The short answer
A generator can help in a long power cut, but it makes carbon monoxide, which can kill. Run it outdoors only, at least 6 metres (20 feet) from the house with the exhaust pointing away from doors and windows, and never in a garage, shed, porch or tent. Plug appliances straight into it with heavy-duty leads; don't connect it to your house wiring, because that can send power back down the lines. Store fuel outside your living space, refuel only when it's off and cool, and fit battery carbon monoxide alarms indoors. For phones, lights and a router, a battery power station is often simpler and makes no fumes.
Carbon monoxide warning. Petrol and diesel generators make carbon monoxide (CO), a poisonous gas you can't see or smell. It can kill. Never run a generator indoors, or in a garage, shed, porch, conservatory or tent, even with the door open. Keep it outdoors at least 6 metres (20 feet) from the house, with the exhaust pointing away from doors and windows (UK Chief Medical Officers). Fit battery carbon monoxide alarms inside. If anyone feels dizzy, sick or has a headache, get everyone outside and call 111, or 999 if someone is struggling to breathe, confused or collapses (NHS).
Do you need a generator at all?
A generator isn't on the GOV.UK Be Ready kit list. Be Ready asks for a torch, a battery or wind-up radio and a charged power bank. For most homes, that covers a power cut of a day or two.
A generator may make sense if you get long power cuts, live somewhere remote, or need to run something big, such as a freezer, for many hours. Even then, ask whether a battery power station would do the job: it makes no fumes, is quiet and can be used indoors. Our power station size guide and runtime calculator help you check.
If someone at home relies on powered medical equipment, join the Priority Services Register with your electricity supplier and your network operator. Ofgem says members get priority support in an emergency and, wherever possible, advance notice of planned power cuts.
Where to put it
- Outdoors only, at least 6 metres (20 feet) from the house, exhaust facing away from windows and doors (CMOs).
- Never in a garage or other partly enclosed space, even with ventilation. Don't run it near open doors or windows: fans won't stop CO building up (HSENI).
- Keep it out of rain and standing water (HSENI).
- Never leave it running unattended, and keep a fire extinguisher nearby (CMOs).
How to connect things: the backfeed danger
Plug appliances straight into the generator using heavy-duty extension leads, and don't go over the wattage limit in the manual (HSENI).
Never connect a generator to your house wiring by plugging it into a wall socket or the fuse board. HSENI warns this could cause a surge that may cause injury or death. Power can also flow back out of your house onto the network, where engineers working on the lines may not expect it. This is called backfeed.
The only safe way to run house circuits from a generator is a changeover switch fitted by a qualified electrician, which physically cuts your home off from the grid first. Ireland's network operator, ESB Networks, says exactly this: the premises must be physically isolated, using a changeover switch and changes to the wiring, and it points people to a registered electrician.
Fuel: storing and refuelling
HSE's rules for storing petrol at home:
- Up to 30 litres with no need to tell anyone.
- In suitable containers: plastic up to 10 litres each, metal up to 20 litres each, or one demountable tank up to 30 litres.
- Not in your living accommodation. If the store isn't in the open air, it needs a direct exit to the open air and ventilation. Keep it away from heat and anything that could light it.
- More than 30 litres (up to 275) means you must notify your local Petroleum Enforcement Authority.
HSENI adds: keep fuel in labelled, sealed containers away from gas stoves and other fuel-burning appliances. Switch the generator off and let it cool before refuelling: spilt fuel on hot parts can catch fire.
Signs of carbon monoxide poisoning
The NHS lists headache, dizziness, feeling sick, weakness, tiredness, confusion, chest and muscle pain and shortness of breath. Symptoms often ease when you go outside. Turn off the generator if it's safe, get everyone outdoors and get medical advice. Call 999 if someone is struggling to breathe, confused or collapses.
Where official sourcing is weak
- UK guidance on connecting generators to homes is thin. The clearest UK line we found is HSENI's (Northern Ireland): don't connect a generator to your home's wiring. We found no GOV.UK or Great Britain network-operator page on changeover switches, so the changeover-switch detail comes from ESB Networks in Ireland. Ask a registered electrician before any work.
- HSE's petrol rules don't say whether they apply in Scotland and Northern Ireland. Check with your local Petroleum Enforcement Authority.
