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A listed interlock so the main and the generator breaker cannot be on together
An interlock is the mechanical answer for a portable generator on many residential panels: the main has to be off before the generator breaker can turn on. It is not a transfer switch, and it is not legal on every panel. The kit has to be listed for the equipment you have.
Listed for this panel
The kit is specific to the enclosure. A sliding plate from a different panel is not a listed interlock.
The inlet still belongs
The outdoor connection is generator inlet. The interlock is how that inlet is allowed to feed the panel.
When it is the wrong method
Selected circuits, or a standby unit that should start itself, is transfer switch. The family overview is backup power.
A generator interlock has to be listed for your exact panel
An interlock is the low-cost, code-legal way to feed a house from a portable generator, but only when the kit is listed for that specific panel and the breaker layout allows it. It is a whole-panel solution with real constraints, not a universal part.
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Panel-specific
The listed kit has to match the panel brand and model, and the generator breaker has to land where the interlock requires. A generic bracket on the wrong panel is not a legal install.
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Whole panel, not selected circuits
An interlock energizes the whole panel from the generator — you manage load by which breakers you leave on. A defined set of always-on circuits is a transfer switch instead.
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Backfeed protection is the point
The interlock exists so the main and the generator breaker can never be closed together. Any workaround that defeats it creates the very hazard the kit exists to prevent.
When an interlock isn’t the right job
A listed kit on this panel is this job. The outdoor inlet alone, or an automatic transfer switch, are not.
You only need the outdoor connection discussed
That is generator inlet — and it still needs this interlock or a transfer switch.
You want automatic transfer or a defined subset of circuits
That is transfer switch. An interlock is not a transfer switch.
Generator interlock questions
Is this the same as a transfer switch?
No. It is not a transfer switch. A listed interlock is a mechanical slide on this panel. Selected circuits or automatic transfer is transfer switch.
Will it fit my panel?
Only if a kit is listed for that enclosure and the generator breaker can sit where the kit requires. We look at the panel before anyone orders hardware.
Do I still need an inlet?
Yes. The outdoor connection is generator inlet. The interlock is what makes that inlet legal.
Can I run the whole house?
Usually no. A portable generator through an interlock still has to be sized to what you actually turn on. Which circuits matter is the backup power conversation.
Are generator interlocks legal?
A listed interlock kit for that panel, permitted, is how many houses run a portable generator so power cannot go back out to the street. The inspector has to see it.
Which is better, an interlock or transfer switch?
An interlock is cheaper and uses the existing panel. A transfer switch isolates selected circuits. We pick from the generator and the loads you want on.
Still not sure it is the right job? Call (279) 972-9272 — available 24 hours.
Serving 19 communities across the Sacramento area
Litel Electric serves homeowners throughout all 19 communities in our service area — from Davis and Woodland to Roseville, Folsom, and Elk Grove.
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Tell us what is happening, or what you are planning. We read the details, tell you what else we need to know, and explain the next step before anything is scheduled.
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You send the problem or the plan, with the address if you have it.
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We reply with what it involves and what has to be seen in person.
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Nothing is scheduled, and nothing is priced, until the equipment has been looked at.
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