Every hurricane season, the same search spikes: how to hook up a generator to my house — and the top of that demand curve is exactly when people make the one mistake in home backup power that can kill someone who isn’t even in their house.
So let’s be direct about the destination before the map: there are four safe, legal ways to connect a portable generator, ranging from $80 extension cords to a $1,500 installed transfer switch — and one infamous shortcut, the “backfeed” through a dryer or wall outlet, that is illegal everywhere, banned by every code, and lethal often enough that utilities publish warnings about it every storm season.
This guide explains all four legitimate options — what each costs, what each can and can’t power, and which fits your situation — plus what the professional installation involves for the panel-connected options, so you can buy the right hardware and hire the right hour of electrician time. What it deliberately doesn’t do is teach panel wiring: that part is licensed-trade work, legally and for reasons this article makes vivid.
First: Why Backfeeding Kills (Read Even If You’d Never)
The shortcut circulating in every outage forum: plug the generator into a dryer outlet or wall receptacle with a homemade double-male cord — grimly nicknamed a suicide cord — and “power the whole panel.”
What’s actually wrong with it, in order of severity:
- It can electrocute utility line workers. Without a transfer switch isolating your home, your generator’s power flows backward through your meter into the neighborhood’s lines — where your home’s transformer steps it up to thousands of volts. Crews repairing “dead” lines have been killed this way. This is why backfeeding isn’t a code technicality; it’s the closest thing home wiring has to a loaded weapon.
- It can kill you at the cord. A double-male cord has exposed live prongs the moment the generator runs. One slip while connecting is a 240V handshake.
- It energizes your home with zero protection — no breaker coordination, no isolation, and when grid power returns while your generator is connected, the collision can destroy the generator, your panel, or start a fire.
- It voids your insurance and violates the law. After the fire or the injury, the unpermitted backfeed is what the investigation finds [→ /standby-generators/how-does-a-standby-generator-work/].
Every safe option below exists to make the same thing impossible: your house being connected to the grid and the generator at the same time.
Option 1: Extension Cords Only — $50–$150, Zero Installation
The simplest legal setup: the generator outside, quality cords through a window or door to individual appliances.
What it does well: powers the fridge, a freezer, lamps, fans, chargers, TV, a space heater — the plug-in essentials — with no electrician, no permit, no installation, today [→ /portable-generators/what-size-generator-runs-refrigerator/].
Its hard limits: anything hardwired is unreachable — furnace, well pump, most sump pumps, central AC, ceiling lights. And cord quality is not a detail: 12-gauge outdoor-rated minimum (10-gauge past 50 ft), fully uncoiled (coiled cords under load build heat), routed so doors/windows don’t pinch them.
Best for: renters, rare-outage households, mini-fridge-and-Wi-Fi missions, and the first outage before you install a better option.
Option 2: Generator Interlock Kit — $400–$900 Installed (The Value King)
An interlock is a simple sliding metal plate on your electrical panel plus a dedicated generator inlet box on the exterior wall. The plate makes it mechanically impossible to switch on the generator’s breaker unless the main utility breaker is off — one power source at a time, enforced by metal.
How it’s used (after professional installation): grid fails → you roll out the generator, connect one heavy cord to the exterior inlet, start it → at the panel, flip the main OFF, slide the interlock, flip the generator breaker ON → then turn on only the circuit breakers your generator can carry. Your hardwired loads — furnace, sump pump, well pump, real lighting — are now reachable, which is the whole upgrade [→ /portable-generators/best-portable-generators-home-backup/].
Honest trade-offs: it feeds the whole panel with no automatic load limiting — you are the load management, flipping breakers wisely and living within your generator’s watts [→ /portable-generators/generator-wattage-chart/]. The kit must be listed for your exact panel model (a code requirement, not pedantry), some older panels have no compliant kit available, and a permit + licensed electrician are required essentially everywhere — the installation touches your service panel, which is precisely the work this site doesn’t teach and your jurisdiction doesn’t allow unlicensed [→ /installation-costs/generator-permit-requirements/].
Best for: the best capability-per-dollar in portable backup — the standing recommendation of this silo for owned homes [→ /installation-costs/interlock-kit-vs-transfer-switch/].
Option 3: Manual Transfer Switch — $500–$1,500 Installed (The Curated Panel)
A manual transfer switch is a small dedicated sub-panel mounted beside your main panel, pre-wired (by your electrician) to your chosen 6–10 essential circuits. During an outage: connect the generator to the inlet, start it, and flip the transfer switch from LINE to GEN — those circuits now draw from the generator, mechanically isolated from the grid.
Why choose it over an interlock: it’s the more idiot-proof instrument — only the pre-selected circuits can load the generator, so there’s no 2 a.m. arithmetic about which breakers to flip, and guests/family can operate it safely. Many models include wattage meters that show your load in real time, which turns load management from guesswork into a glance.
Honest trade-offs: costs more than an interlock for less flexibility — circuits are chosen once, at install, and the “I forgot the garage freezer circuit” regret is real [→ /standby-generators/whole-house-vs-partial-home-backup/]. Choose the circuits during a walkthrough, not from memory.
