Setting up a portable generator properly

What is portable generator setup?

A portable generator is a petrol or dual-fuel engine on a frame that you roll out, start by hand and run appliances from. Setting one up properly means three things: putting it somewhere its exhaust cannot reach the house, using cords heavy enough for the load and the distance, and - if you want it to run anything that is hard-wired, like a furnace or a well pump - having an electrician fit a power inlet and switching gear. That last part is the only piece that genuinely needs a professional.

How portable generator setup actually works

1. 1

   Work out what you actually need to run, honestly

   Write the list: refrigerator, freezer, furnace controls and blower, a few lights, the router, phone chargers, maybe a well pump. Then look at the starting surge of the motor loads - refrigeration compressors and pumps draw far more for a moment than they do running. A portable is chosen from the surge numbers, not the running numbers.

   Watch forA list that quietly includes central air conditioning, an electric range, an electric water heater or a dryer. Those are generally beyond a portable, and building a plan around them is how people conclude their new generator is faulty.

2. 2

   Decide where it runs, before you buy it

   The machine runs outdoors, on a hard level surface, well away from doors, windows, vents and anything partly enclosed, with the exhaust directed away from the house. Manufacturers state a minimum distance and the honest advice is to exceed it. This is also where you find out whether you have anywhere suitable at all.

   Watch forA plan that involves the garage with the door open, a carport, a covered porch, a basement stairwell, or a shed. All of these are enclosed enough to accumulate exhaust and all of them appear in fatality reports every storm season.

3. 3

   Size the cords for the load and the distance

   Extension cords have to be rated for outdoor use, undamaged, and heavy enough for both the current and the run length - voltage drop over a long thin cord makes motors run hot and appliances misbehave. Cords are uncoiled fully rather than run from a reel, and routed where nobody trips and no door closes on them.

   Watch forDaisy-chained indoor cords, or a cord run under a rug or through a doorway. Cord problems cause fires, and a door closed on a cord is both a damaged cord and an open path for exhaust.

4. 4

   Have an inlet and switching gear fitted - the part to hire out

   This is where a professional earns their money. An electrician fits an exterior power inlet box and either a transfer switch or, where permitted, a listed panel interlock, so the generator can feed hard-wired circuits - furnace, well pump, sump pump - through your own wiring. It is permitted, inspected work and it is what makes a portable genuinely useful.

   Watch forAnyone offering to "just wire in a plug". If the arrangement does not include a listed switch or interlock, it is a backfeed, and the danger block below explains why that is not a corner to cut.

5. 5

   Sort out fuel storage and keep it fresh

   Petrol degrades in storage and stale fuel is the commonest reason a portable will not start when you need it. Store it in approved containers, away from the house and any ignition source, in the quantity your local rules allow, and rotate it through the car so it never gets old. Dual-fuel machines running on propane sidestep this entirely, because propane does not degrade.

   Watch forA can of petrol that has been in the shed since the last storm. Also: refuelling a hot engine. Let it cool - petrol on a hot exhaust is exactly as bad as it sounds.

6. 6

   Run it before you need it

   Start the machine every few months, let it run under some load, and check the oil. A generator that has sat untouched for two years is a generator that will not start on the night, and you will be discovering that by torchlight in the rain.

   Watch forBuying the machine, putting it in the garage and never starting it. It is the single most common reason a portable fails its owner, and it is entirely free to prevent.

What does portable generator setup cost?

The machine itself is a retail purchase across a wide range depending on output and features. The part that involves a contractor - an exterior inlet box plus a transfer switch or listed interlock - is typically a half-day of electrical work plus parts and the permit. See the generator cost guide for ranges.

See the full portable generator setup cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →