Powering your house from a portable generator through an extension cord is slow and limited. Plugging that generator straight into your electrical panel is fast, and it is also the most dangerous thing a homeowner can do without the right hardware. A generator interlock kit is the small mechanical device that makes that connection safe, and choosing one comes down to a single question: which panel is on your wall.
We compared the best generator interlock kits for home panels across every major panel family, reading the review data behind more than 3600 owner ratings and mapping each kit back to the brand, series and amperage it was actually built for. The findings were consistent: the most expensive kit is not automatically the best one, and a plate is either a perfect fit or a drilled mistake.
Backfeeding is what an interlock prevents. If the main breaker is on and you energize the panel from a generator, line voltage flows back toward the utility, where a lineworker on a downed line can be electrocuted. It is also illegal under the National Electrical Code. A mechanical interlock makes the mistake physically impossible, with no sensors or electronics that could fail in a blackout.
Table of Contents
Top 3 Generator Interlock Kits for Home Panels (October 2026)
Natupal SD200A for Square…
- Fits Square D QO or Homeline 150/200A panels
- 1-3/8 inch main-to-branch spacing
- Drill bit
- shoulder screws and labels included
- 1768 owner ratings averaging 4.7 stars
EXCELFU GK-PN200 for Eaton…
- Fits BR and CH series 150/200A panels
- 1-1/4 to 1-7/16 inch spacing
- 4.8 star average with 89 percent five star ratings
- Complete hardware and drill bit in the box
GenSafety BR-200 Machined…
- CNC machined anodized aluminum plate
- Works on top-main and bottom-main BR and CH panels
- Built for panels without a recessed main breaker
- Made in the USA with photo instructions
Identify Your Electrical Panel Before You Buy Anything
Most interlock kit returns come down to one mistake: guessing at the panel. Four checks identify your panel and the right kit in about ten minutes, and every one is free.
Start with the panel door. Every residential load center carries a label listing the manufacturer and series, such as Square D Homeline, Square D QO, Eaton BR, Siemens, Murray or GE. Some older or field-modified panels have no readable label at all. If that is your situation, photograph the panel with the cover off, note the branch breaker brands, and send both to the seller before ordering, which is the workflow vendors in this category are built around.
Next read the main breaker amperage from the handle label, typically 100A, 125A, 150A, 200A or 225A, and note the throw direction. A main with the ON position at the top is vertical throw; one that throws in from the side is horizontal. These need different plates, and buying the wrong one is the most common purchase mistake on retail listings.
Finally, measure the gap center-to-center between the main breaker and the first branch breaker position, which is where your generator breaker will go. Measure the breaker bodies rather than the bus bars and record the exact fraction. Common values run 3/4 to 7/8 inch, 1 inch, 1-1/4 inch, 1-3/8 inch and 1-7/16 inch, and a plate cannot be un-drilled.
All 10 Generator Interlock Kits Compared in 2026
| Product | Specs | Action |
|---|---|---|
| Natupal SD200A Square D QO and Homeline Kit |
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Check Latest Price |
| EXCELFU GK-PN200 Eaton Cutler Hammer Kit |
|
Check Latest Price |
 Square D HOMCGK2C Homeline Cover Kit |
|
Check Latest Price |
 XMK GK-PN400 Siemens and Murray Kit |
|
Check Latest Price |
 EXCELFU GK-PN300 General Electric Kit |
|
Check Latest Price |
| GenSafety BR-200 Premium Aluminum Kit |
|
Check Latest Price |
 Gen Interlock SD-200SA Meter Main Kit |
|
Check Latest Price |
 Natupal ITE-200A Multi-Brand Kit |
|
Check Latest Price |
 XMK GK-007 Square D 100 and 125 Amp Kit |
|
Check Latest Price |
 HUBRV Stainless Steel Eaton BR Kit |
|
Check Latest Price |
1. Natupal SD200A Interlock Kit: Best Overall for Square D Panels
Natupal Generator Interlock Kit Compatible with Square D QO or Homeline 150 or 200 amp panels. 1 3/8 inches Spacing between main and generator breaker, Professional and Interlock Kit (SD200A)
Square D QO or Homeline 150/200A
1-3/8 inch spacing
Drill bit and labels included
Pros
- Matches Square D QO and Homeline 150/200A panels at 1-3/8 inch spacing
- 1768 owner ratings averaging 4.7 stars
- Complete hardware with shoulder screws
- hex nuts
- drill bit and start-up label
- Reviewers report about a ten minute mount for mechanically skilled users
Cons
- Does not fit 100 amp Square D panels
- Requires moving branch breakers down to create spacing
- Instructions are brief for first-time installers
Square D panels are among the most common load centers in American homes, which is why the Natupal SD200A carries more owner ratings than any other kit here. It is specified for Square D QO or Homeline panels at 150 or 200 amps with 1-3/8 inch spacing.
