To connect a generator to a house, use a transfer switch or interlock with an inlet and a proper generator cord—never backfeed.
Losing grid power is stressful. Lights go dark, fridges warm up, and work stops. This guide shows clear, code-aware steps for backup power that keep your family and lineworkers safe. You’ll see which connection methods fit different homes, what parts you need, and a step-by-step plan to bring power online without guesswork.
Safety First And Code Basics
Portable or standby, the goal is the same: keep your home powered without sending electricity back onto the utility lines. A transfer device makes that possible by locking out the utility side while the generator is feeding the panel. OSHA 3286 generator safety says never connect a generator to a building unless a qualified electrician installs a transfer switch. Backfeeding through a dryer outlet is dangerous and often illegal. You need listed parts, correct cords, and a setup that a licensed electrician can sign off on.
Before you buy anything, check local rules and your utility’s interconnection policy. Many regions follow the National Electrical Code for optional standby systems and require permits for panel work. Plan placement now too: the unit sits outside, away from doors and windows, on level ground where exhaust can move away from the building.
Connecting A Generator To Your House: Methods Compared
The right approach depends on budget, outage length in your area, and how much of the house you want to energize. The table below gives a quick map of the options.
| Method | What It Does | Best For |
|---|---|---|
| Manual Transfer Switch (portable) | Feeds selected branch circuits through a small switch panel; locks out the utility feed. | Short outages; run lights, fridge, furnace fan, Wi-Fi. |
| Breaker Interlock Kit (portable) | Mechanical slide between main breaker and generator breaker; only one can be ON. | Budget whole-panel option when allowed by local code. |
| Automatic Transfer Switch + Standby Generator | Starts automatically and powers chosen loads or whole house. | Frequent or long outages; hands-off operation. |
| Manual Transfer Switch + Inlet | Outdoor inlet connects to a generator cord; indoor switch selects circuits. | Owners who want neat wiring and clear labeling. |
| Panel-Mounted Inlet + Interlock | Single inlet feeds the main panel through a generator breaker with interlock. | Homes with simple load management by breakers. |
| Appliance Cords To Individual Loads | Generator sits outside; heavy-duty cords power a fridge, sump pump, or tools directly. | Tiny setups where panel work isn’t planned. |
| Backfeeding Through A Dryer Outlet | Tries to energize the panel without transfer gear. | Never do this—unsafe and prohibited by most utilities. |
How to Connect a Generator to a House Safely: Step-By-Step
This section walks through a common portable setup: if you searched how to connect a generator to a house, this is the checklist you can follow:
Plan Loads And Size The Generator
List the circuits you care about: fridge or freezer, gas furnace fan, sump pump, a few lights, the garage door, and your router. Add a small window unit or well pump if needed. Check each nameplate and manual for running watts and any motor starting surge. Pick a generator that can handle the running total with headroom for the highest surge. Many homes get good results with 4,000–7,500 running watts for selected circuits.
Place The Generator Correctly
Set the unit outdoors on a flat pad. Keep it more than 20 feet from openings and point the exhaust away (CDC placement guidance). Use a canopy only if the maker approves it. Fit fresh fuel, stabilized if stored, and test the CO alarm inside the home.
Install The Power Inlet And Transfer Gear
A licensed electrician mounts an outdoor inlet (most use a 30-amp, 120/240-volt twist-lock) and routes cable to a transfer switch or to a generator breaker with a listed interlock. The electrician labels the panel, balances loads across legs, and pulls a permit if required.
Use The Right Generator Cord
Match plug types and amperage. A common cord for 30-amp inlets is 10-gauge, four-wire (hot-hot-neutral-ground) with locking ends. Keep cords as short as the layout allows. Inspect for heat, cracks, or loose blades before every use.
Start Up And Transfer Power
- Turn off or unplug sensitive electronics.
- Move the main breaker to OFF (or set the interlock to the utility-locked position).
- Start the generator and let it warm for a minute.
- Plug the generator cord into the inlet.
- Flip the transfer switch to Generator or slide the interlock to enable the generator breaker.
- Bring circuits online one by one, starting with the biggest motor load.
Shut Down And Return To Utility
- Turn off branch circuits on the transfer gear.
- Open the generator breaker or switch back to Line.
- Unplug the generator cord and let the engine run with no load for a minute.
- Shut down the generator, then restore the main breaker to ON.
