Backup Generators · Service

Setting up a portable generator properly

Most of this you can do yourself, and we will say so. There is exactly one part worth paying an electrician for, and one part that kills people every single storm season — and they are not the same part.

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In short

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.

The job

How portable generator setup actually works

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 for: A 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.
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 for: A 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.
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 for: Daisy-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.
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 for: Anyone 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.
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 for: A 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.
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 for: Buying 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.

Money

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 →

Straight answer

When portable generator setup is the wrong call

Everyone else ranking for this is paid when you say yes. Here's when you shouldn't.

You will not be home to start it. A portable needs a person, in the weather, with a torch. If the property is unoccupied, or the outage matters immediately because of a sump pump, a well or medical equipment, this is the wrong product and a standby machine is the right one.
Your outages last days, not hours. Someone has to refuel it repeatedly, including overnight, and petrol is exactly what runs out locally in a regional event. Long outages are the case standby generators exist for.
You need central air conditioning, an electric range, a dryer or an electric water heater. These are generally out of reach of a portable, and a plan that depends on them will disappoint on the first hot night.
You have nowhere safe to run it. An apartment, a balcony, a townhouse with no yard, or a lot where the only sheltered spot is a carport or a porch. There is no safe compromise here — if the only place to put it is somewhere enclosed, do not buy it.
You cannot safely store fuel. No shed, no detached garage, or local rules limiting what you can keep. A dual-fuel machine on propane is worth considering instead, since propane stores indefinitely.
You want it to run the house through a wall outlet. That is not a cheaper version of a transfer switch, it is a backfeed, and it is covered in the danger note below. If the switching gear is not in the budget, use the machine on cords and keep it out of the house wiring entirely.

Straight answer

Can I do this myself?

Two things kill people with portable generators, and neither is the electricity you are thinking of. The first is carbon monoxide — running a generator in a garage, a carport, a porch, a basement or a shed, even with the door open, allows exhaust to accumulate and it is odourless and fast. Run it outdoors, well away from doors, windows and vents, and have working CO alarms inside. The second is backfeeding — connecting the generator to a wall outlet with a double-ended cord to power the house. It sends current back onto the utility network where it can kill the crews restoring your power, and it bypasses your panel's overcurrent protection. Neither of these is a risk you manage carefully. They are things you do not do.

Reasonable to DIY

Choosing, buying, positioning and starting the machine, and keeping it serviced
Running appliances directly from it on correctly rated outdoor extension cords
Storing and rotating fuel in approved containers, away from the house and ignition sources
Testing your carbon monoxide alarms and replacing their batteries
Changing the oil and the air filter, and running it periodically so it starts when you need it

Call a licensed pro

Fitting the power inlet box and the transfer switch or listed interlock. This is panel work, it is permitted and inspected, and it is the only way to reach hard-wired circuits safely.
Any question about whether your panel has room, or whether your jurisdiction accepts an interlock kit for your specific panel.
Diagnosing a machine that starts and then drops the load, which is usually an alternator or regulator fault rather than an engine problem.

Before you sign

What to check when hiring for portable generator setup

Can you fit a power inlet and switching gear so this runs my furnace and well pump?

The actual job you are hiring for. Be specific about the hard-wired loads you want reached — that determines the arrangement.
Will an interlock kit work on my panel here, and is it accepted locally?

Where it is, it costs far less than a transfer switch and reaches every circuit. It must be listed for your specific panel, and acceptance varies.
Where do you recommend the inlet, given where the generator has to stand?

The inlet position dictates the generator position. Get it fitted so the safe spot for the machine is also the convenient one.
What cord rating do I need between the machine and the inlet?

A specific rating for a specific inlet and current — not the cord that came in the box. Get the specification rather than guessing at the store.
Is a permit and inspection included?

Permitted in most places, and unpermitted electrical work is a problem at sale and after any fire claim.
Will you show me the whole sequence at handover?

Start, connect, throw the switch — in that order, with you doing it. In the dark and the rain, muscle memory beats an instruction sheet in a drawer.

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FAQ

Portable Generator Setup — questions people ask

Still have a question? Talk to our team →

Can I run a portable generator in my garage with the door open?

No. This is the single most common fatal mistake with portable generators, and an open door does not make it safe — exhaust accumulates in the enclosed volume and drifts into the house, and carbon monoxide gives you no warning because it has no smell and no colour. The same applies to carports, covered porches, basement stairwells and sheds. Run it outdoors, well clear of doors, windows and vents, with the exhaust pointed away, and have working CO alarms inside.

Can I plug a portable generator into a wall outlet to power my house?

No, and it is worth being blunt about why. That arrangement pushes generator power back through your panel and out onto the utility network, where it can electrocute line workers who have every reason to believe those conductors are dead. It also bypasses the overcurrent protection in your panel and leaves the cord pins live and exposed. The correct route to your house wiring is a transfer switch or a listed panel interlock, fitted by an electrician.

What size portable generator do I need?

Build a list of what you want running at the same time, then look up the starting surge of everything with a motor in it — a refrigerator compressor, a freezer, a sump pump, a well pump each draw several times their running wattage for a moment. The machine is chosen from the surge total. Be realistic about what is excluded: central air conditioning, electric ranges, dryers and electric water heaters are generally outside portable territory.

Is a portable generator worth it compared with a standby?

It depends entirely on your outage pattern and whether someone is home. For occasional outages of a few hours in a household that is present, a portable plus an inlet and switching gear covers the important things at a fraction of the cost. For multi-day outages, unoccupied properties, sump pumps, wells or medical equipment, the fact that a portable needs a person to start and refuel it is a decisive limitation rather than an inconvenience.

Why will my generator not start when I need it?

Almost always fuel or neglect rather than a fault. Petrol degrades over months and stale fuel is the leading cause of a no-start, followed by a carburettor gummed up from being stored with fuel in it, an empty or old battery on electric-start models, and oil that is low enough to trigger the low-oil shutdown. All of it is prevented by starting the machine every few months under some load, which takes ten minutes and is the highest-value maintenance you can do.