What separates it from the pack is the box contents: the plate, three shoulder screws, three hex nuts, a matched 3/16 drill bit, a generator start-up procedure label, five reminder labels, two zip ties and an instruction bulletin. Shipping the correct bit removes the most common install mistake, because the hole has to be exactly the right diameter and position.
The plate measures 3 by 0.6 by 5.8 inches and weighs about a quarter pound, so it sits flat against the panel side without crowding the bus bars. Material is steel with a silver and black finish, rated 200A at 220 volts, manufacturer part number SD200A-B.
Owners report that the plate moves smoothly and blocks the main handle cleanly, and that a mechanically skilled user can finish mounting in roughly ten minutes. The most common complaint in reviews is not build quality but fit.
Best for Square D owners who want the most proven plate
If your panel is Square D QO or Homeline at 150 or 200 amps and you measure 1-3/8 inch to the first branch position, this is a well-proven purchase. The volume of real-world installs behind it is the largest here, which matters because a wrong choice means a drilled panel.
It also suits a first-time installer, because the matched drill bit and labeled hardware remove two sources of error. Homeowners use this arrangement to feed a well pump, a freezer and lighting without running an extension cord across a wet garage floor.
Not the right fit if your panel is smaller or spaced differently
Owners of 100 amp Square D panels report that it does not fit, and the spacing requirement is fixed rather than adjustable. If your main is 100A or 125A, or the measurement comes back wider than 1-3/8 inch, look at a kit built for that geometry.
Expect to move branch breakers down a slot or two to open the gap, which means you need slack in those branch wires. Read the brief instructions alongside a general walkthrough rather than treating them as the whole guide.
2. EXCELFU GK-PN200 Interlock Kit: Best Rated for Eaton and Cutler Hammer
Generator Interlock Kit for Eaton Cutler Hammer BR SERIES 150&200amp Panels
Eaton BR and CH series 150/200A
1-1/4 to 1-7/16 inch spacing
Metal plate with full hardware
Pros
- 4.8 star average across 574 reviews with 89 percent five-star ratings
- Covers BR and CH series with plug-in neutral at 150 and 200 amps
- Matching drill bit
- hardware
- warning labels and instructions
- Reviewers report smooth plate movement that reliably blocks the main handle
Cons
- Only fits panels measuring 1-1/4 to 1-7/16 inch spacing
- An existing branch breaker may need to move down
- Instructions are brief
- so measurement is the key step
Eaton and Cutler Hammer panels are the other big residential family, and the EXCELFU GK-PN200 is the best-documented 4.8-star kit we found for them. It fits BR and CH series with plug-in neutral at 150 and 200 amps, using a single handle main that throws horizontally.
The spec that matters is the range: the plate works between 1-1/4 inch and 1-7/16 inch of main-to-branch spacing, a wider window than most competing kits allow. That tolerance is why it fits panels a fixed-spacing kit would miss. Part number GK-PN200, 200A, 60 hertz, single phase.
At 4.8 stars across 574 ratings with 89 percent five-star scores, the rating profile is strong. Reviewers credit the fit on real BR and CH panels and the way the plate slides to block the handle without binding, which is the behavior that actually prevents a backfeed.
The box carries the plate, three shoulder screws, three hex nuts, the drill bit, a start-up procedure label, five reminder labels, two zip ties and instructions. That is a complete install, not a plate in a plastic bag.
Best for Eaton BR and CH panels with spacing to spare
Choose this when your load center is a Cutler Hammer or Eaton BR or CH at 150 or 200 amps and your measurement falls anywhere in that 1-1/4 to 1-7/16 inch band. The range is the reason it succeeds where tighter-spec kits fail.
It is also a strong pick if you want depth of review evidence behind a high rating. 574 ratings at 4.8 stars is a firmer signal than a small sample, and buyers describe the same smooth throw rather than a binding or intermittent block.
Watch the spacing and expect to shift a breaker
The window has edges. Panels with gaps wider than 1-7/16 inch will not line up, and some boxes require moving an existing branch breaker down a position to open the gap.
The instructions assume you already know your panel, so measurement is where care pays off. Measure twice before drilling, and confirm the main is a single handle that throws side to side rather than a vertically mounted double handle.
