Best Interlock for Electrical Panels: Safe Generator Backfeeding Kits
Find the right interlock for your electrical panel to safely backfeed a generator during outages. This guide highlights five generator interlock kits that fit common GE, Eaton/Cutler Hammer, Square D, and other 150–200 amp panels. Best for homeowners planning reliable backup power without backfeed risks, contractors installing temporary back-up power, and DIY enthusiasts seeking a straightforward, code-adherent solution. The top picks emphasize safety, ease of installation, and clear spacing between main and branch breakers.
Summary table of chosen products
| Product | |||
|---|---|---|---|
| Flngr Generator Interlock Kit (GE 150/200 Amp) | GE Vertical Panels | 2 1/4 | |
| EXCELFU Generator Interlock Kit (Eaton BR 150/200) | Eaton Cutler Hammer BR/CH series | 1 1/4 – 1 7/16 | |
| QYZZRS Interlock Kit (Eaton 100/125) | Eaton Cutler Hammer 100/125 | — | |
| SPZOCE Interlock Kit (GE 150/200) | GE 150/200 Amp Panels | 1 1/4 | |
| Natupal Interlock Kit (Square D QO/Homeline 150/200) | Square D QO/Homeline 150/200 | 1 3/8 |
Flngr Generator Interlock Kit for GE Panels
Features include compatibility with General Electric vertical 150 or 200 amp panels and a 2 1/4 inch spacing between main and branch breakers. The kit prevents simultaneous mains and generator power, guiding generator power to home circuits safely. Best for GE panel owners seeking a straightforward, professional-grade interlock solution. A potential limitation is ensuring model and spacing match before purchase.
EXCELFU Interlock Kit for Eaton BR/CH Series
Safe and reliable backfeeding for Eaton Cutler Hammer BR/CH series, suitable for 150 and 200 amp panels. Spacing ranges from 1 1/4 to 1 7/16 inches between main and branch breakers. Best for Eaton-branded installations where a robust, cost-effective interlock is needed. Choose this if you have a BR/CH panel and want clear installation guidance; note the exact spacing should match your panel for proper fit.
QYZZRS Interlock Kit for Eaton 100/125 Amp Panels
Designed for Eaton Cutler Hammer 100 and 125 amp panels, including a complete kit with screws, drill bit, and labels. Best for smaller-capacity installations or wrap-around projects where space is at a premium. A caution is to follow installation simulations carefully to align the interlock position and avoid improper fit.
SPZOCE Interlock Kit for GE 150/200 Amp Panels
Compatible with GE 150 or 200 amp panels, featuring a 1 1/4 inch spacing between main and branch breakers. Includes a drill bit and manual for easier installation. Best for GE users who want a practical, easy-to-install solution. Limitation: some panels may require verification of model compatibility beyond generic GE 150/200 amp labeling.
EXCELFU Interlock Kit for GE Panels
Geared toward General Electric GE 150 or 200 amp panels, with a 1 1/4 inch spacing between main and branch breakers. Best for GE owners who want a safe, reliable interlock to prevent simultaneous mains and generator power. A potential drawback is ensuring compatibility with your exact GE panel model and spacing requirement.
Natupal Interlock Kit for GE 100 Amp Panels
Compatible with GE 100 amp panels, featuring a 1 3/8 inch spacing between the main and generator breaker. Best for smaller GE installations or where 100 amp service is in use. Choose this if your panel is 100 amp and you need a compact, clearly spaced interlock. Limitation: higher amperage panels may require a different kit.
Natupal Interlock Kit for Square D QO/Homeline
Designed for Square D QO or Homeline 150/200 amp panels with a 1 3/8 inch spacing between main and generator breaker. Best for Square D installations requiring a precise spacer and clear installation steps. Avoid this if your panel is not from Square D or does not match the 150/200 amp configuration.
Buying Guide
Key considerations when choosing an interlock kit:
- Panel compatibility: Confirm the exact panel model and brand (GE, Eaton, Square D, etc.) and the required spacing between mains and generator breakers.
- Amperage rating: Ensure the kit supports your panel’s amp rating (100, 150, or 200 amps) and your intended generator output.
- Installation access: Some kits include a drill bit and installation manual—assess whether you have the tools and skill to install safely.
- Safety features: Look for designs that prevent simultaneous mains and generator power and provide clear labeling or test procedures.
- Space requirements: Measure existing breaker layout to confirm there is adequate clearance for the interlock mechanism.
- Ease of use: Consider how the interlock affects daily operation during outages and whether switching is straightforward.
FAQ
- What is an interlock kit for electrical panels?
It is a device that safely prevents backfeeding from a generator to the utility mains by ensuring only one power source is connected at a time.
- Do I need a professional to install an interlock kit?
Installation involves working inside the breaker panel. If you are not confident with electrical work, consult a licensed electrician.
- Can I use any interlock kit with any panel?
No. Interlock kits are panel- and amp-specific. Verify compatibility with your panel model and spacing requirements.
- Will an interlock kit work with a portable generator?
Yes, when installed correctly, it allows safe backfeeding of generator power to selected circuits during outages.
- Is the exact spacing critical?
Yes. Correct spacing ensures the interlock engages properly and avoids misalignment that can compromise safety.
- Can I install the kit myself if I have the right tools?
If you have electrical training and follow the manufacturer instructions, a careful DIY installation may be possible. Otherwise, hire a pro.