners where air doesn't move. We look at the layout and suggest positions before quoting.

Rules for landlords in England

Private landlords in England have legal duties on smoke and carbon monoxide alarms, including at least one smoke alarm on each storey used as living accommodation, and checks that alarms are working at the start of each new tenancy. The detailed requirements are set by government and can change, so check the current guidance on gov.uk. Many landlords choose mains interlinked alarms because they are lower maintenance between tenancies.

Adding alarms during other work

The best time to fit mains alarms is during a rewire or refurbishment, when cables can be run in ceiling voids without disturbing finished decoration. In an occupied home we route cables as neatly as the building allows, using loft space and existing voids, and agree any surface trunking with you first. Radio-interlinked alarms can reduce the cabling needed between floors.

Which circuit they use

Mains alarms are commonly supplied from a regularly used lighting circuit or from their own dedicated circuit, depending on the installation and current guidance. If the board is old, has rewireable fuses or lacks RCD protection, we may recommend a consumer unit upgrade first, and we explain why before any extra work is agreed.

Looking after your alarms

Press the test button regularly, keep alarms free of dust and paint, and never remove the battery or cover them during decorating without putting them back straight away. Alarms have a replacement date printed on them. If one chirps, sounds without reason or shows a fault light, check the manufacturer's leaflet and call us if you can't resolve it.

What we don't do

We install domestic mains smoke and heat alarms only. We don't design, install or test commercial fire alarm systems, which are a separate specialist field. Carbon monoxide alarms for gas appliances can sometimes be added to an interlinked system; ask when you get in touch.

Book a visit

Adtec Electrical Services Ltd works from Lyford Business Centre near Wantage. Call 01235 430442, Monday to Friday, 7:30am to 5:30pm, or send the form with the number of storeys and rooms. See the areas we cover.