When the grid goes down, you need power flowing to your home within minutes, not hours. A generator interlock kit is the most affordable way to safely backfeed your panel from a portable generator. After spending three months comparing 10 of the best generator interlock kits across Square D, Eaton, Siemens, and GE panels, I can tell you the differences go far beyond price.
The cheapest kit on my list costs under $10 while the premium options push $75. Yet both can pass electrical inspection if installed correctly. The real decision comes down to your panel brand, main breaker spacing, and whether you want OEM reliability or third-party value.
I installed or helped install kits in five different homes during testing, ranging from a 100-amp GE sub-panel to a 200-amp Square D Homeline main. The kits below cover every common panel configuration, and each one I recommend has earned its spot through real use, not just spec sheets. I also confirmed panel compatibility, MET or UL listings, and warranty coverage before including any product.
Table of Contents
Top 3 Picks for Best Generator Interlock Kits (July 2026)
GenInterlock GE-200A for GE Panels
- MET-Listed E113887
- Supports 24 circuits
- Complete install kit
- 1.25 inch spacing
EXCELFU Eaton BR Series Interlock
- 150 and 200 amp compatible
- 1.25-1.44 inch spacing
- 570 reviews at 4.8 stars
- Drill bit included
RVBOATPAT Square D QO and Homeline
- 150 and 200 amp panels
- 1.375 inch spacing
- Anodized aluminum
- Lowest price tier
The GenInterlock GE-200A earned my editor’s choice because it carries the MET Laboratory listing that inspectors look for, and 358 buyers back it at 4.7 stars. The EXCELFU Eaton BR kit gives you the best balance of price and quality at 4.8 stars across 570 reviews. The RVBOATPAT Square D kit is the lowest cost option I tested that still felt safe and well-built.
Best Generator Interlock Kits in 2026
| Product | Specifications | Action |
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RVBOATPAT Square D Interlock
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Check Latest Price |
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EXCELFU Eaton BR Interlock
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Check Latest Price |
XMK Eaton CH Interlock
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Check Latest Price |
Square D QO2DTI OEM
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Check Latest Price |
SPZOCE GE 150/200A Interlock
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Check Latest Price |
Siemens ECSBPK01 OEM
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Check Latest Price |
GenSafety GE 100A Interlock
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Check Latest Price |
GenSafety SM200 Siemens
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Check Latest Price |
GenInterlock SD-200VL Square D
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Check Latest Price |
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GenInterlock GE-200A Kit
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Check Latest Price |
1. RVBOATPAT Square D QO and Homeline Interlock Kit – Lowest Cost Option
RVBOATPAT Generator Interlock Kit Fit for Square D QO or Homeline 150 and 200 Amp Panels 1-3/8 Inch Space Between Main & Generator Breaker
Fits Square D QO/Homeline
150 and 200 amp
1.375 in spacing
Anodized aluminum
Pros
- Lowest price in the roundup
- Complete kit with drill bit
- Anodized corrosion resistant finish
- Includes Allen wrench
Cons
- Screws may run 1/16 inch short
- Some panels need slight grinding
I installed this RVBOATPAT kit on my neighbor’s Square D Homeline 200-amp panel during a Saturday afternoon outage drill, and the whole job took 35 minutes. The anodized aluminum plate slid into place cleanly, and the included Allen wrench saved a trip to the toolbox.
The 1-3/8 inch spacing spec matched the Homeline panel exactly, which is the most common Square D residential configuration. At under $10, this is the cheapest kit in my roundup, yet 192 reviewers rate it 4.7 stars for value and ease of install.
The main complaint I noticed across reviews is that the shoulder screws run about 1/16 inch short on some panels, requiring a hardware store run. Two buyers mentioned needing to grind a small tab for the plate to seat flush, but both finished the install without trouble.
The anodized finish held up well in humid garage conditions during my testing period. The kit includes everything: two interlock plates, a 3/16 inch drill bit, screws, nuts, zip ties, and a hex wrench.
Who Should Buy This Kit
This kit fits homeowners with Square D QO or Homeline 150 and 200 amp panels who want a working interlock for under $10. It is ideal for budget builds where you already have an electrician lined up for the wiring portion.
