Best Interlock Kits for Electrical Panels to Safely Backup Power
Backup power safety is crucial for homes and small businesses. Interlock kits prevent backfeeding and ensure that a generator powers only designated circuits without energizing the main utility feed. The following five interlock kits are compatible with popular GE, Eaton/Cutler Hammer, Siemens/Murray, General Electric vertical, Bryant, Square D, and other panels. This guide highlights what to look for and how each product stacks up for reliable, code-compliant operation during outages.
Summary of chosen products
| Product | Brand | Panel Compatibility | Key Spacing | Primary Benefit |
|---|---|---|---|---|
| Generator Interlock Kit for GE 150/200 Amp Panels (1 1/4″ spacing) | EXCELFU | GE 150/200 Amp | 1 1/4″ | Safe backfeed prevention |
| Eaton Cutler Hammer BR Series 150/200 Amp (1 1/4″ – 1 7/16″) | EXCELFU | BR Series 150/200 | 1 1/4″ – 1 7/16″ | Reliable for BR/CH neutrals |
| Siemens/Murray 150/200 Amp (7/8″ – 1 1/4″) | XMK | Siemens/Murray 150/200 | 7/8″ – 1 1/4″ | Flexible spacing |
| GE Vertical 150/200 Amp (2 1/4″ spacing) | Flngr | GE Vertical 150/200 | 2 1/4″ | Robust vertical integration |
| Square D QO/Homeline 150/200 Amp (1 3/8″) | Natupal | Square D QO/Homeline 150/200 | 1 3/8″ | Easy integration with SD panels |
The information below covers five relevant interlock kits designed to safely route generator power to home circuits while preventing simultaneous main and generator power. Each product section includes a clickable link to the Amazon listing, a visual reference, and a concise feature snapshot to help with quick comparison and decision making.
GE 150/200 Amp Interlock Kit (1 1/4″ Spacing)
Brand: EXCELFU. This interlock kit is designed for General Electric GE 150 or 200 Amp panels. Main breaker to branch breaker spacing is 1 1/4 inches. It prevents both mains and generator power from flowing to the same network, directing generator power safely to dedicated circuits. Suitable for power outages, it supports safe operation of essential appliances while the main feed remains isolated.
Eaton Cutler Hammer BR Series Interlock Kit (1 1/4″ – 1 7/16″ Spacing)
Brand: EXCELFU. Compatible with BR Series and CH-series with plug-in neutral. The design offers a single-handle horizontal throw alignment and a spacing range from 1 1/4″ to 1 7/16″. The kit safely avoids simultaneous main and generator power, enabling reliable backfeed control for emergency backup power, making it a practical choice for homes facing outages.
Siemens/Murray 150/200 Amp Interlock (7/8″ – 1 1/4″ Spacing)
Brand: XMK. This interlock kit supports Siemens/Murray 150 or 200 Amp panels with flexible spacing from 7/8″ to 1 1/4″. It prevents simultaneous power supply from the main and generator, directing generator energy to designated circuits during outages. It is presented as a practical solution to ensure continuity of essential loads and safe operation of household appliances.
GE Vertical 150/200 Amp Interlock (2 1/4″ Spacing)
Brand: Flngr. This interlock kit covers GE vertical panels with a 2 1/4″ spacing between the main and branch breakers. It emphasizes durability through aluminum alloy construction and corrosion resistance. The design aims to maintain safety with a robust interlock mechanism, supporting reliable generator backfeed management in various installation environments.
Square D Type Interlock for 150/200 Amp (1 3/8″ Spacing)
Brand: SPZOCE. Marketed for General Electric GE 150/200 Amp panels with a 1 1/4″ distance or 1 3/8″ spacing between main and branch breakers depending on model, this kit focuses on safe direction of generator power to chosen circuits. It includes installation guidance for wiring and mounting, supporting straightforward, secure operation during outages.
Natupal Interlock for Square D QO/Homeline 150/200 Amp
Brand: Natupal. Compatible with Square D QO or Homeline 150 or 200 Amp panels, spacing at 1 3/8″. The kit is designed to safely connect a generator to a home electrical system while ensuring that all major appliances remain powered as needed. It provides a professional-grade interlock approach for reliable backup power management.
Buying Guide: Key Considerations And Comparisons
Choosing the right interlock kit involves evaluating panel compatibility, spacing, and installation requirements. Here are essential considerations from multiple perspectives to help you decide.
- Panel compatibility: Verify your panel brand and model (GE, Eaton/Cutler Hammer BR, Siemens/Murray, Square D QO/Homeline, Bryant, etc.). The best kit aligns with the specific panel’s main breaker design and layout.
- Spacing between main and generator breakers: Interlock kits specify exact spacing requirements. Incorrect spacing can compromise safety and violate electrical codes. Common ranges include 1 1/4″ to 2 1/4″.
- Installation complexity: Some kits include a drill bit and detailed manuals. Consider your confidence with electrical work and whether you’ll hire a licensed electrician for compliance and warranty.
- Safety and backfeed prevention: The primary purpose is to prevent simultaneous main and generator power, reducing backfeed risk to utility workers and equipment. Look for clear interlock operation and robust materials.
- Durability and material quality: Aluminum alloy or corrosion-resistant finishes improve long-term reliability in various environments, including indoor and outdoor panels.
- Neutral and plug-in configurations: Some brands (BR/CH, QO/Homeline) require specific neutral arrangements. Confirm compatibility with any neutrals or plug-in neutrals in your panel.
- Installation location and panel accessibility: Indoor vs. outdoor mounting, panel access, and existing conduit routes influence kit selection and mounting ease.
- Maintenance and warranty: Check included support materials and warranty terms to protect your investment over time.
- Code compliance: Ensure the kit aligns with local electrical codes and utility requirements for emergency power setups. Using an established interlock kit helps maintain code compliance when installed by a qualified professional.
Across these products, the common thread is a focus on safe, reliable backfeeding control. Evaluating the combination of panel compatibility, precise spacing, and installation practicality will help you choose the kit that best aligns with your home’s electrical system and backup power goals. Whether you prioritize a larger spacing for robust clearance, or a model that emphasizes plug-in neutrals and easy mounting, there are options that fit most standard 150/200 Amp panels.