Generator Safety: Carbon Monoxide, Earthing and Fire Risk

A generator gives a household power when the grid fails, but it also brings three hazards into the home that the grid never does: a fuel-burning engine that exhausts carbon monoxide, flammable fuel stored on the premises, and a supply of electricity that must be safely connected and earthed. The numbers behind these risks are real. Every year about 30 people in the UK die from carbon monoxide poisoning caused by gas systems which have not been properly installed or maintained¹, and the Health and Safety Executive reports that around 7 people die from gas-related carbon monoxide poisoning every year². A government consultation puts the England and Wales figure for carbon monoxide poisoning overall at approximately 40 deaths reported each year³. Half of accidental domestic fires in the UK are caused by electricity⁴.

None of these risks mean a generator has no place in a resilient home. They mean the safety rules have to be taken as seriously as the power output. This page sets out what the official guidance and the wiring regulations actually require, where the deaths and fires come from, and what remains dependent on outside help even when the generator is running.

Why the numbers make generator safety non-negotiable

The case for treating a generator as a serious piece of equipment rests on the casualty and fire figures. Official guidance states that every year about 30 people in the UK die from carbon monoxide poisoning caused by gas systems which have not been properly installed or maintained¹. The Health and Safety Executive gives a narrower count, around 7 deaths a year from gas-related carbon monoxide poisoning², and a government consultation on the UK's product safety framework reports that in England and Wales approximately 40 deaths are reported each year due to carbon monoxide poisoning³. These figures differ because they count different things: gas systems only, gas-related causes only, and all reported carbon monoxide poisoning. What they agree on is that the hazard kills people in ordinary homes every year.

The fire statistics point the same way. Electrical Safety First reports that every year, half of accidental domestic fires in the UK are caused by electricity, and that this figure is not changing⁴. Building regulations for electrical work exist, in the official wording, because "these rules have been introduced to help reduce the number of deaths, injuries and fires caused by faulty installations"⁶. A generator adds a new electrical installation to a home, plus an engine and fuel, so it sits at the junction of both sets of statistics.

For a household pursuing energy independence, this is the honest accounting. A generator reduces dependence on the grid for supply, but it increases dependence on doing things correctly: siting, earthing, fuel storage and alarm coverage all have to be right, every time it runs.

The unseen danger of carbon monoxide from fuel-burning appliances

Carbon monoxide is the hazard that makes fuel-burning generators different from every other piece of backup equipment. Official guidance is blunt about it: "Carbon monoxide is a highly poisonous gas which you can't see, taste or smell, but it can kill quickly without warning."⁷ Independent guidance from OFTEC calls it the "silent killer" for the same reasons: it is colourless, odourless and tasteless⁸. nidirect adds simply that carbon monoxide is a poisonous gas that has no smell or taste⁹.

The connection to generators is explicit in the official record. nidirect notes that "incidents and fatalities because of CO can also occur in holiday homes, caravans and on board boats where faulty gas cookers, appliances or petrol-powered generators have led to carbon monoxide poisoning"¹⁰. Petrol-powered generators are named as a direct cause of deaths, and the settings listed, caravans, holiday homes and boats, are exactly the confined or semi-confined spaces where people are tempted to run a small engine under cover.

The mechanism is simple. An engine burning petrol, diesel or LPG exhausts carbon monoxide along with the other combustion products. Outdoors, the gas disperses. Indoors, or in a garage, doorway or lean-to, it accumulates, and because it has no smell, the people breathing it get no warning. The first symptoms are easily mistaken for something else, and official guidance is clear about the response: "Go immediately to your local emergency department if you think you or someone with you has been exposed to carbon monoxide."⁹

For a household, the independence lesson is that a fuel generator's exhaust is a hard limit on where it can be used. No amount of ventilation through a propped door makes an enclosed space safe, and the alarm inside the home is the last line of defence, not the first.

Siting a generator outdoors: the only safe arrangement

The rule that follows from the carbon monoxide hazard is that a fuel-burning generator runs outdoors, away from the building. The official record of deaths from petrol-powered generators in caravans and boats¹⁰ is the clearest statement of what happens when that rule is broken, and it applies with equal force to a garage with the door open: an open door is not ventilation, it is a slower route to the same concentration.

What the official guidance adds is the framework around the installation itself. Building regulations for electrics apply to electrical installation work in the home or garden in England and Wales⁶, and the purpose of those rules, in the official wording, is to reduce deaths, injuries and fires caused by faulty installations⁶. A generator that supplies the house, even through a transfer switch, is electrical installation work, and in Wales the requirement is that an electrician registered by an organisation authorised by the Secretary of State can certify the work as safe without notifying Building Control¹¹.