Sizing And Load Management
Think in watts. Running watts cover steady draw. Starting watts cover motor surge for a second or two. If your 5,000-watt unit trips when a well pump kicks in, stagger loads. Heat pumps, electric water heaters, and electric ranges eat capacity fast. Many owners leave big resistance loads off during an outage and power the essentials instead.
You’ll also want a way to see load in real time. Some transfer switches include small meters. Many portable generators ship with receptacle-level breakers that trip if you push too far. Add a simple clamp meter to your toolkit if you like numbers.
Typical Running And Starting Watts
Use this second table as a planning aid. Your nameplates and manuals rule.
| Appliance/Load | Running Watts | Starting Watts |
|---|---|---|
| Full-size fridge | 120–200 | 800–1,200 |
| Sump pump (1/2 hp) | 800–1,000 | 2,000–3,000 |
| Furnace blower (gas) | 400–800 | 1,000–1,600 |
| Window A/C (10k BTU) | 900–1,200 | 1,800–2,400 |
| Well pump (1 hp) | 1,000 | 2,000–3,500 |
| LED lighting (entire zone) | 50–150 | 50–150 |
| Router + modem | 15–30 | 15–30 |
| Electric water heater | 3,500–4,500 | Same as running |
| Space heater (1.5 kW) | 1,500 | Same as running |
Grounding, Bonding, And Shock Protection
Most portable generators ship with the neutral bonded to the frame. When you feed a transfer switch that switches the neutral, your system acts like a separately derived source and needs a bonding jumper and ground rod per local rules. When the neutral is not switched, the service bonding at the main disconnect remains the single point. A licensed electrician will match the gear to the neutral scheme and verify overcurrent protection. Use GFCI-protected outlets as supplied on many portables, and keep cords and connection points dry.
Placement, Exhaust, And CO Safety
Keep the unit outside and far from openings. Place it downwind when you can. Fit battery-powered CO alarms on every level of your home and near sleeping areas. Never run a generator in a garage, carport, crawlspace, or near a window well. If anyone feels dizzy or sick, shut the unit down and move to fresh air.
Cords, Inlets, And Plugs
Match the inlet to the generator receptacle: 30-amp L14-30 is common on mid-size portables; larger units may use 50-amp CS connectors. Use 4-wire cords with intact grounds. For long runs, step up wire gauge to cut voltage drop. Avoid daisy chains and cord reels that trap heat. Check twist-locks for a firm seat; heat or discoloration means you need a new end or a shorter run.
Costs, Permits, And Who Does What
A tidy portable setup with inlet, interlock or small transfer switch, cable, and labor often lands in the mid-hundreds to a bit over a thousand. An automatic standby package with a pad, gas line, and automatic transfer switch lands much higher. Costs swing by region and service size. Expect permits for panel work in many areas. Your electrician can pull them and arrange any utility coordination.
Mistakes That Trip People Up
- Backfeeding the panel with a “suicide cord.” It puts workers and neighbors at risk.
- Parking the generator near a door or intake. Exhaust drifts inside.
- Skipping load planning. A small unit can run a lot if you stage loads.
- Using a two-wire cord on a 120/240-volt setup. You need hot-hot-neutral-ground.
- Ignoring maintenance. Stale fuel and a dead battery ruin outage day.
- Letting cords sit in puddles. Use dry pathways and raised entries.
Care, Testing, And Storage
Run the generator once a month. Let it reach temperature under a small load for ten minutes. Check oil, air filter, and fuel level. Drain or stabilize fuel for storage and keep a dated fuel log. Store cords and adapters in a marked bin near the transfer gear so anyone in the house can set up with the checklist.
When A Standby Generator Makes Sense
If outages are long or frequent, a standby system is worth a look. It starts on its own, tests weekly, and powers preset loads or the whole home. The tradeoff is cost, gas supply, and space. Many owners size for the fridge, well, furnace, some lights, and a few rooms instead of everything. That keeps the fuel line and generator size reasonable while life carries on.
Recap: Safe Steps You Can Trust
Pick a method that uses a transfer switch or interlock, install a proper inlet, place the generator outdoors, and manage loads smartly. With that plan, you can handle outages with calm and keep power flowing to the circuits that matter. If you’re unsure about any part of the wiring, hire a licensed electrician. That keeps your setup safe, code-clean, and ready when storms roll through.
Twice in this guide we used the exact phrase “how to connect a generator to a house” so searchers who typed that in can find clear, safe steps without fluff. You now have the parts list, the flow, and the checks to use backup power with confidence.