Backyard Gear Pro

Best Generator Transfer Switches & Interlock Kits for Home Backup (2026)

By the Backyard Gear Pro Editorial Team · How we test & rank

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Buying a generator is only half the job if you want it to power your home's wiring instead of just a few extension cords. Backfeeding through a wall outlet is dangerous — it can energize outside lines and shock utility workers — and it's illegal in most areas. A transfer switch or interlock kit is the only safe, code-compliant way to connect a portable generator to your panel, and nearly everywhere requires a licensed electrician to install one.

The two main hardware options are a dedicated transfer switch (a separate box with its own breakers for the circuits you want to power) and an interlock kit (a mechanical plate that lets one generator breaker safely swap in for your main breaker in your existing panel). Below we compare real options in both categories, plus the power inlet box some setups need. If you haven't sized your generator yet, start with our what size generator do I need guide — the amperage of your switch has to match what your generator can actually supply, and our best portable generators and best quiet portable generators roundups cover the generators themselves.

We're linking to Amazon search results rather than specific listings, since exact models, prices, and availability change constantly — use these picks as a shortlist to compare current listings and specs yourself before buying, and confirm compatibility with your panel and local code with a licensed electrician before you do.

How we picked: We compared transfer switches and interlock kits by amperage rating, circuit count, installation type (indoor panel-mounted vs. outdoor pre-wired), and compatibility across common panel brands, prioritizing well-known manufacturers with strong parts and support availability. None of this replaces a licensed electrician's code- and panel-specific guidance.

At a glance

#PickWhy it stands outPrice
Reliance Controls 31406CRK (30-Amp, 6-Circuit Indoor Transfer Switch)Top Pickoverall transfer switch for essential circuits - Covers the circuits most households actually need during an outage — fridge, sump pump, furnace blower, some lightsCheck Amazon
Reliance Controls TF151W (Pro/Tran 2, 30-Amp 10-Circuit Transfer Switch)Runner-upcovering more circuits on a 30-amp generator - 10 circuits instead of 6, so more of a household's essentials fit on one switchCheck Amazon
Reliance Controls 310CRK (Pro/Tran, Outdoor-Mounted 30-Amp Transfer Switch)Best Valuemounting outside without opening up the main panel - Pre-wired outdoor box mounts near the meter, which some electricians prefer over opening the main panelCheck Amazon
Champion Power Equipment 50-Amp Transfer Switch KitAlso greathigher-output generators and larger circuit counts - 50-amp rating matches larger portable and dual-fuel generators that outgrow a 30-amp switchCheck Amazon
Siemens Generator Interlock Kit (for compatible Siemens/Murray load centers)Also greatlower-cost alternative when your panel supports it - Costs significantly less than a dedicated transfer switchCheck Amazon
Reliance Controls PB30 (30-Amp Power Inlet Box)Also greatpower inlet box to pair with an indoor-mounted switch - Needed alongside an indoor transfer switch like the 31406CRK or TF151W, since those don't include an outdoor inletCheck Amazon

The picks in detail

Reliance Controls 31406CRK (30-Amp, 6-Circuit Indoor Transfer Switch)

Top Pick

9.6/10Editor’s score

Best overall transfer switch for essential circuits

  • Covers the circuits most households actually need during an outage — fridge, sump pump, furnace blower, some lights
  • Color-coded wiring and a widely recognized install pattern most electricians are already familiar with
  • Works with any portable generator in its amperage range, not tied to one generator brand

Watch out Still requires a licensed electrician to install inside your panel, and only covers 6 circuits

Check price on Amazon

Reliance Controls TF151W (Pro/Tran 2, 30-Amp 10-Circuit Transfer Switch)

Runner-up

9.3/10Editor’s score

Best for covering more circuits on a 30-amp generator

  • 10 circuits instead of 6, so more of a household's essentials fit on one switch
  • Pre-wired, color-coded breakers simplify the electrician's install
  • Compact design mounts next to most standard panels

