What Should You Not Plug Into an Inverter Generator?
Don't plug anything into an inverter generator that needs more than its running rating, or more than its starting rating when a motor kicks in. Power quality is rarely the problem. Overloading is, plus one safety-switch catch.
Loads That Overload an Inverter Generator
An inverter generator has two numbers on the spec sheet. The running (continuous) rating is what it holds all day, and the starting rating is a short burst for motors. Plan against the running figure.
| Appliance | What to check | Verdict |
|---|---|---|
| Phone and laptop chargers, LED lights, TV | Running watts | Fine within the rating on a pure sine wave inverter generator |
| Fridge or freezer | Motor starting surge | Fine if the starting rating covers it |
| Caravan or house aircon | Compressor starting surge | Only on a generator sized for the start |
| Kettle, heater, hair dryer | Rating plate against 80% of the running rating | Leave it off if it's over |
| Power board of earthed appliances | Floating output, RCD won't trip | Leave it off, one appliance per lead |
| EV charger with a mains plug | Earth detection | May not work on an inverter at all |
Heaters, Kettles and Hair Dryers
Anything that makes heat draws its full rating the whole time it's on. Read the rating plate and compare it with the generator's running rating, not the starting rating.
The Electrical Safety Office says your generator should not run continuously at more than 80 per cent of its rated capacity. On the Westinghouse iGen2250, with 1,800W continuous, that's 1,440W. If your kettle's plate says 2,200W, it's not going on that generator, and the listing itself says the iGen2250 is the wrong pick if you want headroom for a kettle plus other gear.
Fridges, Freezers and Aircon Compressors
Motors are the sneaky ones. The Electrical Safety Office says fridges and freezers can use up to ten times their listed wattage when starting, and its portable generator guidance puts aircons, fridges and freezers at two to 10 times their rated load at start-up.
That's how a generator can run a caravan fridge all afternoon and then trip when the aircon compressor cuts in on top of it. Size for the biggest start, and read plugging a caravan into a generator if the van's involved.
Everything at Once
Energex's advice is to turn appliances on one by one, rotate the use of larger items, and not try to connect many appliances at the same time. Stagger the big loads and let each one settle.
Our generator size guide does the adding up for you.
Power Boards, RCDs and Earthed Appliances
Why an RCD Won't Trip on a Floating Output
Small inverters and many small generators have a floating output, with no connection between the output and earth. Jaycar's help centre says that with a floating output, the dangerous condition an RCD is designed to prevent can't occur, and that pressing the test button on a fitted RCD won't trigger it.
The flip side is that a plug-in RCD gives you nothing on that supply. Ampfibian's FAQ says RCDs do not offer protection when used with isolated supplies like small generators or inverters.
Power Boards Full of Earthed Gear
A Grey Nomads forum member warned that plugging a power board into an inverter carries serious safety risks with anything other than double-insulated appliances. In the unlikely event of faults, they said, you could be electrocuted by touching two appliances at the same time.
A licensed electrician in the same thread added that an RCD won't trip on an isolated supply, and pointed to residual voltage devices built for them. The simple fix is the Electrical Safety Office's: use a good quality extension lead from the generator directly to the appliance. One appliance, one lead.
EV Chargers and Earth-Sensing Equipment
Portable EV chargers with a mains plug can refuse to work. Jaycar says this kind of equipment often needs the same earth detection as an RCD before it'll start charging, so it may not work on any inverter, including the inverter in a portable power station.
Inverter Generators vs 12V Power Inverters
Search this question and most results are about 12V power inverters, the kind wired to a battery in a ute or van. The answer overlaps, but it isn't the same.
Sensitive Electronics on an Inverter Generator
A decent inverter generator makes pure sine wave power with low harmonic distortion. The iGen2250 is listed at under 2.5% THD, and the Champion 2.5kVA at under 3%, with 1,900 running and 2,500 starting watts. Laptops, TVs and phone chargers are fine within the rating.
If you're worried about a particular device, will generators damage electronics and how voltage regulation works in generators go deeper.
What Not to Plug Into a Modified Sine Wave Inverter
Cheaper 12V inverters often put out a modified sine wave, and that's where the list gets longer. US inverter retailer DonRowe.com publishes appliance cautions for modified sine wave inverters. Don't directly recharge small appliances that plug straight into the socket, don't plug in cordless tool chargers that warn of dangerous voltages at the battery terminals, and check with the maker before running medical equipment like oxygen concentrators.
Watch the 12V side too. As one Grey Nomads member pointed out, drawing 300W from an inverter pulls about 30A from the 12V system, well over the typical 10A of a cigarette lighter socket.
The short list for an inverter generator: nothing over 80% of the running rating for long, no stacked motor starts, no power boards of earthed gear, and don't count on an EV charger. And never plug the generator itself into a house power point, which is backfeeding.
Not sure which size covers your gear? Try the generator finder, compare the quiet options in our best inverter generator guide, or call us on 03 7056 6732, or SMS 0476 330 590.