3. Square D HOMCGK2C Homeline Cover Kit: Best Factory Hardware for Homeline
Square D – HOMCGK2C Homeline Cover Generator and QOM2 Frame Size Main Breaker Interlock Kit
OEM Schneider Electric HOMCGK2C
QOM1 or QOM2 frame main breaker
Indoor Homeline 150A to 225A
Pros
- Factory Square D by Schneider Electric part
- Handles Homeline load centers up to 225A main breaker
- Complete hardware with drilling template
- retaining bracket and shoulder screws
- No separate generator panel needed
Cons
- Only fits Homeline load centers with QOM1 or QOM2 frame mains
- Marked for indoor use only
- Costs noticeably more than aftermarket plates
- Drilling template marks only one hole
When your panel is a Square D Homeline and you want hardware from the company that stamped the box, the HOMCGK2C is the factory answer. This is a genuine Square D by Schneider Electric part rather than a third-party plate sized to fit the opening.
It interlocks a QOM1 or QOM2 frame main with a two-pole breaker back fed from a generator, rated for indoor Homeline load centers from 150A to 225A. That 225A ceiling is higher than the aftermarket kits in this roundup, which top out at 200A.
Owner reactions are consistent: the finish matches the panel hardware, the hardware set is complete, and the piece feels like it belongs inside that enclosure. At 4.6 stars across 292 ratings with 82 percent five-star scores, it is well liked and not inflated.
In the box you get an interlock bracket, a retaining bracket, a one-hole drilling template, three hex nuts, three 10-32 shoulder screws and an interior mounting screw. The retaining bracket is what keeps your generator breaker from walking out of position.
Best for Homeline owners who want OEM hardware or a 225A panel
This is the pick if your Homeline has a 200A or 225A main, if your inspector prefers factory hardware, or if you want certainty the component was engineered against that panel series. It also covers a 225A service rating that the aftermarket plates here cannot.
Buyers also like that the choice of which circuits the generator feeds happens inside the existing panel, with no second subpanel to mount and no extra feeder to run.
Narrow compatibility and a one-hole template
Compatibility is tight. It covers Homeline load centers with QOM1 or QOM2 frame mains only, so it will not serve a QO panel, a different Square D series or any other brand, and it is marked for indoor enclosures.
Reviewers note the drilling template marks a single hole, so you still need to lay out the generator breaker position on your actual panel. It also costs noticeably more than a stamped plate doing the same job, which is the trade for OEM provenance.
4. XMK GK-PN400 Interlock Kit: Best for Siemens and Murray Panels
Generator Interlock Kit Compatible with Siemens Murray 150 or 200 Amp Panel
Siemens and Murray 150/200A panels
7/8 to 1-1/4 inch spacing
Drill bit and hardware included
Pros
- Purpose-built for Siemens and Murray 150/200A panels
- Matching drill bit and full hardware in the box
- 4.7 stars across 294 ratings with 85 percent five-star scores
- Plate moves smoothly and clearly blocks the main handle
Cons
- Requires 7/8 to 1-1/4 inch spacing exactly
- Wider gaps will not line up
- Some panels need a branch breaker moved down an extra slot
Siemens and Murray panels are common in homes built before the 1990s, and the XMK GK-PN400 is purpose-built for them at 150 and 200 amps. Model GK-PN400, 200A, 60 hertz, single residential-use kit.
The defining spec is the tight spacing window of 7/8 to 1-1/4 inch. Older Siemens and Murray load centers use narrower bus spacing than modern Square D or Eaton panels, which is why a generic modern kit frequently will not fit them.
Buyers confirm the fit on real Siemens and Murray load centers and report that the plate slides smoothly and blocks the main handle decisively. At 4.7 stars across 294 ratings with 85 percent five-star scores, satisfaction is in line with the strongest kits here.
The kit includes the plate, three shoulder screws, three hex nuts, a matching drill bit, five reminder labels, two zip ties and instructions. The plate measures 6.5 by 5.5 by 0.4 inches, described as aluminum or steel at about 0.15 kg.
Best for older homes with legacy Siemens or Murray load centers
If your panel is Siemens or Murray at 150 or 200 amps and the measurement lands between 7/8 and 1-1/4 inch, this is the correct kit. It stays honest about the narrow geometry instead of claiming universal fit.
For pre-1990 housing stock, having a match for these brands is the difference between a clean install and a search that ends in a custom fabricated plate. Matching the legacy brand is the hardest part of this decision, which is why the photo-plus-measurement workflow exists.
Strict spacing, and plan for a breaker move
Outside that 7/8 to 1-1/4 inch window the plate will not line up, and a mismatch is not recoverable after drilling. Verify the panel model and the measurement before ordering, not at install time.
Some panels also require moving a branch breaker down an extra slot. A stuck or jammed breaker is more common in older panels than modern ones, and that is a job for someone comfortable working inside a de-energized enclosure.
