Using generators safely

During a power cut, or when we have to turn the power off to work on the power lines, generators can be used to run lights and appliances. Generally they are very safe, but you should follow a few rules when you use a generator.

Portable generators

Portable generators can be easily moved from site-to-site and are not intended to be connected directly to your home mains electrical system.  You should only use them to supply appliances through flexible cords.

You must never:

  • attempt to connect your generator to your mains switchboard, a wall outlet or by altering your house wiring. This could feed electricity back into our network and risk the lives of line workers
  • connect loads that exceed the generator's maximum output rating. Most generators have a maximum rating in watts, for example 2000 watts (two kilowatts)
  • use a generator indoors. You risk carbon monoxide poisoning from the fumes and also risk causing a fire
  • add fuel to the generator while it is running
  • use damaged leads or appliances. You should also use a safety switch designed especially for generators
  • connect all appliances at the same time; start with the largest and progressively add successive ones up to the generator's maximum output
  • 'piggy back' cords - always use a multiple-outlet box with built in load limiters.

Click to view: Portable Generator Safety - Virtual Demonstration.

Stand-by generators

Standby generators are designed to provide large amounts of power and are typically used in a business or commercial operation. Stand-by generators are connected directly to the businesses electrical system.


  • a licensed electrician must install the generator and alter the wiring as necessary
  • installations have either an automatic or manual changeover switch that disconnects the incoming mains and couples the generator to the installation wiring. This changeover must occur to stop electricity feeding back into our lines and putting the lives of line workers at risk
  • connected loads must not exceed the maximum rating of the generator. To limit the load to the maximum load rating of the generator, the installation wiring is split into essential and non-essential sections so that only the essential loads are supplied by the generator
  • to make sure that you are not billed for using the generator, the connection must be on the installation side of the energy meter
  • generators designed to start automatically in the event of a power cut should be test-run on load at periodic intervals. The best way to ensure that a generator will start and changeover if the mains fails is to turn off the building main switch

Please Note: all generators should be regularly serviced by a specialist company