Every fall in Whatcom County, the same thing happens: a windstorm rolls through, the trees come down, and the power goes with them. After the third or fourth outage, most homeowners start thinking about a generator. Good instinct — but how you connect that generator to your house matters enormously. Done wrong, it can kill a lineworker. Done right, you ride out the outage in comfort.
There are two code-compliant ways to do it: an interlock kit or a transfer switch. Here's the honest comparison — including the costs most contractors won't put in writing until they've already got you on the phone.
First, what NOT to do
No extension cords through windows. No backfeeding your panel through a dryer outlet with a homemade double-male cord — we've seen it, and it's terrifying. A generator connected wrong can energize the utility lines outside your house. That's how lineworkers die. Both options below prevent that. Anything else isn't an option.
The code is explicit about this, too. NEC Article 702.5 requires transfer equipment on every standby system, and it must be listed and designed so the two power sources can never connect to each other — not by accident, not by a forgotten breaker. A suicide cord meets none of that. An interlock kit or a transfer switch meets all of it.
Option 1: Generator interlock kit
An interlock is a simple mechanical device on your panel that makes it physically impossible for your main breaker and your generator breaker to be on at the same time. Generator on means utility off. No exceptions, no mistakes.
Installed cost: roughly $400–$850, per HomeGuide's 2026 cost guide — the kit itself runs $50–$150, plus the inlet box, breaker, cord, and a few hours of labor. It's the most affordable code-compliant route, because it uses the panel you already have.
Pros: Cheapest legal way to connect a portable generator. It uses your existing panel, and it lets you power any circuit in the house, up to your generator's capacity — you're choosing which breakers to leave on, not locked into a pre-wired handful.
Cons: It's manual. When the power goes out, you're hauling out the generator, plugging it in, and flipping breakers yourself — in the dark, possibly in the rain. And you're managing which loads run so you don't overload the generator.
There's also a catch worth knowing before you buy a kit online: the interlock must be listed for your exact panel model. The panel manufacturer's own kit, listed on the panel label, is the safe bet. Aftermarket kits that aren't listed for your panel can void the panel's listing and may not actually meet the UL 1008 requirements for transfer equipment. If your panel is older or off-brand and no listed kit exists for it, an interlock may not be an option at all — that's when a transfer switch is the right call.
Best for: Homeowners with a portable generator who don't mind a ten-minute setup during an outage.
Option 2: Transfer switch — manual or automatic
A transfer switch is a separate panel that sits between your utility feed, your generator, and your chosen circuits. A manual transfer switch means flipping one switch instead of juggling breakers. An automatic transfer switch, paired with a standby generator, does everything itself — the power drops, the generator starts, and your house is back up in under a minute while you never left the couch.
Installed cost: a manual transfer switch runs roughly $400–$1,300 installed (HomeGuide; Angi's July 2026 update puts typical installs at $1,200–$1,600). An automatic transfer switch for a standby generator runs $1,500–$4,000 installed, usually priced as part of the generator package — and a whole-house standby generator install runs about $7,000–$15,000 all-in.
Pros: Cleaner, simpler operation. A manual switch gives you one clear action instead of a breaker dance. The automatic versions are fully hands-off — and for anyone with medical equipment, a home office that can't go dark, or a sump pump that can't wait, that matters.
Cons: Costs more — especially a standby generator with an automatic switch, which is a real investment. And a manual transfer switch only powers the circuits wired to it, so you pick your essentials in advance.
Best for: Anyone who wants simplicity, has medical equipment or a home office that can't go dark, or just doesn't want to wrestle a portable generator in a windstorm at midnight.
What about the generator itself?
Portable generators — the kind from the hardware store — pair with interlock kits and manual transfer switches. Standby generators — permanently installed, running on natural gas or propane — pair with automatic transfer switches.
Size the generator to your actual loads, not to your wish list. A 7,500-watt portable covers the essentials: fridge, furnace fan, some lights, a few outlets. A whole-house standby can run everything. And remember the code's own rule for manual setups — NEC 702.4 says the homeowner selects the loads the system will run at one time. That's the load-shedding pattern almost every interlock install actually uses: refrigerator, furnace fan, a few outlets, lighting — and the EV charger only when other major loads are off.
One more thing people forget: the generator lives outside, always. Never in the garage, never under a window. Carbon monoxide kills more people during outages than the outage itself.
Cost at a glance
Interlock kit + inlet — Installed cost (2026 guides): $400–$850 — Operation: Manual — Best for: Portable generator, budget-first
Manual transfer switch — Installed cost (2026 guides): $400–$1,300 — Operation: Manual, one switch — Best for: Portable generator, simplicity
Automatic transfer switch + standby generator — Installed cost (2026 guides): $7,000–$15,000 total — Operation: Fully automatic — Best for: Hands-off backup, medical/home office
Costs are national guide ranges (HomeGuide, Angi, 2026) — your price depends on your panel, the number of circuits, and local labor rates. Permits add roughly $50–$250 depending on jurisdiction. Treat these as a sanity check, not a quote.
Permits and code
Generator connections require an electrical permit and inspection in Bellingham and Whatcom County, and the work has to meet NEC Article 702 requirements. This isn't a DIY project — it's the kind of thing that's either done right or dangerous. A licensed electrician also makes sure the install won't cause problems with your insurance later.
One timing note: Washington adopts the 2026 NEC on December 31, 2026. If you're planning a generator hookup, getting the permit pulled before year-end keeps things under the edition your electrician is already working to.
Bottom line
Want the most affordable safe backup power and don't mind manual setup? Interlock kit plus a portable generator. Want the power to just come back on by itself? Automatic transfer switch plus a standby generator. Either way, get it done before storm season — not during it. The week the wind takes the power out is the week every electrician in the county is booked solid.
Old Town Electric installs generator interlock kits, transfer switches, and standby generator connections across Bellingham and Whatcom County — code-compliant, permitted, and backed by our 1-year labor warranty. Call (360) 393-4135 for a quote.