Home Generator Safety: How to Use One Without Carbon Monoxide Risk

Why a generator can kill

Engines that burn fuel give off carbon monoxide, a gas you can’t see or smell. According to the U.S. Consumer Product Safety Commission (CPSC), one portable generator produces as much CO as hundreds of cars, and poisoning can happen so fast that people pass out before they realise they feel unwell.

It isn’t a rare risk. The CPSC estimates that about 85 people die each year in the United States from CO from gasoline generators (average for 2017 to 2019), and that 81% of those deaths happen at home. The most common reason those people were using a generator was a weather-related power outage.

Where to put the generator

• Never indoors: not in the house, garage, basement, crawlspace, shed or porch. The CPSC warns that opening doors and windows isn’t enough to stop CO building up.
• Outside and far away: the CPSC and the U.S. Centers for Disease Control and Prevention (CDC) say more than 20 feet (about 6 metres) from the house and from any door, window or vent.
• Exhaust pointing away: the fumes should blow away from the house and any building someone could enter, with the windows on that side closed.
• With space around it: the U.S. workplace safety agency (OSHA) asks for 3 to 4 feet (about 1 metre) of clear space on all sides and above.
• Dry: OSHA says not to use it in the rain or wet conditions. If needed, protect it with a canopy, without enclosing it. Never handle it with wet hands or while standing in water.

The carbon monoxide alarm

Because the gas can’t be seen or smelled, the only way to find out in time is an alarm. What the CPSC and CDC recommend:

• An alarm that runs on batteries or has battery backup (in an outage, a plug-in-only alarm won’t work), on every level of the home and near sleeping areas.
• Test it once a month with its button, like in the photo above.
• Replace it when the manufacturer says, or every 5 years.
• If it sounds, never ignore it: get outside straight away and call emergency services.

The CPSC also advises that, when buying a generator, you look for one that shuts off automatically when CO levels are high.

Symptoms of poisoning and what to do

According to the CDC and the UK’s NHS, the most common symptoms are headache, dizziness, weakness, nausea or vomiting, chest pain and confusion. They’re often mistaken for flu. The NHS adds a clue: they get better when you leave the building and worse when you go back in.

The CDC warns that people who are asleep or have been drinking can die without ever noticing anything. Babies, older people and those with heart disease, anaemia or breathing problems are more affected.

If you suspect poisoning:

1. Switch off the generator if you can do so safely, and get outside into fresh air with everyone in the home.
2. Call emergency services or get medical help straight away. If someone is confused, struggling to breathe or has passed out, call an ambulance: the NHS says not to drive yourself.
3. Don’t go back inside until you’re told it’s safe.

Never connect the generator to your home’s wiring

OSHA is clear: a generator must not be connected to a building’s electrical system unless a qualified electrician has installed it with a transfer switch, the device that separates the house from the grid. Without one, power from the generator can travel out of your home into the lines outside and electrocute the workers repairing the fault, or anyone nearby.

The safe way is what OSHA says: plug appliances straight into the generator, using the cords it came with or grounded (three-prong) extension cords that are intact, undamaged and rated for the watts or amps you’ll connect.

Fuel and fire risk

According to OSHA, a generator gets very hot and stays hot for a long time after it’s switched off, and fuel spilled on a hot engine can catch fire. So:

• Switch it off and let it cool before refuelling.
• Store gasoline in approved containers made for it, outside the home and away from any flame or heat source, including the generator itself.
• Don’t smoke nearby: fuel vapours can travel a long way.
• Don’t overload it: that makes it overheat and can start a fire.

What size, and what’s the alternative

You choose a generator the same way as an inverter, using the method of the U.S. public utility EWEB: it has to supply everything you’ll run at the same time and handle the start-up of the most demanding motor. A fridge, 4 LED bulbs, a fan, 2 chargers and the TV come to 426 W running and 1,026 W at start-up. We explain it step by step in our inverter article.

If you only need to keep the fridge, lights and chargers going, also consider a battery or portable power station: it doesn’t burn fuel, so it gives off no CO and can be used indoors. Work out which one you need with our power outage battery calculator, and for fridge food see how long it lasts without power.