If you need a reliable interlock kit to safely backfeed a portable generator, these options cover common panel brands and amperages. They are best for homeowners who want a code-compliant, safe alternative to direct generator backfeed. Choose by your panel type and spacing needs, then verify compatibility with your main breaker and branch configurations. The following picks are suited for different systems, from Siemens/Murray to Square D, Eaton, and GE panels.
| Product | Brand | Panel Type | Spacing | Best For |
|---|---|---|---|---|
| Generator Interlock Kit Compatible with Siemens or Murray 150/200 Amp Panels | XMK | Siemens/Murray 150–200 A | 7/8″ – 1 1/4″ | Siemens/Murray users seeking safe backfeed |
| Generator Interlock Kit for Square D QO or Homeline 150/200 A | QYZZRS | Square D QO/Homeline 150–200 A | 1 3/8″ | Square D users needing precise spacing |
| Natupal Generator Interlock Kit for Square D QO/Homeline 150/200 A | Natupal | Square D QO/Homeline 150–200 A | 1 3/8″ | Economical Square D option |
| EXCELFU Interlock for Eaton BR 150/200 A | EXCELFU | Eaton Cutler Hammer BR 150/200 A | 1 1/4″ – 1 7/16″ | Eaton BR series users |
| EXCELFU GE 150/200 A Interlock | EXCELFU | General Electric GE 150/200 A | 1 1/4″ | GE panel users needing reliable interlock |
XMK Siemens/Murray 150/200 A Interlock Kit
This interlock kit fits Siemens or Murray panels rated at 150 or 200 amps. It features a 7/8 to 1 1/4 inch spacing between the main and branch breakers. Best for homeowners with Siemens/Murray systems seeking a rugged, code-compliant solution. The kit is designed to safely prevent simultaneous mains and generator power, directing generator output to selected circuits while protecting household appliances. A limitation to note is to confirm model compatibility and spacing before purchase to avoid incorrect installation.
QYZZRS Interlock Kit for Square D QO/Homeline
Designed for Square D QO and Homeline 150/200 amp panels, this kit uses a 1 3/8 inch spacing between the main and generator breaker. It’s a solid option for Square D homes requiring precise alignment during installation. The kit includes mounting screws and alignment guidance to reduce setup errors. Best for Square D users who want a straightforward, professional interlock. Caution: follow the included installation notes to avoid misalignment and improper operation.
Natupal Interlock Kit for Square D QO/Homeline
Natupal offers a Square D QO/Homeline 150/200 amp interlock with a 1 3/8 inch spacing between the main and generator breaker. It is suitable for users seeking a dependable interlock that enables safe distribution of generator power to home circuits. Best for Square D environments needing a cost-conscious option. A potential limitation is ensuring the kit matches the exact panel model and spacing before installation.
QYZZRS Eaton Cutler Hammer 100/125 A Interlock
QYZZRS provides an interlock kit for Eaton Cutler Hammer 100/125 amp panels. The kit includes screws, a drill bit, and start-up labels to aid installation. Best for smaller Eaton panels where a compact interlock is needed to safely backfeed a generator. Use with caution: verify the kit contains all required hardware and that your panel supports a plug-in neutral configuration if applicable.
EXCELFU BR Series 150/200 A Interlock
This Eaton Cutler Hammer BR interlock kit supports BR 150/200 amp panels. It describes a safe backfeed method for portable generators to power selected circuits. Best for BR series users seeking a reliable, cost-effective backup power option. A limitation could be spacing range and compatibility with certain CH-series panels that require a different approach.
EXCELFU GE 150/200 A Interlock
EXCELFU offers a GE 150/200 amp interlock kit. It safely prevents backfeeding by coordinating mains and generator power, allowing generator-assisted operation of home circuits. Best for GE panel owners who want a straightforward installation. Caution: confirm that your GE panel model aligns with the kit’s spacing and mounting requirements.
Buying Guide
What should I check before buying an interlock kit?
Panel compatibility is the top priority. Confirm your panel brand, model, and amperage rating (150/200 A are common). Verify the required spacing between the main and generator or branch breakers (options range from 7/8″ to 4″ in various kits).
Spacing and alignment considerations
Correct spacing ensures the interlock plate aligns with screw holes and maintains safe separation of live components. Some kits demand 1 3/8″ spacing, others 1 1/4″ or up to 3 1/4″ to 4″. Follow the included installation notes and, if possible, perform a dry fit before final mounting.
Safety and installation guidance
Choose kits that clearly state prevention of simultaneous mains and generator power. The interlock should direct generator power to a defined subset of circuits while the mains are isolated. If you are not experienced with electrical work, consider professional installation to reduce risk of improper hookup.
What about installation hardware and documentation?
Look for kits that include screws, drill bits, labels, and an installation bulletin. Adequate documentation helps align the interlock correctly and provides start-up procedures for safe operation during outages.
Usage scenarios: when to choose an interlock
Consider an interlock if you want a code-compliant, non-backfed generator setup that isolates the main feed and allows controlled power distribution. For households with frequent outages or off-grid needs, ensure the kit’s amperage and panel compatibility match your backup plan.
Plan for future upgrades
If you plan to upgrade panel capacity or switch brands, verify whether the chosen interlock remains compatible or if a different kit is required for future installations.
Frequently Asked Questions
- What is the primary purpose of a generator interlock kit? It prevents simultaneous main and generator power, while safely routing generator power to designated circuits during an outage.
- How do I know which interlock kit fits my panel? Check your panel brand, model, and amperage, then match the kit’s compatibility and required spacing to those specifications.
- Is professional installation recommended? Yes, especially if you are not experienced with electrical work, to ensure safe and code-compliant operation.
- Can I mix interlock kits with different panel types in my home? It is best to use a kit designed for each panel type and amperage, to avoid improper fit or unsafe configurations.
- What spacing should I expect for common kits? Spacing varies: 7/8″–1 1/4″ for some Siemens/Murray kits, 1 3/8″ for Square D options, and 1 1/4″–1 7/16″ for Eaton BR kits.
- Do interlock kits affect warranty or code compliance? When installed correctly and used as intended, they support safe operation and align with common electrical code practices; verify local codes.