The practical arrangement that follows from the guidance is:

• The generator sits outdoors, in the open air, with the exhaust directed away from the building.
• Doors, windows and vents that could carry exhaust indoors are kept clear of the exhaust path.
• The electrical connection into the home is made through proper transfer switches and wiring, not through a wall socket.
• A carbon monoxide alarm inside the home provides warning if exhaust finds its way in despite the siting.

The dependence that remains is worth naming: a fuel generator sited safely outdoors is exposed to the weather, and its safe operation depends on the household following the siting rule every single time it is used. For more on the equipment itself, see portable generators for home backup and standby generators for homes.

CO alarms: the standard to look for and where to fit them

A carbon monoxide alarm is the device that turns an invisible hazard into an audible warning. The Health and Safety Executive's advice to householders is specific about what to buy: "Before purchasing a CO alarm, always ensure it complies with British Standard EN 50291 and carries a British or European approval mark, such as a Kitemark"². OFTEC's independent guidance states the same requirement, describing a carbon monoxide detector as one "performing to British standard BS EN 50291"¹².

Where alarms are required gives a sense of where they belong. In rented properties in the UK and Jersey, CO detectors must be fitted in any room used as living accommodation containing an appliance⁸. A household running a generator does not fall under that landlord duty, but the logic transfers directly: fit alarms in the rooms where people are, and especially where they sleep, and in any room where a fuel-burning appliance sits.

The response to an alarm matters as much as the alarm. Official guidance says to seek medical help from a qualified healthcare professional if poisoning is suspected⁹, and to go immediately to the local emergency department if exposure is suspected⁹. The HSE's own carbon monoxide page advises that anyone experiencing symptoms and believing they may have been exposed "should seek urgent medical advice from either your GP or an A&E department"¹³. OFTEC gives the same route: contact your GP or go to your local accident and emergency department¹².

For a household with a generator, the alarm is not optional equipment. It is the only device in the home that can detect the specific hazard the generator creates, and it costs a fraction of the generator itself.

Wiring regulations and earthing: meeting BS 7671 requirements

The electrical side of generator safety is governed by BS 7671, the IET Wiring Regulations. The current edition is BS 7671:2018+A4:2026, published on 15 April 2026, which supersedes BS 7671:2018+A2:2022+A3:2024⁵. The standard is described as the UK's national standard for the design, erection and verification of electrical installations⁵, and it is the most widely accepted way to demonstrate compliance with UK electrical safety legislation, namely the Electricity at Work Regulations 1989⁵.

Government guidance states the requirement plainly: "All electrical work should follow the safety standards in BS 7671 (the 'wiring regulations')"⁶, and the standards that should be met for electrical safety are set out in British Standard 7671¹⁴. In Northern Ireland, the electrical safety standards are defined in legislation as the standards for electrical installations in the eighteenth edition of the Wiring Regulations, published by the Institution of Engineering and Technology and the British Standards Institution as BS 7671: 2018¹⁵.

What this means for a generator installation is that the connection into the house is not a DIY job. Planning Portal guidance for England and Wales states that even non-notifiable work "should be designed and installed, and inspected, tested and certificated in accordance with BS 7671"¹⁶. In Wales, an electrician registered by an organisation authorised by the Secretary of State can certify work as safe without notifying Building Control¹¹. A generator supply that is not correctly earthed and not correctly separated from the grid supply creates a shock hazard in the home and a live hazard for network engineers, which is why the connection and transfer switch rules exist and why the work belongs to a registered electrician.

The dependence here is on competence. A household can own the generator, but the safe interface between it and the house wiring depends on a qualified person and a published standard that is updated, as the 2026 amendment shows, to reflect modern installations including renewable energy systems.

Fuel storage, LPG and the fire regulations

The fuel a generator burns is itself a regulated hazard. Building regulations Approved Document J, which covers heat-producing appliances, sets out Requirement J6 for fuel storage: "Liquid fuel storage systems and the pipes connecting them to combustion appliances shall be so constructed and separated from buildings and the boundary of the premises as to reduce to a reasonable level the risk of the fuel igniting in the event of fire in adjacent buildings or premises."¹⁷ That requirement applies to fixed oil storage tanks with capacities greater than 90 litres and fixed LPG storage installations with capacities greater than 150 litres located outside the building¹⁷.

The principle behind Requirement J6 applies to smaller quantities too: fuel stored for a generator should be separated from the building and the boundary so that a fire elsewhere does not ignite it, and so that a fuel fire does not spread into the home. For householders storing petrol, diesel or LPG for a generator, the detailed rules are covered on storing fuel at home.

