Power outages can strike at any moment, leaving you in the dark and disrupting your daily life. A portable generator offers a lifeline, but connecting it safely to your home’s electrical panel requires the right equipment. That’s where an interlock kit comes in—a simple, cost-effective device that ensures your generator and utility power never operate simultaneously, protecting you and utility workers.
This guide reviews the top interlock kits on the market, covering compatibility with popular panels like Square D, Eaton, Siemens, and more. Whether you have a 100-amp or 200-amp service, horizontal or vertical throw, we’ll help you find the perfect kit for your setup. Read on to make an informed choice and keep your home powered safely.
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Natupal Generator Interlock Kit Compatible with Square D QO or Homeline 150…
Best forSquare D 150/200 amp panels
- Precise 1 3/8 inch spacing
- Includes safety labels
ConsiderOnly fits Square D panels
Generator Interlock Kit for Eaton Cutler Hammer BR SERIES 150&200amp Panels
Best forEaton BR 150/200 amp panels
- Safe backfeeding prevention
- Easy installation
ConsiderLimited to Eaton BR series
Generator Interlock Kit Compatible with Siemens Murray 150 or 200 Amp Panel
Best forSiemens/Murray 150/200 amp panels
- Smooth operation
- Prevents simultaneous power
ConsiderSpacing must be exact
QYZZRS Generator Interlock Kit Compatible with Square D QO
Best forSquare D QO with easy alignment
- Installation simulation tip
- Safe backfeeding
ConsiderRequires 1 3/8 inch spacing
Generator Interlock Kit for Square D QO or Homeline 100 or 125 Amp Panels
Best forSquare D 100/125 amp panels
- Compact for 100/125 amp
- Smooth movement
ConsiderOnly for 100/125 amp panels
Generator Interlock Kit for Eaton Cutler Hammer BR Series 150&200Amp Panels
Best forEaton BR/CH with drill bit
- Includes drill bit
- Detailed manual
ConsiderOnly for Eaton panels
Generator Interlock Kit for Siemens 100 Amp or Murray 100 Amp Panels
Best forSiemens/Murray 100 amp versatility
- Dual spacing compatibility
- Smooth operation
ConsiderOnly for 100 amp panels
Natupal Generator Interlock Kit Compatible with Square D QO HOM 150 or 200 …
Best forSquare D with updated design
- Updated version
- Complete hardware
ConsiderOnly fits Square D panels
HUBRV Generator Interlock Kit Compatible with Eaton or Cutler Hammer Vertic…
Best forEaton CH vertical throw
- NEC compliant
- Vertical throw fit
ConsiderOnly for CH vertical throw
Generator Interlock Kit fit for Eaton Cutler Hammer CH Series 150 & 200 Amp
Best forEaton CH tan breakers
- Specific tan breaker fit
- Safe backfeeding
ConsiderOnly for tan breakers
Natupal Interlock Kit for Square D QO or Homeline – Reliable Fit
Brand: Natupal
A reliable, safety-focused interlock for Square D panels with all necessary components.
This Natupal interlock kit is designed specifically for Square D QO or Homeline 150 and 200 amp panels, requiring a 1 3/8 inch spacing between the main and generator breaker. That precise measurement ensures a snug, secure fit, so you won’t have to worry about misalignment during installation. The kit includes an interlock plate, three shoulder screws, three hex nuts, a generator start-up procedure label, five reminder labels, and two zip ties—everything you need to get started.
Safety is at the forefront, as the kit prevents both the main and generator breakers from being on at the same time, directing generator power to any circuit in your home without risk. The included labels help you remember the correct start-up sequence, adding an extra layer of protection. If you own a Square D panel and need a dependable interlock, this kit delivers peace of mind.
- Precise 1 3/8 inch spacing
- Includes safety labels
- Complete hardware package
- Only fits Square D panels
- Requires exact spacing
EXCELFU Interlock Kit for Eaton BR – Safe and Cost-Effective
Brand: EXCELFU
A practical, safe interlock for Eaton BR panels that simplifies generator hookup.
This EXCELFU interlock kit is built for Eaton Cutler Hammer BR series panels, including those with plug-in neutral, in 150 and 200 amp configurations. It requires a single handle horizontal throw with left-to-right operation and a spacing of 1 1/4 to 1 7/16 inches between the main and branch breakers. This compatibility ensures a straightforward installation process, letting you connect your generator quickly.
The kit’s primary function is to provide a safe and cost-effective way to backfeed your home’s electrical appliances using a portable generator. It guarantees that the main breaker can never be on while the generator breaker is active, eliminating the risk of dangerous backfeeding. For Eaton BR panel owners, this interlock offers both safety and affordability, making it a smart choice for emergency power.
