Why Install a Generator Interlock Kit?

With a professionally installed interlock kit you get:

• The ability to run hard-wired circuits — well pumps, furnaces, lighting and refrigeration — that extension cords can never reach.
• A mechanical safeguard that makes it impossible to back-feed the utility grid, protecting your family, your equipment and utility line workers.
• Whole-panel flexibility at a fraction of the cost of an automatic standby generator or transfer switch system.

Key Terms You Should Know

• Interlock kit: A mechanical slide plate on your panel that physically prevents the main breaker and the generator breaker from being on at the same time — the heart of safe manual backup power.
• Back-feed: Electricity flowing from a generator out onto utility lines. It can electrocute line workers and destroy your generator; an interlock (or transfer switch) is the code-required protection against it.
• Generator inlet box: A weatherproof, recessed male receptacle mounted outside your home where the generator cord plugs in — commonly a NEMA L14-30 (30 A) or CS6375 / L14-50 (50 A) configuration.
• Interlock vs. transfer switch: A manual transfer switch feeds a fixed set of pre-selected circuits; an interlock gives you access to every circuit in the panel (managed manually) and usually costs significantly less to install.
• Listed / panel-matched: Interlock kits are only code-compliant when listed for your exact panel. Generic or homemade interlocks will fail inspection.

Frequently Asked Questions

• Is an interlock kit legal in California? Yes — when the kit is listed for your panel, installed with a proper back-feed breaker and inlet, and permitted and inspected. That is exactly how we install every system.
• Interlock kit or transfer switch — which should I choose? An interlock is the most economical option and lets you power any circuit in your panel. A transfer switch or automatic standby system costs more but adds convenience. We’ll help you compare both for your home and budget.
• What size generator do I need? Most homes do well with a 7,500–12,000 W portable generator on a 30 A or 50 A inlet. We’ll size it to the loads you actually want to run — well pump, furnace, refrigerator, lights and more.
• Can I run my whole house on it? You can access every circuit, but a portable generator can’t run everything at once. We label your panel so you know exactly what to switch on during an outage.
• Can I install an interlock kit myself? Interlock installation involves working inside a live panel and requires a permit in Auburn / Placer County. A professional installation protects your safety, your insurance coverage and your home’s resale paperwork.
• How long does installation take? Most interlock kit and inlet box installations are completed in a single visit, typically 2–4 hours.