Refuelling is the moment of highest risk. Pouring petrol or diesel into a hot or running engine, or changing an LPG cylinder next to a lit appliance, puts flammable liquid or gas in contact with an ignition source. The safe sequence is always the same: shut the generator down, let it cool, then refuel away from the building. On the gas side, the legal framework is strict about who may work on gas: "You must be on the Gas Safe Register to carry out gas work legally."¹⁸ A householder changing an LPG cylinder connected to a generator is handling regulated fuel equipment, and permanent gas connections belong to a registered engineer.

The independence trade-off is plain: a fuel generator stores independence in a can, but that can is a fire load on the property, and its safe storage is a continuing obligation, not a one-off purchase.

What the figures reveal about household fires

The fire statistics give the electrical side of generator safety its context. Electrical Safety First reports that "Every year, half of accidental domestic fires in the UK are caused by electricity, and this figure isn't changing."⁴ The organisation attributes these fires to misuse of appliances, poor regulation of electrical safety checks, particularly in the private rented sector, and faulty appliances⁴, and it is campaigning for mandatory five-yearly electrical checks in rented homes⁴.

The white goods figure shows how ordinary the risk is: over five fires a day in England are caused by white goods such as tumble dryers, washing machines and dishwashers⁴. A generator, its fuel and its connection into the household circuits add to the electrical fire load of the home, and the same causes, faulty equipment and misuse, apply. A generator left running unattended, overloaded, or connected through improvised wiring is exactly the kind of installation the fire statistics are made of.

There is also a forward-looking risk worth noting. The Climate Change Committee reports that hotter heatwaves could see 92% of existing homes overheat, creating dangerous conditions for vulnerable people¹⁹. Fuel storage and hot, enclosed spaces are a poor combination, and a household planning long-term resilience should think about where fuel and equipment sit as summers warm.

The practical response is the same as for any electrical fire risk: sound installation to BS 7671, no improvised connections, alarms fitted and tested, and fuel stored away from the building. See also backup power safety, wiring regulations and standards for the wider framework.

Recalled products: why you must stop using them

Generators, chargers and battery products are recalled, and a recalled item in a home is a known hazard sitting on the shelf. Electrical Safety First's guidance on recalled products is unambiguous: it "strongly recommends that anyone who discovers they have an electrical item that has been recalled" stops using it until it has been checked by the manufacturer²⁰. Its product-specific advice is firmer still: "If you believe you have an affected product stop using it immediately and contact the retailer for further advice."²⁰

Recalls are not rare events. Electrical Safety First's recall listings include items such as the Cambridge Audio Yoyo (M) Portable Bluetooth Speaker, recalled in August 2026²¹, the SavePower Universal Standby Saver, recalled after reports of units catching fire during use²², and a USB charger recalled as a listed product safety notice²³. The pattern is consistent: electrical products sold into UK homes develop faults, and the recall system is the mechanism for catching them before they cause fires.

For a household with backup power equipment, the habit that follows is simple: check the recall listings when buying second-hand equipment, and check again if an item behaves oddly. Battery products carry their own recall history, covered in detail on lithium battery safety and recalls and power bank recalls. The UK's product safety framework is itself under review, with a government consultation on a new product safety framework reporting that approximately 40 deaths a year in England and Wales are due to carbon monoxide poisoning³, a reminder that product safety and poisoning statistics are part of the same system.

Fuel generators versus solar generators: two different safety profiles

A solar generator, meaning a portable power station charged from panels, removes the two hazards that define fuel generator safety: it has no exhaust and it stores no flammable liquid. There is no carbon monoxide, because nothing is burned, and no fuel can to store away from the building. That is why the question of running equipment indoors has a different answer for each type: a fuel generator belongs outdoors, while a power station is designed for indoor use, as covered on are portable power stations safe to use indoors?.

The regulatory position around plug-in solar is worth knowing. A government consultation states that "At present, solar plug-in microgenerators cannot be legally sold, supplied, or used in the UK due to constraints arising from existing product safety legislation"²⁴, and that "plug-in solar products will be covered by the General Product Safety Regulations (GPSR) 2005 in Great Britain"²⁴. So while a solar generator removes the combustion hazards, the products around it are still inside the product safety system, and the recall rules in the previous section apply to them as much as to any charger.

The comparison is not one-way in favour of either type. A fuel generator carries the carbon monoxide, fuel and fire risks this page has set out, but it can run indefinitely with fuel. A solar generator carries none of the combustion hazards but depends on daylight and on the battery's own safety record, and its capacity is finite. The full comparison, including cost and runtime, is on solar generator vs fuel generator and portable power station vs generator.

For energy independence, the safety profile is part of the choice: a household that cannot guarantee outdoor siting and disciplined fuel handling is safer with equipment that never burns anything, while a household that can site and maintain a fuel generator properly gains a supply that weather and daylight do not limit. Either way, the alarms, the earthing and the recall checks remain the household's own responsibility.