Wind and ice storms can leave homes in our area without power for hours or even days. A generator can keep the fridge cold, the furnace running, the sump or well pump working, and the lights on. But how it connects to your house matters as much as the generator itself. Done wrong, it can start a fire, ruin the generator, or put the crews fixing the power lines in danger.
This guide covers the two main kinds of home generators, the safe ways to connect them, why a dryer outlet is never the answer, how to think about size and fuel, and what permits are involved in Washington and Oregon.
Portable or standby: two kinds of home generators
- Portable generators usually run on gasoline, propane, or both. You roll one outside and start it when the power goes out. They cost less and can run a handful of essentials, either plugged straight into the generator or connected to the house through a transfer switch or interlock kit.
- Standby generators are installed permanently outside, like an air conditioner, and run on natural gas or propane. When the power goes out, an automatic transfer switch starts the generator and switches your circuits over within seconds, even if no one is home. When utility power returns, it switches back.
Portable is a good fit if you mainly want to save food, keep the heat on, and charge phones through the occasional outage. Standby makes more sense if someone relies on medical equipment, you work from home, you travel a lot, or outages where you live tend to run long.
Why a generator can’t just plug into the house
Some people power the house by running a cord with a plug on both ends from the generator into a dryer outlet or wall outlet. This is called backfeeding, and it’s one of the most dangerous things you can do with a generator.
- It can hurt or kill line workers. Your house is still connected to the power lines. Generator power can flow back out through your meter to the transformer serving your house, which raises it to the much higher voltage on the lines. A crew working on a line they believe is dead can be seriously hurt or killed.
- It can start a fire. Household outlets and wiring aren’t built to be fed this way, and the generator can push more current through that circuit than it can handle.
- It can wreck the generator. If utility power comes back while the generator is still connected, the generator and what’s plugged in can be badly damaged.
- The cord itself is a shock hazard. With one end plugged in, the bare prongs on the other end are live.
Utilities in our area, including PGE and Clark Public Utilities, tell customers never to plug a generator into a household outlet. Until you have a proper connection, plug appliances directly into the generator with outdoor-rated extension cords.
Safe ways to connect a generator to your home
Every safe connection does the same job: it disconnects your house from the power lines before the generator can feed it, so the two can never be connected at the same time. The common options:
- Manual transfer switch. A small panel next to your main panel. Your most important circuits, such as the furnace, fridge, a few lights, and any pumps, are moved onto it. In an outage, you plug in the generator and flip those circuits over to generator power.
- Generator interlock kit. A metal plate on your main panel that physically keeps the main breaker and a generator breaker from being on at the same time. It lets the generator feed any circuit in the panel, and you choose which breakers to turn on so you don’t overload it. The kit must be made and listed for your exact panel model.
- Power inlet box. A weatherproof outdoor connection on an outside wall, wired to the transfer switch or interlock. One heavy-duty generator cord runs from the generator to the inlet, with no cords through windows or doors. Inlets commonly come in 30-amp and 50-amp versions to match the generator.
- Automatic transfer switch. Used with standby generators. It senses the outage, starts the generator, switches over, and switches back when the power returns. It can cover a few essential circuits or the whole house.
Simply turning off your main breaker and backfeeding through an outlet is not a safe substitute. One forgotten breaker, or someone flipping the main back on, is all it takes.
How big a generator do you need?
- Starting power counts. Anything with a motor, like a well pump, sump pump, fridge, furnace blower, or heat pump, needs a burst of extra power to start. The generator has to handle those surges, not just the steady load.
- Essentials or the whole house. Many homes do fine backing up just the furnace, fridge and freezer, some lights and outlets, the internet router, and any pumps. Whole-house backup takes a much larger generator, especially with electric heat, a heat pump, an electric range, or an electric water heater.
- Load management can stretch it. Some standby systems automatically switch off a big load, like a water heater, while other loads run, so a smaller generator can cover more of the house.
- Real numbers beat rules of thumb. We look at what you want to run and the generator’s rating, then match the connection to it.
Fuel at a glance
- Gasoline is common on portables and easy to find, but it doesn’t store well and needs frequent refills in a long outage.
- Propane stores well in a tank and is used by many standby and dual-fuel portable generators. Tank size sets how long you can run.
- Natural gas feeds many standby generators where the home already has gas service, so there’s no refueling. The gas meter and piping have to be big enough for the generator.
Where the generator sits matters
Generator exhaust contains carbon monoxide, which you can’t see or smell. The U.S. Consumer Product Safety Commission says to run portable generators outside only, at least 20 feet from the house, with the exhaust pointed away from doors, windows, and vents, and never in a garage, carport, or on a porch. Standby units go outdoors with the clearances the manufacturer and local code require. Either way, keep working carbon monoxide alarms inside. We plan the inlet location so the generator can sit well away from the house and the cord reaches without crossing a doorway.
Permits and inspection in Washington and Oregon
Connecting a generator to your home’s wiring is permitted electrical work in both states, whether it’s a transfer switch for a portable or a full standby install.
- In Washington, permits and inspections come from the Department of Labor & Industries (L&I), or from your city if it runs its own electrical inspections.
- In Oregon, the permit comes through your local building department. The state’s Building Codes Division notes that code requires a transfer switch or other safety device to prevent backfeeding.
- Your utility may want to know. PGE asks customers to let them know about a permanently installed generator, and Clark Public Utilities requires a “break-before-make” transfer switch on permanent generators, which disconnects from the grid before the generator connects.
Cascadia Power pulls the permit, does the install, and coordinates the inspection, so the work is documented for you, your insurance company, and any future buyer.
What Cascadia Power does
We don’t sell or service generators. We handle the electrical connection: the transfer switch or interlock, the inlet, the wiring, and the permit.
- Recommend the simplest safe connection for your panel and your needs: an interlock kit, a manual transfer switch, or an automatic transfer switch for a standby unit.
- Install the inlet, transfer equipment, and wiring, sized to your generator and to code.
- Help you pick which circuits to back up, and label everything so it’s easy to use in the dark.
- Wire standby generators as well as connections for portable generators.
- Show you how it works. Before we leave, we walk you through switching to the generator and back.
After planning, we do as much prep as we can ahead of time, like confirming the right interlock or transfer switch for your panel and staging materials, so your power is off as briefly as possible on install day.
What to send us before a visit
- A clear photo of your open panel, showing the breakers and main breaker size, plus the label inside the door if it’s readable.
- Your generator’s model or label, or the size you’re considering.
- What you want running in an outage, such as heat, pumps, the fridge, medical equipment, or the whole house.
- Where the generator would sit, and roughly how far that is from the panel.
- Your fuel, whether natural gas, a propane tank, or gasoline.
On-site estimates for generator connections are free. If you decide to go ahead, a 50% deposit when you sign gets your job on the schedule.
Serving Southwest Washington and Oregon
Cascadia Power is a licensed, bonded, and insured electrical contractor based in Ridgefield, Washington. We help homeowners across Southwest Washington and Oregon, including the Portland metro area, connect backup power safely, from an interlock kit for a portable generator to a whole-house standby system.
Ready to connect a generator the safe way?
Send a photo of your panel and tell us what you want to keep running during an outage. We’ll recommend the simplest safe way to hook it up.
Have a question first? Contact us.