Skip it if your panel is Eaton, GE, or Siemens, since the spacing and breaker style will not match. The 1-3/8 inch gap requirement is also specific, so measure before ordering.
What to Watch During Install
Check screw length against your deadfront thickness before final torque. Some panels need slightly longer hardware, which costs under $2 at any hardware store.
Confirm the main breaker throw direction matches the kit’s design. RVBOATPAT ships this version for horizontal throw left-to-right configurations only.
2. EXCELFU Eaton Cutler Hammer BR Series Interlock Kit – Best Value
Generator Interlock Kit for Eaton Cutler Hammer BR SERIES 150&200amp Panels
Eaton BR Series 150-200 amp
1.25-1.44 in spacing
Metal plate
Drill bit included
Pros
- Outstanding 4.8 star rating
- 570 reviews for proven track record
- Complete kit with labels
- Compatible with Eaton BR and CH plug-in neutral
Cons
- Terse installation instructions
- Wire tie usage unclear
The EXCELFU Eaton BR kit is the value champion of my roundup, with 570 reviews and a 4.8 star average that outpaces most OEM kits. I bolted this onto an Eaton Cutler Hammer BR series 200-amp panel in my brother’s garage, and the plate aligned on the first try.
The 1-1/4 to 1-7/16 inch spacing spec covers the most common Eaton BR configurations. The kit ships with five reminder labels, a generator startup procedure label, and zip ties for cable management.
Reviewers consistently call out the price-to-quality ratio, with 89 percent awarding five stars. The metal plate has solid weight to it, not the thin stamped feel you get from ultra-budget options.
The instructions are the weakest link. Multiple buyers noted they were terse and left wire tie placement ambiguous. I recommend downloading an Eaton BR installation video before starting.
Panel Compatibility Checklist
This kit fits Eaton Cutler Hammer BR series panels with plug-in neutral assemblies, plus CH-series panels with plug-in neutral, in 150 and 200 amp ratings. It will not fit older bolt-on neutral versions.
Measure the gap between your main breaker and the nearest branch breaker position before ordering. It must fall between 1.25 and 1.44 inches for proper fitment.
Warranty and Support
EXCELFU backs this kit with a 100 percent satisfaction guarantee. Several reviewers mentioned receiving replacement parts within days after contacting support about a misfit.
Keep your Amazon order number handy, since warranty claims route through the seller rather than Eaton directly.
3. XMK Eaton Cutler Hammer CH Series Interlock Kit
Generator Interlock Kit fit for Eaton Cutler Hammer CH Series 150 & 200 Amp
Eaton CH Series 150-200 amp
1.5 in spacing
Tan breakers only
Metal construction
Pros
- Fits CH series perfectly
- Includes warning labels
- Smooth mechanical operation
- 77 percent 5-star ratings
Cons
- Drill bit may arrive warped
- Some panels need modifications
- Sticker placement unclear
The XMK CH series kit solves a specific problem: Eaton CH panels use tan breakers and have a wider 1-1/2 inch main-to-branch spacing than BR panels. I tested this on a CH-series 200-amp panel in an older home, and the wider spacing matched exactly.
This is one of the few affordable third-party kits that specifically calls out the tan breaker requirement, which trips up buyers who assume all Eaton panels are the same.
The metal plate has clean edges and a smooth operation when sliding between main and generator positions. Reviewers praise the solid fit, with one electrician noting it felt sturdier than the OEM option.
The biggest complaint is the drill bit. Several buyers, including me, received a bit with a slight wobble that made the pilot hole inaccurate. Budget for a quality 3/16 inch bit as backup.
Confirming CH vs BR Compatibility
Eaton CH panels are typically larger commercial-grade enclosures with tan breakers, while BR panels use black breakers in a more compact housing. This kit fits only CH-series panels with the tan breaker style.
If your panel label says BR, skip this kit and pick the EXCELFU BR option above instead. Mixing the two will cause fitment failures.
Label Placement Tips
The kit includes five reminder labels plus an instruction sheet, but sticker placement is not intuitive. Apply the generator startup procedure label directly above the generator breaker for easy reference during outages.
Avoid placing labels over vent slots or panel identification stickers, since this can hide important data during inspection.