- Safe backfeeding prevention
- Easy installation
- Cost-effective solution
- Limited to Eaton BR series
- Spacing must be verified
XMK Interlock Kit for Siemens Murray – Smooth Operation
Brand: XMK
A dependable interlock for Siemens and Murray panels with smooth, safe performance.
Designed for Siemens and Murray 150 or 200 amp panels, this XMK interlock kit requires a spacing of 7/8 to 1 1/4 inches between the main and branch breakers. The kit ensures that you check your panel’s model and spacing before purchase, which is crucial for a proper fit. Once installed, it moves smoothly during operation, providing a hassle-free experience.
Safety is a key feature, as the interlock prevents both the main and generator power from being active at the same time. This protects your home’s electrical system and ensures compliance with safety standards. If you have a Siemens or Murray panel and want a reliable interlock that operates fluidly, this kit is a solid option.
- Smooth operation
- Prevents simultaneous power
- Easy to install
- Spacing must be exact
- Not for other brands
QYZZRS Interlock Kit for Square D QO – Easy Alignment
Brand: QYZZRS
A user-friendly interlock with clear installation guidance for Square D panels.
This QYZZRS interlock kit is compatible with Square D QO and Homeline 150 and 200 amp panels, requiring a 1 3/8 inch spacing between the main and generator breaker. The manufacturer provides an installation note: attach the screws to the interlock kit first and simulate the test to better align the installation. This thoughtful guidance helps avoid common mistakes and ensures a smooth setup.
The kit acts as a manual transfer switch, allowing safe backfeeding of power from a portable generator to your distribution panel and home lines. It effectively prevents utility and generator supplies from being connected simultaneously, which is essential for safety. If you’re looking for an interlock that prioritizes easy installation and safety, this QYZZRS model is worth considering.
- Installation simulation tip
- Safe backfeeding
- Compatible with QO/Homeline
- Requires 1 3/8 inch spacing
- Only for Square D panels
XMK Interlock Kit for Square D 100/125 Amp – Compact Fit
Brand: XMK
A reliable interlock for smaller Square D panels, ensuring safe generator use.
This XMK interlock kit is tailored for Square D QO or Homeline panels rated at 100 and 125 amps, making it ideal for smaller homes or subpanels. It requires a single handle horizontal throw with left-to-right operation and a spacing of 3/4 to 7/8 inches between the main and branch breakers. This compact design ensures a precise fit for your specific panel size.
Safety and reliability are at the core, providing a cost-effective way to backfeed your home’s electrical appliances with a portable generator. The interlock ensures the main breaker can never be on while the generator breaker is on, and it moves smoothly during operation. For those with a 100 or 125 amp Square D panel, this kit offers a secure and straightforward solution.
- Compact for 100/125 amp
- Smooth movement
- Safe backfeeding
- Only for 100/125 amp panels
- Spacing must be verified
SPZOCE Interlock Kit for Eaton BR – Includes Drill Bit
Brand: SPZOCE
A comprehensive interlock kit with added convenience for Eaton panel owners.
This SPZOCE interlock kit is compatible with Eaton Cutler Hammer BR series (with plug-in neutral) and CH series (with plug-in neutral) panels in 150 and 200 amp configurations. A standout feature is the inclusion of a 3/16-inch drill bit made of sturdy steel, which can easily penetrate the breaker panel. This saves you a trip to the hardware store and simplifies the installation process.
The kit comes with a detailed installation manual, ensuring you have clear instructions every step of the way. Safety is paramount, as it prevents accidental power outages by safely directing generator power to any circuit in your home. The package includes an interlock plate, three screws and nuts, and the drill bit, making it a comprehensive solution for Eaton panel owners.
- Includes drill bit
- Detailed manual
- Safe power direction
- Only for Eaton panels
- Drill bit may not fit all
XMK Interlock Kit for Siemens 100 Amp – Versatile Fit
Brand: XMK
A versatile interlock for 100 amp Siemens and Murray panels with flexible fitting.
Designed for Siemens and Murray 100 amp panels, this XMK interlock kit offers flexibility with a spacing of 7/8 inch for plug-on neutral panels and 1 1/4 inch for non-plug-on neutral panels. This dual compatibility makes it a versatile choice for various panel configurations. It’s essential to verify your panel’s model and spacing to ensure a proper fit.
The kit’s primary function is to prevent both main and generator power from being active simultaneously, safely directing generator power to your home. It moves smoothly during operation, providing a reliable and easy-to-use solution. If you have a 100 amp Siemens or Murray panel, this interlock offers the adaptability you need.
- Dual spacing compatibility
- Smooth operation
- Safe power prevention
- Only for 100 amp panels
- Spacing must be checked
Natupal Interlock Kit Update Version – Enhanced Safety
Brand: Natupal
An updated, reliable interlock for Square D panels with enhanced safety features.