Watch out Still capped by a 30-amp generator's total output, so more circuits means less power to split between them

Check price on Amazon

Reliance Controls 310CRK (Pro/Tran, Outdoor-Mounted 30-Amp Transfer Switch)

Best Value

9.0/10Editor’s score

Best for mounting outside without opening up the main panel

  • Pre-wired outdoor box mounts near the meter, which some electricians prefer over opening the main panel
  • Weatherproof enclosure rated for permanent outdoor installation
  • Includes the power inlet built in, so there's no separate inlet box to buy

Watch out Outdoor mounting location still has to make sense for your home's layout and meter placement

Check price on Amazon

Champion Power Equipment 50-Amp Transfer Switch Kit

Also great

8.7/10Editor’s score

Best for higher-output generators and larger circuit counts

  • 50-amp rating matches larger portable and dual-fuel generators that outgrow a 30-amp switch
  • Covers more circuits than a typical 30-amp switch, depending on the kit configuration
  • Kit includes the power inlet box and cord along with the switch

Watch out Only worth buying if your generator can actually supply 50 amps — match the switch to your generator's output, not the other way around

Check price on Amazon

Siemens Generator Interlock Kit (for compatible Siemens/Murray load centers)

Also great

8.4/10Editor’s score

Best lower-cost alternative when your panel supports it

  • Costs significantly less than a dedicated transfer switch
  • Uses your panel's existing breakers instead of adding a separate switch box
  • A straightforward add for an electrician already experienced with interlock installs

Watch out Only fits specific panel brands and models, and some jurisdictions restrict or disallow interlock kits versus a listed transfer switch — confirm both with an electrician before buying

Check price on Amazon

Reliance Controls PB30 (30-Amp Power Inlet Box)

Also great

8.3/10Editor’s score

Best power inlet box to pair with an indoor-mounted switch

  • Needed alongside an indoor transfer switch like the 31406CRK or TF151W, since those don't include an outdoor inlet
  • Weatherproof hinged cover protects the inlet between uses
  • Matches the 30-amp generator cord most portable generators already ship with

Watch out Not a complete solution on its own — it's the outdoor half of a setup that still needs an indoor transfer switch and a licensed electrician

Check price on Amazon

Frequently Asked Questions

Can I just plug my generator into an outlet to power my house?
No. Backfeeding through a wall outlet can energize your home's wiring (and the utility lines outside it), risking shock to you or utility workers, and it's illegal in most areas. A transfer switch or interlock kit, installed by a licensed electrician, is the safe way to do this.
What's the difference between a transfer switch and an interlock kit?
A transfer switch is a separate box with its own breakers for the circuits you choose, installed alongside your main panel. An interlock kit is a mechanical plate inside your existing panel that physically prevents your main breaker and a generator breaker from being on at the same time, letting you power the panel's existing circuits instead. Interlock kits are usually cheaper but only fit specific panel brands and models, and aren't accepted by every local code.
What amperage transfer switch do I need?
Match it to your generator's output and plug, not the other way around — most portable generators in the 3,000-7,500 watt range use a 30-amp (L14-30) connection, while larger dual-fuel and whole-home-oriented generators often step up to 50 amps (L14-50 or 14-50R). See our what size generator do I need guide if you haven't sized your generator yet.
Can I install a transfer switch myself?
This is electrical panel work, and most jurisdictions require a licensed electrician and a permit regardless of DIY skill level. Get it installed and inspected properly rather than treating it as a weekend project.
Does a transfer switch work with any portable generator?
As long as the generator's output plug and amperage match the switch and inlet box — most residential setups use a 30-amp L14-30 plug, with larger generators stepping up to a 50-amp L14-50 plug. Check your generator's cord and your intended switch's inlet before buying either one.

Keep reading

Category

Portable Generators Buying Advice

Guide

What Size Generator Do I Need?