5. EXCELFU GK-PN300 Interlock Kit: Best for GE Load Centers
Generator Interlock Kit Compatible with General Electric GE 150 or 200 Amp
General Electric 150 and 200 amp panels
1-1/4 inch spacing
Single phase up to 200A
Pros
- Covers GE panels common in older homes
- 4.6 stars across 256 ratings with 82 percent five-star scores
- Includes plate
- shoulder screws
- hex nuts
- drill bit
- labels and instructions
- Clean install reported on GE 150 and 200 amp load centers
Cons
- Requires exactly 1-1/4 inch spacing
- Brand coverage is limited to GE alone
- No other panel manufacturer is supported
GE panels have largely disappeared from new residential construction but are common in older housing, which makes a GE-specific kit worth checking first. The EXCELFU GK-PN300 fits General Electric 150 and 200 amp panels.
The spec is narrow and worth stating plainly: 1-1/4 inch of spacing between the main and the branch breakers, single phase, up to 200A. That is a single fixed number rather than a range, so the measurement must land on it exactly. Model GK-PN300, metal, silver grey and black finish.
Owners of GE load centers report a clean install and confirm the package includes everything needed: the plate, three shoulder screws, three hex nuts, the drill bit, five reminder labels, two zip ties and instructions. Rated for three circuits, residential use.
Ratings sit at 4.6 stars across 256 reviews with 82 percent five-star scores. The praise is mostly about fit and completeness, and the criticism is mostly about the fixed spacing figure.
Best for GE panel owners who can hit the spacing figure
If your home has a GE load center at 150 or 200 amps and the main-to-branch measurement reads 1-1/4 inch, this is a direct match. Buyers with that combination report the install going as described.
Having a kit that names your brand removes the guesswork that makes people buy the wrong plate twice. The included drill bit and hardware also keep the install to a single parts purchase.
Brand coverage is limited to GE alone
Unlike the multi-brand kits later in this roundup, this one supports no other manufacturer. If your GE-labeled panel was field-modified with mixed breakers, or the measurement is off by an eighth of an inch, it will not cover you.
The fixed 1-1/4 inch requirement is also narrower than the ranges offered by comparable BR and CH kits. Measure carefully and be ready to move a branch breaker if the gap is not exactly right.
6. GenSafety BR-200 Interlock Kit: Best Premium Machined Aluminum Build
GenSafety BR-200 Generator Interlock Kit for Cutler Hammer BR and CH Series 150AMP and 200 AMP Panels – Made in USA !
Eaton and Cutler Hammer BR and CH
CNC machined anodized aluminum
Built for non-recessed mains
Pros
- CNC machined anodized aluminum plate feels far sturdier than stamped generic kits
- Works on both top-main and bottom-main CH panels
- Instructions include photos of different box styles
- Includes a drill bit and thread locker
- Made in the USA with responsive small-business service
Cons
- Costs several times the budget stamped steel options
- Will not fit panels with a recessed main breaker
- A small leg may need trimming on some boxes
Where most interlock plates are stamped from sheet metal, the GenSafety BR-200 is CNC machined from color-anodized aluminum, and owners describe the difference in hand-feel and in how the plate seats against the breaker handles.
It works on Eaton and Cutler Hammer 150 and 200 amp panels, including top-mounted and bottom-mounted mains. The critical caveat is in the product data itself: it is designed for panels without a recessed main breaker, so a stepped or recessed main area needs a different kit.
At 4.8 stars across 261 ratings with 87 percent five-star scores, this shares the highest average in the group. Buyers single out the photo-based instructions covering several enclosure styles, and describe finishing the mount quickly once compatibility is confirmed.
The package includes a drill bit and thread locker, which stops the shoulder screws loosening as the plate is cycled over years. Blue anodized aluminum, 200A, indoor use, 8 ounces, made in the USA.
Best for owners who want a plate that outlasts the panel
Choose this if you plan to run a portable or standby generator for years and would rather buy metal once. The machined plate resists the flexing and handle wear that eventually shows up in thin stamped kits.
It also covers a CH panel with the main breaker mounted at the bottom, since it works in both positions. The photo instructions show several enclosure styles, which helps on an unusual box layout.
Price and the recessed main breaker rule
This kit costs several times a budget stamped steel plate, and the premium buys material and finish rather than extra function. For a one-time storm-season install, the budget plates do the same mechanical job.
The recessed main breaker limitation matters more. Check whether your panel has a flat or raised area around the main before ordering, because a recessed main needs a different design. A few owners also note a small leg that may need trimming on certain enclosures.