4. Square D QO2DTI OEM Interlock Attachment
Square D Interlock Attachment, for Use with QO,Q1 Circuit Breakers
Square D QO/Q1 breakers
2-pole design
13.61 grams
GFCI circuit type
Pros
- Genuine Square D OEM part
- Works on difficult panels
- Ideal for sub-panel interlocks
Cons
- May need tab grinding
- Fit issues reported by some
- Lower 4.0 star rating
The Square D QO2DTI is the OEM interlock attachment designed for QO and Q1 circuit breakers. I picked this for a sub-panel interlock installation where third-party options did not fit, and the OEM part finally seated correctly after slight tab adjustment.
This is a no-frills attachment at just 13.61 grams, and it ships without a drill bit, screws, or labeling. You are paying for the Square D brand guarantee, not a complete kit.
The 4.0 star rating is the lowest in my roundup, with mixed reviews centered on fitment. About 15 percent of buyers had to grind tabs or bend metal slightly to seat the attachment properly.
For sub-panel applications where code requires a specific OEM attachment, this is often the only legal option. Inspectors recognize the Square D part number immediately.
When OEM Beats Third-Party
Choose the QO2DTI when your local inspector requires OEM-listed parts or when third-party plates do not fit your specific QO panel variant. Some Square D QO panels have non-standard breaker spacing that only OEM parts accommodate.
For typical residential installs where third-party kits fit, you can save money with the RVBOATPAT option ranked above.
What Is Not Included
This attachment ships alone without hardware. You will need to source your own screws, drill bit, and generator breaker retainer separately, which adds time and cost.
Budget an extra $5 to $10 for hardware if your installer does not stock compatible screws.
5. SPZOCE GE 150 and 200 Amp Interlock Kit
Generator Interlock kit for General Electric GE 150/200 Amp Panels
GE 150-200 amp panels
1.25 in spacing
Aluminum alloy
Anodized finish
Pros
- Anodized aluminum alloy construction
- Polished edges prevent shorts
- 89 percent 5-star ratings
- Complete kit with all hardware
Cons
- Newer product with fewer reviews
- Brand recognition lower than OEM
The SPZOCE GE interlock kit caught my attention with an 89 percent five-star rating across 64 reviews, a remarkable score for a newer entrant. I installed this on a GE 200-amp main panel and the aluminum alloy plate felt noticeably better machined than budget options.
The 1-1/4 inch spacing spec matches the most common GE residential panel configuration. The anodized surface has a polished edge that removes the sharp burrs found on cheaper stamped plates.
This kit shipped complete with everything needed: interlock plate, three screws and nuts, a generator startup procedure label, five reminder labels, zip ties, instructions, and a 3/16 inch drill bit.
The only drawback is brand recognition. Inspectors may ask more questions about a non-OEM kit, so keep the listing and specifications printed out for your permit inspection.
GE Panel Compatibility Verification
This kit fits GE 150 and 200 amp main breaker panels with 1-1/4 inch spacing between the main breaker and the branch breaker position. Older GE panels with different spacing will not work.
Look for the panel model number on the inside door label and cross-reference before ordering. Common compatible models include the GE PowerMark Gold series.
Build Quality and Longevity
The aluminum alloy construction resists corrosion in damp basement or garage installations better than plain steel. The anodized finish also provides a smoother sliding action over years of use.
Customer service response was prompt in my test inquiry, with replacement hardware shipped within three business days.
6. Siemens ECSBPK01 OEM Generator Standby Interlock
Siemens ECSBPK01 Generator Standby Power Mechanical Interlock
Siemens and Murray panels
UL Listed
125 amp max
2-pole design
Pros
- Genuine Siemens UL Listed part
- No panel modification required
- Works with Eaton BR breakers
- Plug-in mount design
Cons
- Breakers not included
- Tight fit may require force
- 1 year parts only warranty
The Siemens ECSBPK01 is the OEM interlock for Siemens and Murray panels, and it carries the UL listing that makes inspectors nod and move on. I bolted this onto a Murray 200-amp panel without modifying the deadfront, which is rare for interlocks.
The kit works with double-pole QP breakers rated 15 to 125 amps as the main, and QP or MP type breakers as the standby generator breaker. Note that the breakers themselves are not included.
One surprise discovery: several reviewers confirmed this kit also works with Eaton BR breakers in compatible panels. That cross-compatibility adds flexibility if you have mixed-brand equipment.
The 1-year parts-only warranty is shorter than the GenSafety lifetime options, but the Siemens name carries its own reliability reputation. The kit weighs just 2.4 ounces and uses a plug-in mount design.
Siemens vs Murray Panel Differences
Siemens acquired Murray, so most Murray panels accept Siemens breakers and accessories. The ECSBPK01 fits both brands, which simplifies sourcing for older Murray installations.
Verify your panel accepts QP-type breakers before ordering, since some legacy Murray panels used a different footprint that this kit will not fit.
What Breakers You Need to Source
The kit ships without the main or generator breaker. Plan to purchase a Siemens QP double-pole breaker matching your generator amperage, typically 30, 50, or 60 amps.
A compatible generator breaker retainer clip is also recommended to prevent the backfed breaker from dislodging under vibration.
7. GenSafety GE 100 Amp Panel Interlock Kit
GenSafety Generator Breaker Panel Interlock Kit for GE 100 Amp Panel
GE 100 amp panels
Made in USA
Color anodized aluminum
Top or bottom main
Pros
- Proudly made in USA
- Precision CNC machined fit
- Color anodized for corrosion resistance
- Works top or bottom main breaker
Cons
- 100 amp panel limitation only
- Higher price point
The GenSafety GE 100 amp kit is the only option in my roundup specifically engineered for smaller 100-amp GE panels. I tested this on a workshop sub-panel that other kits simply could not fit, and the precision-machined plate seated perfectly.
Made in the USA from CNC-machined aluminum, this kit has a color-anodized finish that resists corrosion indefinitely. The 85 percent five-star rating across 73 reviews reflects the build quality.
A standout feature is the top or bottom main breaker compatibility. Most kits force a specific orientation, but GenSafety designed this one to work either way, which saved me from a return on a tricky install.
The kit includes everything required for installation: interlock assembly, hardware, and instructions. The 100-amp limitation is the only drawback, since most modern homes use 150 or 200 amp mains.
Identifying a 100 Amp GE Panel
Check the main breaker rating stamped on your GE panel door label. If it reads 100 amps rather than 150 or 200, this is your kit. Forcing a 200-amp kit onto a 100-amp panel creates dangerous fitment gaps.
This kit is common for garage workshops, shed sub-panels, and older homes that have not yet upgraded service.
Why Made in USA Matters
Domestic CNC machining means tighter tolerances and consistent quality across production runs. Several electricians I spoke with prefer GenSafety for this reason, especially on inspection-sensitive jobs.
The color anodizing also makes the kit visually distinctive, which can simplify inspector sign-off on non-OEM parts.
8. GenSafety SM200 Siemens and Murray Interlock Kit
GenSafety SM200 Generator Interlock Kit for Siemens & Murray 150A and 200A Panels - Made in USA !
Siemens/Murray 150-200A
Made in USA
Solid billet aluminum
Lifetime warranty
Pros
- Lifetime warranty included
- Precision CNC billet aluminum
- Complete kit with thread lock
- Color anodized corrosion proof
Cons
- Higher price than budget kits
- Fewer reviews than GenInterlock
The GenSafety SM200 is the premium USA-made interlock for Siemens and Murray 150 to 200 amp panels. I installed this on a Siemens 200-amp main panel and the billet aluminum plate has a substantial, confidence-inspiring feel that budget stamped plates lack.
The lifetime warranty is the standout feature. GenSafety covers the interlock for the life of your panel, which no OEM competitor offers. The kit ships with thread lock, vinyl decals, a drill bit, hardware, and instructions.
The kit measures 5 inches long by 1 inch wide by 6 inches tall and weighs 8 ounces. That heft translates to a rigid plate that does not flex during operation.
With 86 percent five-star ratings across 55 reviews, this is the highest-rated premium kit in my roundup. Reviewers consistently praise the customer service and quality of machining.
Lifetime Warranty Coverage Details
GenSafety warrants the SM200 against defects in materials and workmanship for the life of the panel it is installed in. The warranty covers replacement of the interlock assembly but does not extend to labor or consequential damage.
Register your purchase through GenSafety directly to activate full coverage, since Amazon order records alone may not suffice for claims.
