PLT/General/TBT-PLT-022

Portable Generator Safety

Plant & Equipment › General › Portable Generator Safety

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Portable generators provide temporary electrical power for tools, lighting, and welfare on construction sites.
Carbon monoxide (CO) from generator exhaust is a colourless, odourless gas that kills in enclosed spaces.
Generators must never be operated inside buildings, containers, or partially enclosed areas.
Electrical output should be 110V via a centre-tapped earth transformer for construction site use.
Refuelling a hot or running generator creates a fire and explosion risk from fuel vapour ignition.
Generators vibrate and produce noise levels typically exceeding 85 dB, requiring hearing protection.
Trailing cables from generators must be protected from damage, water, and traffic on site.
Earth leakage protection (RCD) must be fitted to the generator output for user safety.
Fuel storage and handling must comply with the site COSHH assessment and fire prevention plan.
Pre-use checks should cover fuel level, oil, coolant, output voltage, and earth connections.

Carbon monoxide	CO poisoning from generators in enclosed spaces causes death within minutes — it cannot be detected without a monitor.
Electrical safety	Incorrectly connected or unprotected generator supplies create electric shock and fire hazards.
Fire risk	Refuelling a hot generator can ignite fuel vapour, causing burns and fire on site.

Don't

Position generators outdoors in well-ventilated areas away from building openings
Use 110V centre-tapped earth output for all construction site power tools
Fit RCD protection to the generator output to protect against earth faults
Allow the generator to cool before refuelling and mop up any fuel spills
Complete pre-use checks on fuel, oil, output voltage, and earth connections
Protect trailing output cables from damage by vehicles and pedestrian traffic
Wear hearing protection when working near the generator during operation
Store fuel in approved containers in a bunded area away from ignition sources
Switch off the generator and disconnect loads before carrying out any maintenance
Keep a fire extinguisher within reach of the generator at all times

DON'T operate a generator inside a building, container, or partially enclosed space
DON'T refuel the generator while it is running or still hot from operation
DON'T connect a generator to a building's mains supply without a transfer switch
DON'T use a 230V generator output for portable tools on construction sites
DON'T run output cables through standing water or across wet ground without protection
DON'T overload the generator beyond its rated output capacity
DON'T ignore CO poisoning symptoms — headache, dizziness, and nausea — leave the area
DON'T leave the generator running unattended overnight without security measures
DON'T store fuel cans next to the generator exhaust or engine
DON'T bypass the RCD to keep the generator running after a trip

See also: Carbon Monoxide Poisoning | RCD Protection and 110 Volt Use

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