7. Gen Interlock SD-200SA: Best MET Listed Kit for Meter Main Panels
SD-200SA Square D Generator Interlock Kit for Homeline Meter Main 150 or 200 amp Breaker
Square D 150/200A meter main panels
MET lab listed E113887
Retaining strap and labeling
Pros
- MET lab listed under E113887
- which matters for inspector sign-off
- Retaining strap holds the generator breaker plus visible procedure labeling
- One owner used it on an older 150 amp load center with no branded kit available
- Long-standing listing with 203 reviews
Cons
- Several reviewers call it overpriced for a stamped plate with screws and labels
- Only for 150/200A Square D meter main panels
- Some panels have spacing so tight a branch breaker must move
Certification is the dividing line between kits that pass inspection without argument and kits that might not. The Gen Interlock SD-200SA carries a MET Laboratories listing under E113887, the most valued trust signal in homeowner discussions about this hardware. It fits Square D 150 or 200 amp meter main panels.
It is a panel mount design rated 200A for 240 volts AC. The kit includes the interlock, a drill bit, warning labeling and a retaining strap for the generator breaker, and the seller instructs buyers to verify panel type against the product photographs.
Reviewers confirm a close fit and a plate that moves smoothly, and several have fitted it in older 150 amp load centers where no branded kit was offered. At 4.6 stars across 203 reviews, the feedback is solidly positive on function.
The most repeated complaint is price: several reviewers describe it as expensive for a stamped plate, screws and labels, which is fair against an unlisted generic kit. The counterpoint is the MET listing, which is what lets it sign off with an inspector when a homeowner sells the house.
Best when the inspector or insurer is part of the decision
Pick this if your local authority having jurisdiction requires a listed device, if you plan to sell the house soon, or if you would rather not argue about certification. MET listing is a recognized third-party lab listing that inspectors accept.
The retaining strap and visible labeling matter more than they look. The strap keeps the generator breaker from drifting out of position, and the labels remind everyone in the house which breaker gets switched during an outage.
Limited to meter main panels, and priced like a premium
Compatibility is limited to Square D 150 and 200 amp meter main panels. It will not serve a 100 amp box, a different Square D series or any other manufacturer, so verify the panel type first.
On tight panels you may need to move a branch breaker to open the required gap. Several reviewers call the price hard to justify next to a generic plate, so the value here is the certification and retention hardware rather than the metal.
8. Natupal ITE-200A Interlock Kit: Best Multi-Brand Kit for Legacy Panels
Natupal Generator Interlock Kit Compatible with ITE, Gould, Murray, Siemens, and Thomas and Betts, 150 or 200 amp panels, 1 1/4 Inch Spacing between main and generator breaker
ITE, Gould, Murray, Siemens, Thomas and Betts
1-1/4 inch spacing
Reversible orientation
Pros
- Five legacy panel manufacturers covered in one kit
- Reversible so the generator breaker can sit on either side of the main
- Low cost while holding a 4.6 star average
- Includes drill bit
- shoulder screws
- hex nuts
- labels
- zip ties and instructions
Cons
- Fixed 1-1/4 inch spacing will not suit wider measured panels
- May require moving two breakers on one side down two slots
- Value proposition is thin for two pieces of metal and labels
The hardest part of buying an interlock kit is not the hardware, it is the identification. The Natupal ITE-200A covers five legacy brands in one kit: ITE, Gould, Murray, Siemens and Thomas and Betts, at 150 and 200 amps.
It requires 1-1/4 inch spacing and the plate is reversible, so it works with the generator breaker on either side of the main. Model ITE-200A, 3 by 0.6 by 5.8 inches, two-year warranty on the listing, residential use.
Buyers who got the fit right report that the kit satisfies the code requirement for whole-house backfeed without a separate transfer switch, and several confirm correct fit on Siemens and Murray 150 and 200 amp panels. The box includes the plate, screws, hex nuts, labels, zip ties, instructions and a 3/16 drill bit.
At 4.6 stars across 197 ratings, the profile is solid but the sample is thinner than the Square D option. The most instructive review describes a 200A Siemens outdoor panel measuring 2-1/4 inch, which left the plate about three-quarters of an inch short. Measure before ordering.
Best when your panel brand is uncertain or old
This is the kit if your panel has no readable brand name, if it is an older ITE, Gould or Thomas and Betts box, or if you are buying for a relative whose panel nobody has opened. Covering five manufacturers in one purchase is a practical hedge.
The reversible orientation helps in crowded panels where the only realistic spot for the generator breaker is the side you would not have chosen, and it works in top-main and bottom-main configurations of the supported brands.
Fixed spacing is the whole risk
The 1-1/4 inch requirement has no adjustment. Panels measuring wider, including some outdoor 200A Siemens enclosures, will not accept the plate. You may also need to move two breakers down a couple of slots, which needs spare wire length in those circuits.
