Never backfeed
A "suicide cord" (a cord with a plug on both ends) pushed into a wall outlet sends generator power into your panel. If the main breaker is on, it keeps going: out through the meter to the transformer, which steps it up to the voltage on the street lines. A lineworker repairing the outage can be killed by your generator. Don't buy, make or borrow one.
Option 1: extension cords
The simplest safe way, and fine for a fridge, a freezer, lights and phone chargers.
- Use heavy-duty outdoor cords rated for the load, run from the generator to each appliance.
- Keep the generator at least 20 feet from the house, outdoors, exhaust away from windows and doors.
- The catch: hard-wired things (furnace fan, well pump, sump pump on a hard-wired circuit) can't plug in.
Option 2: inlet and transfer switch or interlock
An electrician installs an outdoor inlet (a weatherproof socket for the generator cord) and one of:
| Transfer switch | Interlock kit | |
|---|---|---|
| What it is | A small panel next to the main one, with a switch per chosen circuit | A plate on the main panel that lets the generator breaker on only when the main is off |
| What it powers | The 6–10 circuits you picked in advance | Any circuit in the panel, within the generator's size |
| In an outage | Flip the chosen circuits to "generator" | Main off, generator breaker on, then circuits on one at a time |
Either way, the grid and the generator can never be connected at the same time. That's the whole point, and it's why this is a job for a licensed electrician, not a weekend project.
In an outage: start the generator outside, 20 feet away; plug the cord into the inlet; switch over as the label on your switch or panel says; turn circuits on one at a time, watching the generator's load.
Power stations
The same rules apply: cords, or an inlet and transfer switch. Two differences:
- No exhaust. A power station can sit indoors, right by the panel or the fridge.
- Usually 120V only. One unit powers 120V circuits; a 240V well pump or dryer needs a 240V-capable unit or two linked together. EcoFlow's Smart Home Panel, for example, switches up to 10 circuits, 120V from one DELTA Pro and 240V from two, and must be installed by a licensed electrician and inspected.
How big a unit you need: what size power station.
Sizing and the next step
- What size generator do I need adds up running and starting watts.
- Power station vs generator vs solar compares the three for outages.
- The home backup guide sizes a battery system that runs the house silently in an outage.
Questions people ask
Can I plug a generator into a wall outlet?
No. It's called backfeeding: power goes through your panel and out to the utility lines, where the transformer steps it up to high voltage, which can electrocute lineworkers fixing the outage. It also bypasses your breakers. Use cords or a transfer switch.
Do I need an electrician to connect a generator to my house?
For anything wired into the panel, yes. A transfer switch is installed next to the main panel by a licensed electrician, usually with a permit. Extension cords to individual appliances need no electrician.
How far from the house should a generator be?
At least 20 feet, outdoors only, with the exhaust pointed away from windows, doors and vents (CPSC). Never in a garage, basement or shed, even with the door open, and have working carbon monoxide alarms on every level.
Can a portable power station power my house?
Some circuits, through a transfer switch or the maker's home panel. Most single units are 120V: EcoFlow's Smart Home Panel runs 120V circuits from one DELTA Pro (3,600 W) and needs two for 240V (7,200 W). It runs indoors with no exhaust, which is the big advantage.
Transfer switch or interlock kit?
Both stop the grid and generator connecting at once. A transfer switch powers a set of chosen circuits; an interlock is a plate on the main panel that lets you feed the whole panel, turning circuits on one by one. An electrician will tell you which your panel allows.
Sources
- Transfer switch for generators (backfeeding, what a transfer switch does, licensed electrician) CPWR, The Center for Construction Research and Training
- CPSC warns of generator, carbon monoxide and fire hazards ahead of hurricane season (20 feet, CO alarms) US Consumer Product Safety Commission
- Power outages: generator safety Ready.gov (FEMA)
- EcoFlow Smart Home Panel user manual (licensed electrician and local inspection; 10 circuits; 120V with one DELTA Pro, 240V with two) EcoFlow
Every number on this page comes from these sources. Spotted something out of date? Tell me.
Size it for your place
A few taps and the guide works it out for your situation and your winter sun.