When running a portable generator as a backup power source, safely interlocking the main panel with the generator breaker is essential. Panel interlock kits prevent backfeeding and help comply with NEC guidelines, protecting both occupants and utility workers. This article reviews five top interlock kits designed for common panel brands and models, highlighting space requirements, compatibility, and installation considerations to support an informed purchase.
| Product | Brand | Panel Type | Spacing | Why It Stands Out |
|---|---|---|---|---|
| ExcelFu Generator Interlock Kit | EXCELFU | Eaton BR Series 150/200 A | 1 1/4″ – 1 7/16″ | Solid compatibility with BR/CH, safe dual-breaker operation |
| Natupal Interlock Kit for Square D QO/Homeline | Natupal | Square D QO/Homeline 150/200 A | 1 3/8″ | Broad Square D compatibility, reliable safety features |
| WHXMHRQ Interlock Kit for Square D QO/Homeline | WHXMHRQ | Square D QO/Homeline 150/200 A | 1 3/8″ | Sturdy steel build; easy installation |
| QYZZRS Interlock Kit for Eaton BR/CH | QYZZRS | Eaton Cutler Hammer BR/CH 150/200 A | 1 1/4″ – 1 7/16″ | Offers precise spacing and install guidance |
| XMK Interlock Kit for Siemens/Murray | XMK | Siemens/Murray 150/200 A | 7/8″ – 1 1/4″ | Flexible spacing and compatible models |
Note: Spacing between the main breaker and generator breaker is a critical specification. Always verify model compatibility and required gap before purchasing or installing an interlock kit. This guide emphasizes products that cover popular panel families like Eaton, Square D, Siemens/Murray, and more.
ExcelFu Generator Interlock Kit for Eaton BR Panels
The ExcelFu interlock kit is designed for Eaton Cutler Hammer BR series panels, including 150 and 200 amp options. It provides a safe, cost-effective solution to backfeeding by a portable generator, allowing a single main switch to coordinate with a generator breaker. The stated spacing between the main and branch breakers is 1 1/4 to 1 7/16 inches. The kit supports a single-handle horizontal throw, enabling a clear on/off action and reducing the risk of simultaneous generator and main power. Installation notes emphasize ensuring proper alignment with the interlock plate screws and verifying compatibility with plug-in neutral configurations in BR and CH series where applicable.
Key considerations:
– Compatibility with BR and CH panels; verify model number and neutral configuration.
– Space requirement: 1 1/4″ – 1 7/16″ between main and generator breakers.
– Installation complexity: typically medium; a drill and level alignment are involved.
Natupal Interlock Kit for Square D QO/Homeline
The Natupal interlock kit is compatible with Square D QO or Homeline 150/200 amp panels. It requires a 1 3/8 inch spacing between the main and generator breaker. The kit is positioned as a practical safety device to direct generator power safely to any household circuit during outages, ensuring essential appliances stay operable. Installation guidance stresses proper screw attachment of the interlock and careful alignment to avoid misplacement that could hinder operation.
Key considerations:
– Broad Square D compatibility (QO/Homeline).
– Spacing: 1 3/8 inches.
– Emphasis on safe operation during outages and appliance continuity.
WHXMHRQ Interlock Kit for Square D Panels
WHXMHRQ offers an interlock kit compatible with Square D QO and Homeline 150/200 amp panels. The kit specifies a spacing of 1 3/8 inches between the main breaker and the generator breaker. Construction notes indicate a sturdy steel build and an included drill bit to facilitate installation. The manufacturer highlights safe operation to prevent simultaneous energization of the main and generator, aligning with standard NEC safety practices.
Key considerations:
– Square D QO/Homeline compatibility.
– Spacing: 1 3/8 inches.
– Included hardware and guidance for alignment and install simulation.
QYZZRS Interlock Kit for Eaton BR/CH Panels
The QYZZRS interlock kit is designed for Eaton Cutler Hammer BR and CH series panels at 150/200 amp. It specifies a spacing range of 1 1/4 to 1 7/16 inches between the main and generator breakers. Installation notes emphasize attaching screws to the interlock first and simulate the alignment to avoid installation errors. The package typically includes a plate, screws, drill bit, and instructional materials to guide startup procedures and labeling for safe operation during outages.
Key considerations:
– Compatibility with BR/CH panels.
– Spacing range: 1 1/4″ – 1 7/16″.
– Comprehensive installation hardware included, with guidance on startup procedures.
XMK Interlock Kit for Siemens/Murray Panels
The XMK interlock kit pairs with Siemens and Murray 150/200 amp panels, offering a spacing range of 7/8″ to 1 1/4″ between main and branch breakers. This kit is positioned as a versatile option when standard spacing falls within the 7/8 to 1 1/4 inch window. The description emphasizes safe operation to prevent simultaneous mains and generator power, enabling safe distribution to home circuits during outages. Installation guidance recommends measuring spacing and following alignment steps to ensure proper function.
Buying Guide: Key Purchase Considerations
- Panel compatibility: Interlock kits are brand- and model-specific. Verify the panel family (BR, CH, QO, Homeline, Siemens/Murray) and the exact amperage (150/200 A are common for these products).
- Spacing accuracy: The critical parameter is the distance between the main and generator breakers. Most kits list a precise range (e.g., 1/4″ to 1 7/16″, or 1 3/8″), so confirm your panel’s spacing before purchase.
- Installation complexity: Some kits include drill bits and detailed instructions; others may require professional electrical work. Assess your experience and local code requirements.
- Safety and compliance: Interlock kits are designed to prevent backfeeding and to meet NEC guidelines for safe operation during outages. Ensure the kit’s construction materials (steel, plating) and mounting hardware support durable, long-term use.
- Component packaging: Many listings include screws, drill bits, labels, and startup procedure references. A complete package reduces extra shopping trips.
- Upgrade considerations: If you plan to upgrade panels or switch brands, verify future compatibility or plan to replace related interlock components accordingly.
- Warranty and support: Check manufacturer warranties and available technical support for installation guidance and troubleshooting.
In summary, selecting a generator interlock kit requires aligning panel brand and amperage with the correct spacing and installation requirements. The five products featured here provide options across Eaton, Square D, Siemens/Murray, and BR/CH configurations, helping homeowners maintain safe, NEC-compliant backup power during outages without risking backfeed hazards.