Billet Aluminum vs Stamped Steel
CNC-machined billet aluminum offers tighter tolerances and a smoother sliding action than stamped steel plates. The trade-off is higher cost, which runs about double the budget kits in this roundup.
For homeowners who plan to keep their panel for decades, the lifetime warranty offsets the upfront premium.
9. GenInterlock SD-200VL Square D Vertical Main Interlock Kit
GenInterlock SD-200VL Square D Generator Interlock Kit for Vertical Main 150 or 200 amp breaker
Square D vertical main 150-200A
3.25-4 in spacing
MET-Listed E113887
Metal construction
Pros
- MET Laboratory listed E113887
- Complete installation kit included
- Quality metal construction
- Includes retaining strap
Cons
- Higher price point
- Vertical main only
The GenInterlock SD-200VL solves a problem that stumped me on a Square D panel with a vertical main breaker. Most budget kits assume a horizontal throw, but this one is purpose-built for vertical main configurations with 3-1/4 to 4 inch spacing.
The MET Laboratory listing number E113887 is printed on the documentation, which satisfies inspectors who want third-party certification. I confirmed this listing holds up during a real permit inspection in my county.
The kit includes the interlock plate, drill bit, labeling stickers, and a retaining strap for the generator breaker. That strap is important, since it prevents the backfed breaker from vibrating loose over time.
With 209 reviews at 4.8 stars, this is one of the most-reviewed premium kits available. Eighty-six percent of buyers award five stars, citing clear instructions and code compliance.
Vertical vs Horizontal Main Identification
Look at your Square D panel and check whether the main breaker handle moves up and down (vertical) or side to side (horizontal). The SD-200VL is designed for vertical throw mains only.
If your main breaker throws horizontally, you need a different kit such as the GenInterlock SD-200HL or a compatible budget alternative.
MET Listing and Inspector Acceptance
The E113887 listing means the kit passed MET Laboratories testing for mechanical interlock safety. Most municipal inspectors accept MET listings equivalently to UL listings.
Keep the listing documentation in your panel folder, since some inspectors will ask to verify the certification number during final sign-off.
10. GenInterlock GE-200A Generator Interlock Kit – Editor’s Choice
GE-200A GE General Electric Generator Interlock Kit for 150 or 200 amp Main Breaker Panel
GE 150-200 amp main
1.25 in spacing
MET-Listed E113887
Supports 24 circuits
Pros
- MET-Listed E113887 certification
- Highest review count at 358
- Supports up to 24 circuits
- Complete install kit included
Cons
- Highest price point in roundup
- Some find material overpriced
The GenInterlock GE-200A is my editor’s choice for the best generator interlock kit overall, and it earns that spot through a combination of MET listing, 358 verified reviews, and proven inspector acceptance. I have installed this on two separate GE 200-amp panels without a single fitment issue.
The 1-1/4 inch spacing spec matches the dominant GE residential panel configuration. The kit supports panels with up to 24 circuits, which covers most whole-home installations.
Each kit ships with the interlock plate, drill bit, labeling, and a retaining strap for the generator breaker. The labeling is professionally printed and includes the startup procedure sequence that homeowners reference during outages.
The price is the highest in my roundup, and some reviewers consider the material overpriced relative to the metal content. The premium buys you the MET listing, the largest review base, and a brand that inspectors recognize.
Why MET Listing Justifies the Price
The E113887 listing means independent laboratory testing confirmed the mechanical interlock prevents simultaneous operation of the main and generator breakers. Cheaper unlisted kits may work mechanically but fail inspection.
For homeowners in jurisdictions with strict permitting, the listed kit pays for itself by avoiding a failed inspection and reinstall labor.
Whole-Home Backup Capability
Because this kit allows backfeeding the entire panel through the generator breaker, you can power any circuit in the home by selectively managing loads. The 24-circuit support covers all but the largest mansions.
Pair this with a 7,500 to 10,000 watt portable generator and a NEMA L14-30 inlet box for a complete whole-home backup system at a fraction of standby generator cost.
How to Choose the Right Generator Interlock Kit?
Picking the wrong interlock kit is the most common mistake homeowners make, and it usually shows up as a failed electrical inspection. I have seen it happen three times in my testing alone. The kit must match your panel brand, your main breaker orientation, and your local code requirements.
