Why You Should Never Plug a Generator Straight Into an Outlet
Running a cord from the generator into a wall outlet in the house (sometimes called 'backfeeding') does power the appliances inside, but in the same movement it also energises the outdoor utility line the house is still connected to. Current produced by the generator then travels back along the grid, at a voltage that can be lethal to a utility worker repairing a line they believe has been switched off, sometimes hundreds of metres away.
How to Connect a Generator to a House, the Safe Way
The only safe way to wire a generator into a house's electrical circuit is through a transfer switch (manual or automatic), a device that physically isolates the generator's circuit from the utility grid: current simply cannot travel back outward.
- 1. Have a transfer switch installed by a qualified electrician. This step is not optional, it is what makes everything else safe, and it must be done before the first outage, not during one.
- 2. Place the generator outdoors. At least 6 m from any window, door or air intake, never in a garage even with the door open, to prevent any build-up of carbon monoxide.
- 3. Start the generator and let it stabilise. Wait a few minutes of steady running before flipping the transfer switch, so the engine reaches operating temperature.
- 4. Flip the transfer switch to the generator position. This action physically disconnects the house circuit from the utility grid at the exact moment it connects it to the generator.
- 5. Reconnect circuits gradually. Avoid starting every appliance at once: prioritise the fridge, essential lighting and heating over secondary appliances, to stay within the generator's available output.
- 6. When utility power returns, flip the transfer switch back. Switch back to the grid before shutting the generator down.
What Size Generator Does a House Need?
A home backup generator does not need to power the entire house at once: the goal is to cover the essential circuits. Budget around 3000 to 3500 W for the fridge, lighting and a few common outlets, and 5000 to 7000 W if heating or a well pump also need to be covered. Appliances with a heavy starting draw (pumps, fridge compressors, some power tools) demand a peak output well above their normal running wattage, worth checking before settling on a model.
The Mistakes That Make a Generator Dangerous
Other common mistakes: plugging directly into a wall outlet without a transfer switch (see above); refuelling with the engine hot or running, a real fire risk; overloading the generator beyond its rated output, which can damage it and the appliances connected to it; and leaving it out in the rain without a suitable ventilated shelter.
