Installing an Interlock Kit - What to Expect
Last verified: September 2026
An interlock kit is the budget-friendly way to power whole circuits from a generator — and, done right, a licensed electrician's job with the correct listed kit for your panel. Here's what to expect. Rather talk it through? My number is (330) 200-8042.
Installing an Interlock Kit, at a Glance
An interlock kit is a UL-listed metal plate fitted to your existing electrical panel that makes it mechanically impossible to have the main breaker and the generator breaker on at the same time — which prevents the generator from ever backfeeding the utility. It's popular because it's cheaper than a transfer switch and uses your existing breakers, so more circuits are within reach. The catch: it must be the correct listed kit for your exact panel and installed by a licensed electrician with a permit. You manage the load by hand, and the generator still runs outdoors, at least 20 feet from the house. There's a printable page-by-page version up top.
Common Questions
1 What is an interlock kit?
It's a UL-listed metal plate fitted to your existing electrical panel that makes it physically impossible to switch on the main breaker and the generator breaker at the same time. That mechanical block is what keeps the generator from ever backfeeding the utility lines.
2 Why is it cheaper than a transfer switch?
Because the hardware is a simple plate and a breaker rather than a separate labeled box of switches. You still pay for a licensed electrician and usually a permit — the savings are in the parts, not the labor.
3 Can I buy a plate online and install it myself?
No. It must be a UL-listed kit made for your exact panel brand and layout, and installing it means opening and modifying the panel — a licensed electrician's job, with a permit. A non-listed or wrong-fit plate is unsafe and, in most places, illegal.
4 How do I use it during an outage?
Start the generator outside and connect the heavy cord to the inlet. At the panel, turn the main breaker off, slide the interlock, and turn the generator breaker on — then bring your circuits on one at a time, staying within what the generator can deliver so you don't overload it.
5 What if there's no listed kit for my panel?
Then an interlock isn't your route, and that's fine — a transfer switch is the alternative. Never force a plate that isn't made for your panel. Ask the electrician early so you can plan around it.
6 Do I still have to worry about carbon monoxide?
Absolutely. An interlock makes the wiring safe, but the generator still runs outdoors, at least 20 feet from the house, exhaust pointed away from every window, door, and vent, with battery-backup CO alarms tested inside. The hookup never changes that rule.
Would You Rather I Just Help?
Deciding whether an interlock kit is right for you, confirming the pieces fit your panel, and lining up the electrician is exactly what I help with — with nothing to sell you. $99 flat for a visit, 30-day come-back-free.
Would you rather I just do this for you?
No shame in it — plenty of folks would rather hand it off, and that's what I'm here for. I'll come to your home, set it up right, and make sure it's working before I leave. Flat $99 per visit — no jargon, no upsell, and every visit is 30-day come-back-free.
Not a hardware job? I can often fix it remotely for $49 — a secure screen-share, up to 2 hours, that you watch the whole time and can end whenever (included free for $39/mo Support Plan members, and it counts toward the $99 if it turns out I need to come out).