Some reviewers feel the value is thin given the contents, so buy it for its brand coverage rather than for how much metal is in the box.
9. XMK GK-007 Interlock Kit: Best for 100 and 125 Amp Square D Panels
Generator Interlock Kit for Square D QO or Homeline 100 or 125 Amp Panels
Square D QO or Homeline 100/125A
3/4 to 7/8 inch spacing
Indoor or outdoor panels
Pros
- Fills a real gap for 100 and 125 amp Square D panels
- Works on both indoor and outdoor QO and Homeline boxes
- Includes drill bit
- hardware
- start-up and reminder labels
- Low cost with a 4.5 star average
Cons
- Square D QO or Homeline 100/125A panels only
- Smaller review sample than the rest of the group
- Requires 3/4 to 7/8 inch spacing
Smaller Square D panels get overlooked, and most of the 150/200 amp kits in this roundup will not serve them. The XMK GK-007 is built specifically for Square D QO or Homeline panels at 100 and 125 amps, indoor or outdoor.
The spacing here is among the tightest of any kit we tested: 3/4 to 7/8 inch between the main and branch breakers, with a single handle main that throws horizontally. Model GK-007, 100A, standard breaker type, panel mount.
With 102 ratings and a 4.5 star average, the evidence base here is thinner than most. Even so, buyers with the right panel report that it does what it promises, and the box includes the plate, three shoulder screws, three hex nuts, a matching drill bit, start-up and reminder labels, zip ties and instructions.
Its one-star share of 5 percent is among the smallest here, and the 4.5 average reflects the smaller sample rather than a build problem.
Best for smaller Square D service panels
A 100 or 125 amp Square D panel is common in older homes, outbuildings and panels that have been downsized. If that is your situation, this is the correct kit and the larger-spacing alternatives here are not, which makes the choice easy.
It is also rated for outdoor enclosures, so a weather-exposed Square D box is covered. The included drill bit and hardware keep the install to a single parts purchase.
Square D only, and with the thinnest margin for error
Compatibility is Square D QO or Homeline at 100 and 125 amps and nothing else. It will not serve a 150 or 200 amp panel, and it will not serve any other manufacturer.
With a 3/4 to 7/8 inch window, measurement error has the least room to absorb. Measure before ordering, and confirm the main is a single handle that throws side to side. A wrong measurement means a drilled panel and a replacement plate.
10. HUBRV Stainless Steel Interlock Kit: Best Budget Build for Eaton BR
Generator Interlock Kit Compatible with Eaton Cutler Hammer BR Series 150 and 200 Amp Panels, Generator Horizontal Electrical Interlock Kit, 1 7/16-1 1/4 Inches Spacing Between Main and GEN Breaker
Eaton Cutler Hammer BR 150/200A
1-7/16 to 1-1/4 inch spacing
Stainless steel construction
Pros
- Low cost with a 4.8 star average
- Rating distribution shows no one or two star scores
- Stainless steel compares favorably to costlier OEM aluminum
- Fit confirmed on Eaton 200 amp panels at 1-1/4 inch
- States NEC 230.85 and 702.7 backfeed compliance
Cons
- Review base of 75 ratings
- Orientation-sensitive install
- one buyer initially thought it would not fit
- Eaton BR series 150 and 200 amp panels only
The HUBRV kit is the value pick of this group, and an unusual one: it holds a 4.8 star average across 75 ratings with no one or two star scores in the distribution. It fits Eaton and Cutler Hammer BR series panels at 150 and 200 amps.
Construction is stainless steel rather than the anodized aluminum used by premium kits, and reviewers compare the finish favorably to more expensive factory options. One buyer reported that a manufacturer version of the same function cost roughly six times as much. Part number H-GIK-ETN200, single phase, twelve circuits.
The listing states a spacing requirement of 1-7/16 to 1-1/4 inch and describes the device as supporting NEC 230.85 and NEC 702.7 backfeed requirements. Buyers confirm the fit on real Eaton 200 amp panels measuring 1-1/4 inch.
The package includes one matching drill bit, two fixing straps and installation and use instructions. Contents are leaner than the other kits here, which include hex nuts and reminder labels.
Best for Eaton BR owners who want stainless at low cost
If your panel is Eaton or Cutler Hammer BR at 150 or 200 amps and the measurement falls between 1-1/4 and 1-7/16 inch, this is a strong fit. Stainless resists corrosion in a damp garage or basement enclosure better than painted stamped steel, and no one or two star ratings appear in the distribution.
The explicit NEC 230.85 and 702.7 language also gives an inspector something concrete to see, which helps when explaining a non-factory device.
Orientation catches people out, and the review base is thin
One buyer initially concluded the plate would not fit before realizing it mounts in the opposite orientation. Check both positions against your panel before drilling rather than assuming a mismatch.
