The Ontario Electrical Safety Code specifies that ‘under no circumstances shall a generator be connected to any portion of a wiring system except where it is connected through a transfer device that makes it impossible for the generator to feed back into the normal power supply.’ A transfer device is required between the utility system and the generator for safety, to prevent:
- Power from feeding back into the power supply line and endangering the lives of hydroelectric workers trying to restore power, and
- Accidental re-energizing of the farm, commercial or home service system and consequent burnout of the generator when regular service is restored; our generator guarantees are voided if a transfer switch is not used.
The transfer device should be sized according to the current rating of each service connected to it. It must be sized for 100% of the largest service, and 75% of the balance of services. Only a qualified electrical contractor following local electrical codes should install the transfer device.
The simplest and cheapest method is to use an extension cord, running only those few items you want to back up.
A Generator Transfer Panel is an simple method of hooking up a generator to your location. The generator panel receives power from your normal distribution panel while Hydro is doing their job. When grid power fails; you start your generator, plug it into a special plug and switch the generator panel to receive power from the generator. The generator panel powers only those circuits you have chosen to back up. This means you won’t need to go around turning things off etc. The panel shown at right is a combination panel, which in some cases will be more practical than using a separate generator panel because space is frequently limited.
The diagram at left shows a simple double throw switch and a small sub distribution or generator panel.