Best Generator Interlock Kits for Seamless Backup Power
If you’re planning a safe, code-compliant way to run essential home circuits during a power outage, a generator interlock kit is a smart choice. These kits coordinate the main and generator breakers to prevent backfeeding and ensure critical loads stay powered. They’re best for homeowners who want a reliable, hard-wired transfer approach without a separate transfer switch. The top options below cover Square D, Eaton/Cutler Hammer, GE, Siemens/Murray, and Homeline configurations. This guide highlights who each product is best for and why it’s a solid pick for backup power readiness.
| Product | Best For | |
|---|---|---|
| Natupal Generator Interlock Kit for Square D QO/Homeline | Square D QO/Homeline 150–200A panels | 1 3/8 in |
| EXCELFU Eaton BR Series Interlock Kit | Eaton/Cutler Hammer BR 150–200A | 1 1/4–1 7/16 in |
| LATING GE General Electric Single Vertical Throw | GE/General Electric 2-pole style panels | 2 1/2 in |
| S7 Homeline Main Breaker Interlock | Square D Homeline 150–225A | 2-pole arrangement varies by panel |
| XMK Siemens/Murray 100–200A Interlock | Siemens/Murray 100–200A panels | 7/8 in to 1 1/4 in |
Natupal Interlock Kit for Square D QO/Homeline
Best for homeowners with Square D QO or Homeline panels seeking a straightforward backfeed prevention solution. This kit offers 1 3/8 inch spacing between the main and generator breaker, ensuring safe connection of generator power to any circuit. It’s suitable for 150 or 200 amp panels and emphasizes DIY-friendly installation with professional-grade safety assurance.
Who it’s best for: a user upgrading an existing Square D panel to support portable generator backup without a separate transfer panel. Why selected: compatibility with common QO/Homeline configurations and clear spacing specification simplifies planning and installation.
Caution: verify panel model and breaker layout before purchase to ensure the kit matches your exact panel spacing and main breaker position.
EXCELFU Generator Interlock Kit for Eaton BR Series
Best for Eaton/Cutler Hammer residential panels needing a backfeed-safe solution. This interlock kit supports BR 150–200 amp panels, with a spacing range of 1 1/4 to 1 7/16 inches between the main and branch breakers. It provides a cost-effective, reliable path for portable generators during outages.
Who it’s best for: homeowners with Eaton BR panels seeking a compact interlock option. Why selected: broad compatibility within the BR series and explicit spacing range for precise installation.
Caution: confirm your exact main-breaker position and spacing on the panel before ordering to avoid fit issues.
S7 Homeline Main Breaker Interlock Kit
Best for Square D Homeline users needing no separate generator panel. This kit interlocks the QOM1/QOM2 main breaker with a 2-pole generator breaker, aiding in preventing both power sources from being active simultaneously during backup operations. It works with Homeline 150A–225A centers and is compatible with HOMCGK2C covers in interlock configurations.
Who it’s best for: homeowners with Homeline panels who want a space-saving backup setup that integrates with existing equipment. Why selected: no extra panel required and clear compatibility notes for Homeline centers.
Caution: verify panel model and spacing before purchase to ensure full compatibility with your Homeline configuration.
XMK Siemens/Murray Interlock Kit 100A
Best for Siemens/Murray panels in need of a safe, economical interlock solution for 100A service. The kit supports 7/8 inch spacing for Plug-on Neutral models and 1 1/4 inch spacing for non-Plug-on Neutral models. It ensures mains and generator power do not backfeed into the home simultaneously.
Who it’s best for: users with Siemens/Murray panels who require precise spacing options. Why selected: flexible spacing configuration and a straightforward approach to safe generator backfeeding.
Caution: double-check the exact model and spacing for your specific Siemens/Murray panel to ensure proper fit and function.
XMK Siemens/Murray 150–200A Interlock Kit
Best for larger Siemens/Murray installations needing a 150–200A interlock option. The kit supports 7/8 to 1 1/4 inch spacing between main and branch breakers. It is designed to prevent simultaneous energization of utility power and generator power, enabling safe operation during outages.
Who it’s best for: homeowners upgrading medium-to-large Siemens/Murray panels. Why selected: wide compatibility across 150–200A panels and clear spacing guidance.
Caution: confirm exact panel model and spacing prior to purchase to ensure compatibility and proper installation.
Natupal Interlock Kit for GE 100 Amp Panels
Best for GE 100 amp panels requiring a compact, reliable interlock solution. The kit specifies 1 3/8 inch spacing between the main and generator breaker and focuses on safe direct power transfer to essential circuits during outages.
Who it’s best for: GE panel owners seeking a lightweight integration with generator backup. Why selected: simple spacing specification and GE compatibility.
Caution: verify that your GE panel is indeed a 100A model and that the spacing matches 1 3/8 inches before purchase.
Buying Guide: Key Purchase Considerations
- Panel compatibility: Confirm your panel brand, model, and amperage (100A, 150A, 200A, etc.) before selecting an interlock kit.
- Spacer spacing: Different kits require specific gaps between the main breaker and generator breaker (ranges from 7/8 in to 2 1/2 in). Measure your panel’s available space to ensure fit.
- Ease of installation: Some kits are more DIY-friendly, while others may benefit from professional installation to ensure code compliance.
- Safety features: Look for interlocks designed to prevent backfeeding, accidental dual-power energization, and secure mechanical engagement.
- Panel access and layout: Consider whether you want a kit that works with your existing cover or requires a specific interlock-compatible cover.
Frequently Asked Questions
- What is a generator interlock kit used for?
It prevents backfeeding and ensures that the utility and generator power cannot be on at the same time, enabling safe backup power for selected circuits.
- Do interlock kits require a transfer switch?
No. Interlock kits provide a safe alternative to a separate transfer switch by coordinating breakers within the existing panel.
- Can I install an interlock kit myself?
Many kits are designed for DIY installation, but it depends on the panel and your comfort with electrical work. Always follow the manufacturer’s instructions and local codes.
- How do I choose the right spacing for my interlock kit?
Check your panel’s main and generator breaker positions. The kit’s spacing must match the gap between breakers to ensure safe operation.
- Is a specific brand more reliable for interlock kits?
Quality and compatibility matter more than brand. Choose a kit that explicitly lists your panel model and amperage, and verify installation requirements.