- We couldn't open Electrical Safety First's advice on generators, so it isn't cited.
What to buy
About these links: plain links to ordinary retailer pages. We may earn from some links in future; we don't now. We haven’t tested these and we don’t rank them: they are examples that were in stock when we checked. Prices change. Check what you already own first. Full kit list
Carbon monoxide alarm
Look for: A loud alarm in each room with something that burns gas, oil, coal or wood. Battery powered, so it keeps working in a power cut. A portable one can go with you into the room you use.
- FireAngel FA6813 Portable Carbon Monoxide Alarm 10 Year · Amazon UK · £13.98 (price on 1 November 2026) Shop
- FireAngel FA3820 Portable Carbon Monoxide Alarm 10 Year Battery · Amazon UK · £22.00 (price on 1 November 2026) Shop
- Carbon Monoxide Detector & Alarm Portable Battery Powered (EN50291-1:2010) · EVAQ8 · £22.74 (price on 1 November 2026) Shop
Portable power station (optional, bigger budget)
Look for: Check the capacity in watt-hours (Wh) and the continuous AC output in watts against what you want to run. Our runtime calculator does the sums.
- Jackery Explorer 300D Portable Power Station · Jackery UK (brand store) · £219.00 (price on 1 November 2026) Shop
- EcoFlow RIVER 2 MAX 512Wh LiFePO4 · Amazon UK · £449.00 (price on 1 November 2026) Shop
- Jackery Explorer 1000 Plus v2 Portable Power Station · Jackery UK (brand store) · £599.00 (price on 1 November 2026) Shop
- Jackery Explorer 1000 v2 1070Wh LiFePO4 · Amazon UK · £469.00 (price on 1 November 2026) Shop
Frequently asked questions
Should I get a generator for power cuts?
Only if you can run it safely outdoors, store fuel properly and you need more power than a battery can give. A generator isn't on the GOV.UK Be Ready kit list. For phones, lights, a router or a small medical device, a battery power station is quieter, makes no fumes and can be used indoors.
Can I run a generator in the garage with the door open?
No. HSENI says never run one indoors or in partly enclosed spaces such as garages, even with ventilation, and not near open doors or windows: fans won't stop carbon monoxide building up. The UK Chief Medical Officers say place it outdoors at least 6 metres (20 feet) away, with the exhaust facing away from windows and doors.
Can I plug my generator into a wall socket to power the house?
No. HSENI says don't connect a generator to your home's wiring, as it could cause a surge that may injure or kill. Running a house from a generator needs a changeover switch fitted by a qualified electrician, which cuts the house off from the grid first.
How much petrol can I store at home?
HSE says you can keep up to 30 litres at home without telling anyone, in suitable containers: plastic ones up to 10 litres each, metal ones up to 20 litres, or one demountable tank up to 30 litres. It must not be stored in your living accommodation. More than 30 litres means notifying your local Petroleum Enforcement Authority.
Do I need a carbon monoxide alarm if the generator is outside?
Yes. HSENI advises battery-powered carbon monoxide alarms inside the home when you use a generator. Fumes can drift in through doors, windows and vents.
Sources
We opened each page on the date shown. Official advice changes: if a source says something different now, follow the source.
- UK Chief Medical Officers (GOV.UK, published 16 December 2025): Keeping warm or cool in extreme weather, scripts for broadcast media (read 1 November 2026)
- HSENI (26 January 2025): Safety tips for using a portable generator in an emergency (read 1 November 2026)
- NHS: Carbon monoxide poisoning (reviewed 16 December 2025) (read 1 November 2026)
- HSE: If you store petrol at home, or at a club, association or similar premises (read 1 November 2026)
- ESB Networks (Ireland): Can I use my generator during an electricity network power outage? (read 1 November 2026)
- Ofgem: Join your supplier's Priority Services Register (read 1 November 2026)
- GOV.UK Be Ready: emergency kit (read 1 November 2026)
Related guides
- Carbon monoxide at home: signs, alarms and what to do
- Do you need a portable power station for power cuts?
- Power cut kit: what to keep in one box, and how long power cuts last
- Winter power cut checklist for UK homes
Free tools
We're an independent UK site, not the government. We check guides against official sources and link to them. In an emergency call 999.
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