With 75 ratings, the long-term track record is limited. It also supports Eaton BR series panels only, and the fixing straps and drill bit are a leaner contents list than the alternatives here.
How to Choose a Generator Interlock Kit?
A generator interlock kit is a mechanical plate that mounts inside your load center and physically prevents the main breaker and the generator breaker from both being ON at the same time. Choosing one means matching a metal part to the exact geometry of your panel, and no kit is genuinely universal.
Start with six criteria, in this order. First, panel brand and series: match the manufacturer and series on the panel door label exactly, including Square D QO versus Square D Homeline, BR versus CH, and Siemens versus Murray. Second, the main breaker amperage, which determines whether a 100/125A, 150/200A or 225A kit applies.
Third, the main breaker throw, since a vertically thrown main and a horizontally thrown main need different plate geometry. Fourth, the center-to-center spacing between the main and the first branch position, measured in fractions and compared against the kit specification rather than assumed.
Fifth, certification: a UL listed or MET listed device has been evaluated by a third-party lab, while an unlisted plate may work and still create problems with an inspector, an insurance renewal or a home sale. Sixth, kit contents, since a matched drill bit, shoulder screws, hex nuts, a retaining strap and a start-up procedure label are what turn a plate into an installable kit.
If your panel brand has no listed kit, custom fabricators building MET listed interlock plates for odd or older panels are the fallback. Send them a panel photo and your spacing measurement and they will make a plate to fit, at higher cost than an off-the-shelf kit.
UL Listed vs MET Listed vs Uncertified Kits
This distinction is where most homeowner arguments happen, and the honest answer is uncomfortable: many unlisted kits work exactly as intended. The debate is not about function, it is about listing, liability and what happens when an insurance company or a home inspector asks questions.
UL listed means Underwriters Laboratories evaluated the device against a safety standard. A factory part from Square D or Schneider Electric arrives with that status, which is why the HOMCGK2C carries more cost than a generic plate doing the same job.
MET listed means MET Laboratories, a recognized third-party lab, evaluated the product under a listing number; the Gen Interlock SD-200SA in this roundup is listed as E113887. Most inspectors accept a MET listed device, and it is the strongest signal available when a kit is not an OEM part.
Uncertified covers everything else, including most stamped plates sold on marketplaces. Buyers in r/Generator and on powerequipmentforum.com report that unlisted kits are well designed and work fine, and the practical argument against them is rarely that they fail. It is that an unlisted device can complicate an insurance claim, fail an inspection and make a buyer’s home inspector flag the modification. If you go unlisted, have your electrician install it and sign off on the work.
Generator Sizing and Breaker Size
Your interlock kit and your generator have to agree on the breaker size, and this is where first-time buyers go wrong. The rule of thumb in this category is a 30A double-pole breaker for a mid-size portable generator and a 50A double-pole breaker for a full-output unit.
A 30A branch circuit at 120/240V supports roughly 7500 running watts, or about 3000 to 3750 usable watts after the 80 percent continuous load limit. That covers a refrigerator, several lamps, a television and a small pump, but not a well pump plus a freezer plus a furnace blower at once.
A 50A branch circuit supports roughly 9500 running watts, about 7600 usable watts continuous, which is why 10,000 watt generators pair with a 50A breaker. The generator nameplate sets the output and the breaker has to match it and the wire feeding it.
The generator breaker must be a two-pole device in a listed enclosure, sized by NEC 210.12 for the conductor and by the generator manufacturer for the output. Never oversize the breaker for more headroom, because the interlock plate was drilled for one specific two-pole footprint.
Interlock Kit vs Manual Transfer Switch vs Automatic Transfer Switch
An interlock kit is the least automatic option, and for many homes it is the right one. A manual transfer switch is a separate enclosure with transfer handles that swaps power sources for a defined list of circuits. An automatic transfer switch detects an outage, starts the standby generator and transfers power without anyone touching a handle.
The interlock wins on cost, simplicity and the ability to power the whole house by choosing circuits at the panel. It loses on convenience, because a human must flip the main off, flip the generator breaker on and start the generator in sequence every time.
The manual transfer switch wins on clean separation of circuits and repeatability: the same essentials get power every time without judgment calls. It costs more, needs its own enclosure and feeder, and limits what you can run. The automatic transfer switch wins because nobody has to be awake, but it requires a permanently installed standby generator and a device rated for the whole service.
Installation, Permits and Safety
The plate itself is not the hard part. Once compatibility is confirmed, mounting an interlock assembly is commonly reported as a 30 to 45 minute job for someone comfortable with panel work. The difficulty is in choosing correctly, getting the permit and arranging inspection.