Best for: households prioritizing simplicity and error-proofing over flexibility — and homes where multiple people may need to run the system.
Option 4: Manual Transfer Panel + Tri-Fuel on the Gas Line — $1,500–$3,000 All-In (The Portable Endgame)
Combine Option 2 or 3 with a tri-fuel portable connected to your natural gas line via a professionally installed quick-connect, and you’ve built the poor man’s standby system: hardwired circuits reachable, runtime effectively unlimited (no gasoline logistics), for a fifth of a standby install’s price. The remaining gap versus true standby is automation — you still start it and flip the switches — and output derates ~20–25% on natural gas [→ /portable-generators/best-portable-generators-home-backup/].
Best for: natural-gas homes with real outage exposure that aren’t ready for the $10,000+ standby conversation [→ /standby-generators/are-whole-house-generators-worth-it/].
The Options, Side by Side
| Cords only | Interlock | Manual transfer switch | Interlock/switch + tri-fuel NG | |
|---|---|---|---|---|
| All-in cost | $50 – $150 | $400 – $900 | $500 – $1,500 | $1,500 – $3,000 |
| Installation | None | Electrician + permit | Electrician + permit | Electrician + permit + gas fitter |
| Hardwired loads (furnace, pumps) | ✗ | ✓ (whole panel) | ✓ (chosen circuits) | ✓ |
| Load management | Physical (what’s plugged in) | You, at the breakers | Built-in (pre-selected) | Per base option |
| Error-proofing | High | Moderate — requires discipline | High | Per base option |
| Runtime limit | Fuel on hand | Fuel on hand | Fuel on hand | Effectively unlimited |
The Outdoor Setup Ritual (The Part That IS Yours to Do)
Whatever connection you own, the operating discipline is identical — and this part kills more people than wiring does:
- Position: outside, 20+ feet from any window, door, or vent, exhaust pointed away from the house — never a garage (open door included), never a porch, never a basement. Carbon monoxide from bad generator placement is the leading cause of post-storm deaths in America, and a CO-shutoff model is a backstop, not permission [→ /portable-generators/portable-generator-safety-carbon-monoxide/].
- Weather protection: run it under a purpose-built generator tent/cover or open canopy — dry, but never enclosed [→ /portable-generators/run-generator-in-rain/].
- Connect cords before starting; start before loading. Let it stabilize, then add loads biggest-surge-first [→ /portable-generators/what-size-generator-runs-refrigerator/].
- Refuel cold: shut down, wait several minutes, then pour. Gasoline meeting hot exhaust is an ER genre.
- Secure it: generators vanish during regional outages — a ground anchor and lock cost $40.
- When grid power returns (interlock/switch owners): reverse the sequence — generator breaker off, interlock slid back / switch to LINE, main on, then shut the generator down after a brief no-load cooldown.
Frequently Asked Questions
Can I connect a generator to my house without a transfer switch? Legally, only via extension cords to individual appliances. Any connection to your home’s wiring requires a transfer switch or interlock — the devices that make grid/generator coexistence impossible. The dryer-outlet shortcut is illegal everywhere and lethal to line workers.
How much does it cost to hook up a portable generator to a house? Extension cords: $50–$150. Interlock kit installed: $400–$900. Manual transfer switch installed: $500–$1,500. Adding a natural-gas quick-connect for a tri-fuel unit: $300–$800 more.
Do I need a permit to install an interlock or transfer switch? In nearly every US jurisdiction, yes — it’s service-panel work requiring a licensed electrician and inspection. The permit is also what keeps your insurance valid after any incident [→ /installation-costs/generator-permit-requirements/].
Can my portable generator run my furnace? Through an interlock or transfer switch, yes — a gas furnace’s blower draws only 500–800 running watts. This single hardwired load is the reason cold-climate homes outgrow the cords-only setup.
What size cord do I need from the generator to the inlet box? The heavy generator-to-inlet cord is typically a 30A (L14-30) or 50A (14-50/SS2-50) cord matched to your inlet and generator outlet — 10-gauge minimum for 30A runs, heavier for 50A. Buy the listed cord for your hardware, keep it short as practical, and never improvise adapters onto dryer outlets.
Is an interlock as safe as a transfer switch? A code-compliant, panel-listed interlock professionally installed — yes, both enforce the same principle mechanically. The transfer switch adds error-proofing (pre-limited circuits); the interlock adds flexibility. Safety is equivalent; discipline requirements differ.
The Bottom Line
Four legal doors into your house: cords for the plug-in basics, an interlock for whole-panel flexibility at the best price, a manual transfer switch for foolproof curated circuits, and the tri-fuel-on-gas configuration that turns a portable into a near-standby. Pick by budget and temperament, hire the licensed hour for anything touching the panel, and run the outdoor ritual like the checklist it is. And the fifth door — the double-male cord into the dryer outlet — isn’t a door at all: it’s the one move in home backup that can kill a stranger up the street, and the entire reason the other four exist.