How to Run Your House on a Generator

The three legitimate connections, cheapest first

Cords to plug-in appliances

No electrician, no permit, nothing permanent. Run a heavy-duty cord from the generator to a refrigerator, a plug-in space heater, a lamp, a sump pump that plugs into a receptacle in the pit.

The limitation is absolute and it is the reason the other two options exist: you cannot reach anything hard-wired. No furnace, no well pump, no hard-wired sump pump, no 240 V anything. For a lot of households that leaves out exactly the loads they wanted most.

An interlock kit

A steel plate on your existing panel cover that makes it mechanically impossible for the main breaker and a new generator breaker to be on simultaneously. Cheapest proper connection, and it gives you access to every circuit in the panel rather than a pre-chosen six or ten.

Two requirements. The plate must match your panel brand, amperage and breaker spacing exactly — see panel compatibility. And the install (the generator breaker, the inlet box, the feeder) is licensed electrical work, permitted and inspected in most jurisdictions.

A transfer switch

A sub-panel with a fixed set of circuits, each switchable between utility and generator and never both. More expensive, but it manages the load for you: the circuits were chosen at installation to total less than the generator can carry, so overloading is much harder.

Six or ten circuits is the usual choice. Six covers fridge, furnace, well pump, sump and two lighting circuits with nothing spare; ten adds kitchen outlets, a bathroom and room for later. Full comparison: interlock kit vs transfer switch.

The short answer

Connection hardware

#	Product	Best for	Score	Price
1	Reliance Controls 310CRK 10-Circuit 30A Kit The standard answer for connecting a portable generator properly: ten circuits, 30 A, from the brand electricians recognize.	The ten-circuit default	8.6/10★★★★★	$474.76
2	SPZOCE Interlock Kit — Square D QO/Homeline 150/200A The cheapest correct way to connect a generator to the whole panel, provided your panel is a Square D QO or Homeline with the exact spacing stated — measure first.	Square D QO and Homeline, 150-200A	8.5/10★★★★★	$26.99
3	Connecticut Electric EmerGen EGS1012KG2 50A 10-Circuit The simplest way to do a 50 A installation correctly: everything matched in one box, including the cord people most often get wrong.	50A kit with inlet and cord	9.0/10★★★★★	$379.99
4	Generac HomeLink 6852 30A Manual Choose this if a standby generator is a genuine plan for later; otherwise the Reliance kits do the same job for less.	A path to automatic later	8.0/10★★★★★	$368.87

#ad Prices as of October 5, 2026; they may have changed since. Scores are our editorial judgment from published specifications, not test results — how we pick. How we are funded.

The start-up sequence, which genuinely matters

1. 1Site and start the generator outdoors — 20 feet minimum, exhaust away from the house. Let it run for a minute to stabilize before you load it.
2. 2Turn off the main breaker (interlock) or set the transfer switch to generator. On an interlock this order is not optional: main off first, always.
3. 3Slide the interlock and switch on the generator breaker, or move the transfer switch circuits across.
4. 4Add the biggest motor loads first — well pump, then fridge, then furnace — while the generator is lightly loaded and has maximum surge headroom.
5. 5Add the steady loads last: lighting, electronics, chargers.

Step 4 is the one people get wrong. Surge headroom is whatever the generator is not already using. Start a fridge needing 2,200 watts of surge when the machine is at 90% of its running rating and it will bog down or trip. Start the same fridge first, when the generator is nearly unloaded, and it goes without complaint.

Load management during the outage

With a transfer switch, the circuit selection does most of this for you. With an interlock kit, it is entirely manual, and here is the discipline that works:

• Decide your standing set — the circuits that stay on: fridge, furnace, water, lighting. Add up their running watts from the wattage chart and make sure they total well under the generator's rating.
• Treat everything else as one-at-a-time. Microwave OR coffee maker OR toaster, never two. They each run for minutes, so this costs you nothing.
• Reserve headroom for cycling loads. A sump pump cycles unpredictably and needs its surge available whenever the pit fills — do not have that headroom borrowed by the microwave.
• Never run a machine flat out for days. The 80% derating we apply in sizing exists for this reason.

Shutting down

Reverse it: shed loads, switch back to utility (or main breaker on, generator breaker off, in that order), then shut the generator down and let it cool before refueling or covering it. If it is going back into storage for months, add fuel stabilizer first — that is the step that decides whether it starts next time.