This updated version of the Natupal interlock kit is compatible with Square D QO or Homeline 150 and 200 amp panels, maintaining the 1 3/8 inch spacing requirement between the main and generator breaker. The ‘update versioner’ suggests refinements for improved performance and reliability. It includes the same comprehensive package: interlock plate, shoulder screws, hex nuts, start-up procedure label, reminder labels, and zip ties.
Safety remains a top priority, as the kit prevents both main and generator power from being on at the same time, directing generator power safely to any circuit. The included labels help you follow the correct start-up sequence, reducing the risk of errors. For Square D panel owners seeking a dependable interlock with added refinements, this Natupal version is a strong contender.
- Updated version
- Complete hardware
- Safety labels included
- Only fits Square D panels
- Requires exact spacing
HUBRV Interlock Kit for Eaton CH Vertical – NEC Compliant
Brand: HUBRV
A specialized, NEC-compliant interlock for vertical throw Eaton CH panels.
This HUBRV interlock kit is specifically designed for Eaton or Cutler Hammer vertical throw CH series CH5 panels in 150 or 200 amp configurations, requiring a 2 1/4 inch spacing between the main and generator breaker. The vertical throw design is unique, catering to panels that operate differently from standard horizontal throw models. This specialization ensures a precise fit for your specific panel type.
Safety is emphasized with compliance to NEC regulations such as NEC 230.85 and NEC 702.7, preventing main power and generator from being on simultaneously. This protects utility workers and your equipment from dangerous backfeeding. For homes with generators and vertical throw CH panels, this interlock is an essential safety device that prevents electrical accidents and equipment damage.
- NEC compliant
- Vertical throw fit
- Prevents accidents
- Only for CH vertical throw
- Requires 2 1/4 inch spacing
XMK Interlock Kit for Eaton CH – Tan Breaker Fit
Brand: XMK
A precise interlock for Eaton CH panels with tan breakers, ensuring safe operation.
This XMK interlock kit is compatible with Eaton Cutler Hammer CH series 150 and 200 amp panels, but specifically only for CH panels with TAN breakers. It requires a single handle horizontal throw with left-to-right operation and a spacing of 1 1/2 inches between the main and branch breakers. This precise specification ensures a secure fit for your panel.
The kit provides a safe and cost-effective way to backfeed your home’s electrical appliances using a portable generator. It ensures the main breaker can never be on while the generator breaker is active, preventing dangerous situations. If you have an Eaton CH panel with tan breakers and need a reliable interlock, this XMK model is designed for you.
- Specific tan breaker fit
- Safe backfeeding
- Easy installation
- Only for tan breakers
- Requires 1 1/2 inch spacing
Buyer’s Guide: What to Consider
Choosing the right interlock kit is essential for safe generator use. Here are key factors to consider to ensure you select a kit that fits your panel and meets safety standards.
- Panel Compatibility: Ensure the interlock kit matches your panel brand and model. Kits are specific to brands like Square D, Eaton, Siemens, and Murray, and often to series like QO, Homeline, BR, or CH. Check your panel's label to confirm compatibility before purchasing.
- Spacing Measurement: Measure the distance between the main breaker and the branch breaker where the generator breaker will be installed. Kits specify required spacing, such as 1 3/8 inches or 7/8 to 1 1/4 inches. Accurate measurement is crucial for a proper fit and safe operation.
- Breaker Throw Type: Determine whether your main breaker is horizontal throw (left-right) or vertical throw (up-down). Most kits are designed for horizontal throw, but some panels, like certain CH series, use vertical throw. Select a kit that matches your breaker's orientation.
- Amp Rating: Match the interlock kit to your panel's amp rating, typically 100, 125, 150, or 200 amps. Kits are often designed for specific ranges, so verify that your panel's rating falls within the kit's compatibility to ensure a secure fit and proper functionality.
- Installation Requirements: Consider the installation process. Some kits include additional items like drill bits or detailed manuals, which can simplify the job. Also, check if the kit requires specific tools or if there are any special instructions, such as attaching screws first for alignment.
Conclusion
Selecting the best interlock kit for your home involves matching the kit to your panel’s brand, model, amp rating, and breaker spacing. Whether you have a Square D, Eaton, Siemens, or Murray panel, there are reliable options available that prioritize safety and ease of installation. Always double-check your panel’s specifications before purchasing to avoid compatibility issues.
For most homeowners, the Natupal kits for Square D panels and the XMK kits for Siemens and Eaton panels offer excellent value and safety. If you have a vertical throw CH panel, the HUBRV kit is a specialized choice. Whichever you choose, an interlock kit is a smart investment for safe and convenient generator power during outages.
Erica Steven is the founder and lead writer of WorstBrands, a site dedicated to providing honest and trustworthy reviews about outdoor gear and fashion products.
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