Portable generator: how to use it safely during a power cut

Keep the power outside — and the exhaust well away from everyone.

The answer in 2 lines. A fuel-powered generator produces carbon monoxide: a poisonous gas you cannot see or smell. Run it outdoors, away from doors, windows and air vents, including your neighbours'. Never run it in a garage, shed, conservatory or other enclosed space, even with the doors open. Use only the appliance connections permitted by its instructions; never plug its output into a household wall socket. Connecting it to your home's wiring needs a qualified electrician. If you suspect carbon monoxide exposure, get outside and seek medical advice.

The first steps

Read the instructions before starting. Check the permitted location, weather protection, electrical connections and load.
Choose an open-air position. Keep exhaust away from your home and neighbouring doors, windows and vents.
Use suitable appliance leads. Keep connections dry and follow the generator's electrical protection requirements.
Switch off and let it cool before refuelling. Keep fuel outside living areas in suitable labelled containers.

Stop: danger

Generator running indoors or in a partly enclosed space: do not stay there. Get everyone outside; only stop the engine if you can do so without exposing yourself.
Possible carbon monoxide symptoms: headache, dizziness or nausea can be warning signs. Go outside, stay out of the affected building and call NHS 111 for urgent advice.
Exposure with breathing difficulty, sudden confusion, unconsciousness, weakness, or chest or muscle pain: call 999. Do not drive yourself to hospital.
Smoke or fire: leave the area and call 999. Do not attempt to move a burning generator.

Choose the position before the power fails

A garage with its door open is still an unsafe place to run a generator. The same applies to a cellar, shed, porch or conservatory. Outdoors, exhaust can still enter through openings: consider neighbouring homes as well as your own.

Follow the manufacturer's clearance and weather-protection instructions. Do not improvise a cover that traps exhaust or heat. If your available space cannot meet the instructions, do not run the generator there. An indoor carbon monoxide alarm adds protection but cannot make an unsafe location safe.

Connect appliances without improvising

Use only suitable heavy-duty leads and the connections allowed by the instructions. Check for damaged insulation and keep plugs out of rain and standing water. Do not overload the generator: its permitted load and an appliance's starting requirements both matter.

Earthing and residual current device protection depend on the generator and equipment. Do not assume that having spare sockets means you can safely connect several appliances. The HSE electrical safety guide, under 'Generators', explains why these arrangements need competent assessment. It concerns construction sites; use it to understand the hazards, not as a domestic installation manual. Ask a qualified electrician if your instructions leave anything unclear.

What not to do

Testing the engine inside the garage, even briefly.
Putting the exhaust beneath a window or beside a neighbour's door.
Feeding electricity into a household socket, including through a lead with exposed plug pins.
Refuelling while the engine is running or hot.
Assuming a carbon monoxide alarm replaces safe positioning.

Fuel, household wiring and medical equipment

Keep fuel away from ignition sources and living areas. Refuel outside with the engine stopped and cooled. The HSE petrol safety guidance explains suitable storage and containers: check it before storing petrol at home.

A connection to fixed household wiring requires a qualified electrician to design safe isolation from the public supply and suitable protection. Do not make a temporary connection yourself.

If someone depends on powered medical equipment, arrange a backup plan with their care team and equipment provider before an outage. Do not assume a portable generator is suitable for that equipment.

Help during a power cut in England

Call 105 to reach your local electricity network operator and report the outage. The Dorset & Wiltshire Fire and Rescue Service power-cut advice explains this route and preparations such as charging essential devices and keeping torches ready.

For symptoms and the right medical response, use the NHS carbon monoxide page: follow its urgent and emergency advice. The safety principles also apply elsewhere in the UK, but local outage and healthcare arrangements can differ.

Good to know

Review the generator's instructions before each use, especially if you borrowed it.
Check your carbon monoxide alarm using its test procedure and follow its placement instructions.
When mains power returns, follow the generator's shutdown instructions before reconnecting appliances to household sockets.

Illustrative example: during an outage near York, Helen considers running a borrowed generator in her open garage. She checks the instructions and instead chooses a suitable outdoor position away from openings. When the proposed appliance connections are unclear, she waits for qualified advice rather than adding an extension block.

A made-up story, for illustration.

Bobby

Sources, verification, confidence

Verified on 4 November 2026, for England. Confidence: high for carbon monoxide precautions, medical escalation and power-cut reporting; medium for individual electrical arrangements, which require the manufacturer's instructions and competent assessment. Northern Ireland's public safety guidance supports general generator precautions; it is not presented as English law. No universal clearance distance is specified.