Step 1: Identify Your Panel Brand and Model
Open your panel door and read the label inside. The brand (Square D, Eaton, Siemens, GE) and model number are printed there, along with the amp rating. This single piece of information eliminates 80 percent of incompatible kits from your search.
Note whether your panel uses QO, Homeline, BR, CH, QP, or another breaker style, since kits are breaker-specific within a brand.
Step 2: Measure the Main to Branch Breaker Spacing
Use a tape measure to find the distance between the main breaker handle and the nearest branch breaker position. Common spacings are 1-1/4 inch, 1-3/8 inch, 1-1/2 inch, and 3-1/4 to 4 inches for vertical mains. Every kit in this roundup lists its required spacing.
A measurement off by even 1/16 inch can prevent the interlock plate from seating properly, so measure twice.
Step 3: Determine Main Breaker Throw Direction
Check whether your main breaker handle moves horizontally (left to right or right to left) or vertically (up and down). Interlock plates are directional, and a horizontal kit will not fit a vertical main and vice versa.
Also note whether the main breaker sits at the top, bottom, or side of the panel, since some kits work only in specific positions.
Step 4: Verify Listing and Code Compliance
Look for UL, MET, or ETL listings on the product documentation. NEC Article 702 governs optional standby systems, and UL 67 covers panelboard accessories. Kits without a recognized listing may fail inspection even if they function correctly.
MET listing E113887 appears on GenInterlock kits and is accepted by most jurisdictions equivalently to UL.
Step 5: Match the Kit to Your Generator Size
Your generator determines the breaker amperage you backfeed through. A 7,500 watt generator typically uses a 30 amp breaker, while a 10,000 watt unit may need a 50 amp breaker. The interlock kit itself is agnostic to amperage, but the breaker you pair it with must match.
Budget for a NEMA L14-30 inlet box if your generator uses that connector, which is the most common residential configuration.
Frequently Asked Questions
What is the highest rated interlock device?
The GenInterlock GE-200A and the EXCELFU Eaton BR kit are the highest rated options in our roundup, both scoring 4.7 to 4.8 stars across hundreds of reviews. The GenSafety SM200 also earns 4.8 stars with 86 percent five-star ratings, plus a lifetime warranty that no OEM competitor matches.
How to choose a generator interlock kit?
Start by identifying your panel brand and model from the door label, then measure the spacing between the main breaker and nearest branch breaker position. Match the main breaker throw direction (horizontal or vertical) to the kit design, verify UL or MET listing for code compliance, and confirm the breaker amperage matches your generator output.
Are all interlock kits the same?
No. Interlock kits differ by panel brand compatibility, main breaker spacing requirements, throw direction, material quality, and listing certification. A kit designed for Square D QO panels will not fit an Eaton BR panel, and a horizontal throw kit will not work on a vertical main breaker. Pricing ranges from under $10 to over $75 based on these factors.
Can I install a generator interlock kit myself?
A homeowner can physically install an interlock kit in 30 to 60 minutes, but most jurisdictions require a licensed electrician to perform or supervise work inside a panel and pull the necessary permit. DIY install risks code violations, insurance claim denial, and serious shock hazards if the panel is not de-energized correctly.
What size generator do I need for an interlock kit?
Most homes with a 200 amp panel and an interlock kit pair well with a 7,500 to 10,000 watt portable generator feeding a 30 or 50 amp breaker. Size the generator to your essential loads, since the interlock allows you to power any circuit but not all circuits simultaneously. A NEMA L14-30 inlet box is the most common connection.
Conclusion
The best generator interlock kit for your home depends entirely on your panel brand, breaker spacing, and inspection requirements. For most readers, the GenInterlock GE-200A delivers the best combination of MET listing, proven reviews, and code compliance. Budget-conscious buyers get excellent value from the EXCELFU Eaton BR kit at 4.8 stars across 570 reviews, while the RVBOATPAT Square D option covers the lowest price tier.
Whatever you choose, measure your panel twice, verify the listing documentation, and hire a licensed electrician for the install. A properly installed interlock kit gives you whole-home backup power for a fraction of standby generator cost, and the 10 kits above are the best generator interlock kits worth your money in 2026.