The physical sequence is straightforward. Turn the main off and confirm the panel is dead. Mark the generator breaker position using the template or included bit, checking your measured spacing first. Drill the pilot hole with the matched bit, deburr, and test-fit. Remove the branch breakers blocking the required spacing, mounting them lower without over-stretching conductors. Bolt the plate with the shoulder screws, refit the breakers, and confirm the main handle cannot move to ON while the generator breaker is on, and that the reverse also holds.
Then install a proper generator inlet box, run the generator breaker and wiring to that inlet, fit the two-pole breaker in the drilled position, and affix the start-up procedure label so the sequence is visible to anyone opening the cover.
Some jurisdictions require a permit and inspection, and your local authority having jurisdiction decides. Notify your utility beforehand and ask whether they will pull the meter or schedule a shutoff, since the service conductors are still live at the lug even with the main breaker off. Ask the same about reconnecting after the work.
Hire a licensed electrician for the wiring, breaker selection and inspection. A licensed installer can also size the breaker and conductor to your generator output, the step most likely to be wrong in a self-install. Two rules are absolute: never use a male-to-male generator cord, and never defeat, bend or drill out the interlock. Solar with a hybrid power hub needs its own design, because many hubs occupy the breaker position a generator would use.
What an Interlock Kit Installation Actually Costs
Homeowners ask about parts and labor more than anything else here, and the honest answer is that the plate is the smallest part of the bill. Every quote has four components, and labor usually dominates.
First the kit itself, ranging from a low-cost stamped steel plate to a machined aluminum premium part or a factory OEM kit. Second the two-pole generator breaker in the required amperage. Third the generator inlet box plus outdoor housing, conduit and wire run from the panel to the inlet.
Fourth the labor, where the real cost lives: a licensed, bonded and insured electrician removing and refitting branch breakers, drilling the panel under permit, landing the feeder and arranging inspection. Add the permit fee and any utility meter pull on top.
Preparation is how you control that bill. Arrive with your panel identified, spacing measured, generator output known and permit applied for, because every step you skip becomes a line item. If no listed kit fits, a custom MET listed plate adds cost and lead time, so verify fitment before the visit.
Frequently Asked Questions
How to choose a generator interlock kit?
Match the kit to your panel manufacturer and series from the label inside the panel door, then confirm the main breaker amperage, whether the main throws vertically or horizontally, and the center-to-center spacing between the main and the first branch breaker. Buy a plate specified for that exact spacing, and prefer a UL listed or MET listed device for inspection and insurance reasons.
Can I install my own interlock kit?
The plate itself is a straightforward mechanical job once fitment is confirmed, and homeowners report 30 to 45 minutes of mounting work. The wiring, breaker selection and permit are the parts that matter legally, and most jurisdictions require a licensed electrician and an inspection. At minimum, have a licensed electrician review the work before it is energized.
How much does it cost to have a generator interlock kit installed?
Every quote has four parts: the interlock kit, a two-pole generator breaker, a generator inlet box with its outdoor housing and wire run, and electrician labor under permit. Labor usually dominates the invoice. Arrive with your panel identified, spacing measured and permit in hand, since each step you leave undone becomes a line item.
Are generator interlock kits safe?
A listed mechanical interlock is safe because it makes the dangerous state physically impossible: the plate blocks one breaker handle whenever the other is on, with no electronics involved. It is also required by the National Electrical Code, since backfeeding a live utility line can electrocute lineworkers. Unlisted kits often work correctly, but they can complicate an inspection or an insurance claim.
What size breaker should I use for a generator interlock kit?
A 30A double-pole breaker supports roughly 3750 usable watts, enough for essentials such as a refrigerator, lighting and a small pump. A 50A double-pole breaker supports roughly 7600 usable watts and is the correct pairing for a 10,000 watt generator. The generator nameplate, the breaker and the feeder conductor all have to agree.
Conclusion: The Best Generator Interlock Kits for Home Panels in 2026
After comparing ten kits across every major panel family, the Natupal SD200A takes our EDITOR’S CHOICE for the best generator interlock kits for home panels in 2026. It has the largest body of real installs of any kit here, a complete hardware set and a matched drill bit. For Eaton and Cutler Hammer panels the EXCELFU GK-PN200 holds a 4.8 star average across 574 reviews, and the GenSafety BR-200 is the plate to buy if you want machined aluminum that will outlast the panel.
Whatever you choose, identify your panel first. Brand, series, main breaker amperage, throw direction and measured spacing decide everything, and a wrong plate cannot be un-drilled. Spend ten minutes with a tape measure before you spend anything, and have a licensed electrician land the breaker, the inlet and the permit.