Best Generator Interlock Kit for Safe Backup Power
If you’re looking to safely backfeed a portable generator into a home electrical system, a generator interlock kit is essential. These five options are well-suited for 150 and 200 amp panels from Square D, Eaton, Siemens/Murray, and compatible brands. They help prevent both mains and generator power from running at the same time, reducing the risk of backfeed and protecting appliances. This guide targets homeowners planning backup power, DIY installers, and professionals seeking reliable installation compatibility.
| Product | Brand | Compatible Panels | Spacing (Main to Generator) |
|---|---|---|---|
| Natupal Generator Interlock Kit SD200A | Natupal | Square D QO or Homeline 150/200A | 1 3/8 inches |
| Generator Interlock Kit for Square D QO/Homeline 150/200A | QYZZRS | Square D QO and Homeline 150/200A | 1 3/8 inches |
| BR Series Interlock Kit for Eaton Cutler Hammer 150/200A | EXCELFU | Eaton Cutler Hammer BR/CH 150/200A | 1 1/4 – 1 7/16 inches |
| Siemens/Murray Interlock Kit 150/200A | XMK | Siemens/Murray 150/200A | 7/8 – 1 1/4 inches |
| Square D QO/Homeline 150/200A Interlock Kit | SPZOCE | Square D QO or Homeline 150/200A | 1 3/8 inches |
Natupal Interlock Kit SD200A for Square D Panels
The Natupal interlock kit is designed for Square D QO or Homeline panels at 150 or 200 amps. It specifies a required 1 3/8 inch spacing between the main breaker and the generator breaker. This kit is described as a safe method to direct generator power to home circuits while maintaining access to essential loads. Best for DIY homeowners with Square D panels seeking a straightforward installation.
Who it’s best for: Homeowners with QO or Homeline 150/200A panels seeking a compliant backfeed solution. Why selected: clear compatibility, documented spacing, and a straightforward installation approach. Caution: installation requires precise alignment; follow the included steps to avoid positioning errors.
Generator Interlock Kit for Square D QO/Homeline 150/200A (1 3/8″ Spacing)
QYZZRS offers an interlock kit compatible with Square D QO and Homeline panels at 150 and 200 amps, with the same 1 3/8 inch spacing requirement. It emphasizes careful installation prep, including screws positioning and alignment. Best for those who want a clearly documented preparation process and a focus on compatibility with popular Square D configurations.
Who it’s best for: Square D panel owners who value explicit installation steps. Why selected: strong emphasis on correct alignment before final installation. Caution: follow the simulation steps to avoid misalignment during mounting.
EXCELFU BR Series Interlock Kit for Eaton 150/200A
This interlock kit is designed for Eaton Cutler Hammer BR/CH series at 150 and 200 amps. It notes a spacing range of 1 1/4 to 1 7/16 inches between the main and branch breakers. It includes a drill bit and installation manual to aid DIY installers. Best for Eaton BR panel users who want a compact, reliable backfeed option.
Who it’s best for: Homeowners with BR/CH panels seeking a cost-effective, install-friendly kit. Why selected: explicit spacing range and included installation tools. Caution: ensure your panel uses a plug-in neutral configuration if it applies to your model.
SPZOCE BR/CH Interlock Kit for Eaton 150/200A
The SPZOCE interlock kit is compatible with Eaton Cutler Hammer BR and CH series for 150 and 200 amp panels. It specifies a spacing of 1 1/4 to 1 7/16 inches and includes a 3/16-inch drill bit for installation. Best for Eaton BR/CH users who want a complete package with drilling tools. Caution: verify your exact panel series and neutral configuration before ordering.
SPZOCE Interlock Kit for Square D QO/Homeline 150/200A
The SPZOCE interlock kit for QO and Homeline panels mirrors the 1 3/8 inch spacing requirement and is presented as a compatible option for 150 and 200 amp configurations. It emphasizes ease of installation with a steel drill bit and a detailed manual. Best for Square D users who want a ready-to-install, documented kit. Caution: ensure model compatibility with your specific panel series and main breaker layout.
Buying Guide: Key Considerations for Generator Interlock Kits
- Panel compatibility: Confirm your panel brand (Square D, Eaton/Cutler Hammer, Siemens/Murray) and amperage (150/200A) match the interlock kit’s listed compatibility.
- Spacing accuracy: Most kits require a precise main-to-generator breaker spacing (commonly 1 3/8 inches or 1 1/4-1 7/16 inches). Measure your panel before purchasing.
- Installation ease: Look for kits that include installation manuals, alignment aids, and drill bits. Some kits provide simulated setup steps to prevent misplacement.
- Safety and compliance: Interlocks prevent simultaneous main and generator power, protecting appliances and reducing backfeed risk. Verify the kit is designed for safe generator backfeeding in your region and panel model.
- Tools and hardware: Ensure the kit includes required screws, alignment pieces, and a drill bit. Some kits require a specific type of neutral connection; verify compatibility with plug-in neutral panels if applicable.
- Professional assistance: If you’re uncertain about panel wiring or backfeed setups, consider hiring a licensed electrician to perform the installation and ensure code compliance.
- Maintenance and spare parts: Check for availability of replacement screws, bits, or minor components and the manufacturer’s support options.
FAQ
- What is a generator interlock kit?
An interlock kit is a device that ensures the main power and generator power cannot be on at the same time, enabling safe backfeeding to supply selected circuits during an outage.
- Which panels are most commonly supported by these kits?
Square D QO/Homeline, Eaton Cutler Hammer BR/CH, and Siemens/Murray 150/200A panels are frequently listed as compatible models.
- Do interlock kits require professional installation?
Not always, but installation involves panel access and precise alignment. A licensed electrician is recommended for safety and code compliance if you are unsure.
- What spacing should I look for in a kit?
Typical spacings are 1 3/8 inches or a range around 1 1/4 to 1 7/16 inches between the main and generator breaker, depending on the model.
- Can I reuse an old panel or change panel types after installing an interlock?
Interlocks are panel-specific. Replacing or reconfiguring panels typically requires new interlock kits and verification by a professional.
- What safety benefits do interlock kits provide?
They prevent backfeeding, reduce arc risk, and protect both the home wiring and the generator from accidental simultaneous power sources.