10 Best Overload Relays

Review Analysis Conclusion

Based on analysis of 4,667 reviews, the ranking reflects a clear split between two use cases. The top four slots are dominated by Schneider Electric thermal overload relays with strong but narrower review bases (15–53 reviews each), prized by industrial buyers for precise trip curves, TeSys family compatibility, and screw-clamp termination. Below them, refrigerator PTC starter and overload protector kits from Mudder, QP, and Wehhbtye command the bulk of review volume—thousands of verified service-call reports that confirm fitment for LG, Whirlpool, Danby, and similar compressors. Mid-ranking entries such as the Baomain SP30 contactor combo show lower review counts but earn credit for integrated, panel-ready design. Confidence is highest where review depth, brand documentation, and recent purchase velocity align, and lower for two-review SKUs where long-term reliability is harder to confirm.

Buying Guide

Overload relays are the quiet first line of defense for electric motors and hermetic compressors. When current draw exceeds safe thermal limits, the relay opens the circuit before insulation degrades, windings scorch, or a fire risk develops. Choosing the best overload relay is less about chasing the highest amp rating and more about matching current window, trip class, reset mode, and termination to the actual load.

Quick Picks at a Glance

• Best for fractional to mid-HP motors (HVAC, pumps, fans): 16–24 A TeSys or Easy TeSys thermal overload relay, manual/auto reset, screw-clamp terminals.
• Best for larger commercial compressors and three-phase loads: 23–32 A Easy TeSys relay paired with the matching Schneider contactor.
• Best for refrigerator and freezer compressor repair: Matched PTC starter and overload protector kit, with pin count and ohm rating matched to the OEM compressor.
• Best for fleet or multi-unit service: Bulk four-pack kits that lower per-unit cost and keep spares clean on the truck.
• Best for turnkey panel builds: Combined contactor and overload relay assembly with auxiliary contacts for interlocking.

Sizing and Current Capacity

Start with the full-load amperage (FLA) on the motor nameplate. Thermal overload relays are adjustable across a defined window—common bands include 7–10 A, 16–24 A, and 23–32 A—and the motor’s FLA should sit comfortably inside that band rather than at the extreme ends. If FLA is near the top of one range, step up; if it is near the bottom, step down. Finer calibration produces faster, more predictable trip response.

For industrial motors, pay attention to trip class. Class 20 is standard for general-purpose motors and tolerates a brief inrush; Class 10 trips faster and suits low-inertia or winding-sensitive loads. Refrigerator and mini-fridge compressors use a different topology: a PTC starter relay paired with a separate overload protector. These are not dial-adjustable—match the ohm rating (commonly 4.7 ohms) and pin count to the compressor’s start winding specifications.

Feature Tradeoffs

Industrial thermal relays vary mainly in reset behavior and termination:

• Manual reset keeps a tripped unit offline until a technician intervenes, ideal for unattended pumps, conveyors, or remote sites where auto-restart could cause damage or injury.
• Automatic reset restores service once the bimetallic strip cools, useful for HVAC equipment in occupied spaces where short downtime is acceptable.
• Screw-clamp terminals accept ring or fork lugs and resist loosening under vibration; preferred for industrial cabinets and motor control centers.
• Push-in or spring terminals speed wiring but may need periodic re-torque checks in high-vibration environments.

For refrigerator PTC kits, the primary tradeoff is pin count. One-pin designs suit LG and Kenmore-style compressors; three-pin variants fit a broader range of mini fridges, wine coolers, and chest freezers.

Best For / Avoid If

• Best for: panel builders maintaining TeSys contactor fleets, HVAC technicians needing 16–24 A or 23–32 A coverage, appliance repair services handling frequent compressor swap-outs, and property managers stocking spare PTC pairs.
• Avoid if: the motor’s FLA falls outside the relay’s adjustment window, the compressor uses a non-matching pin configuration, or the application requires SIL-rated safety functions—standard thermal overload relays are not safety devices.

Key Specifications to Compare

Installation and Setup Considerations

Confirm physical compatibility before energizing. Industrial relays mount beneath or beside a magnetic contactor; the relay’s heater elements sense load current passing through the power path. Verify line/load orientation, leave clearance for reset access and airflow, and de-energize both control and power circuits before wiring. After installation, dial the current setting to the motor’s FLA and run a no-load check to confirm direction and current draw.

For compressor repair, photograph the original terminal layout before removal—pin orientation is not always obvious on hermetic terminals. If the existing overload protector is loose, discolored, or shows burn marks, replace the relay and protector together; pairing a fresh PTC starter with a fatigued overload invites repeat failures.

Common Mistakes

• Sizing to horsepower alone instead of nameplate FLA.
• Setting the dial at the very top or bottom of the adjustment range.
• Mixing a new PTC starter with an old overload protector.
• Choosing three-pin kits for one-pin compressors (or vice versa).
• Ignoring voltage imbalance, which causes nuisance tripping on three-phase systems.
• Skipping annual torque checks on screw-clamp terminals in vibrating panels.

Maintenance and Reliability Signals

Industrial relays need little routine service, but annual inspection pays off. Check screw-clamp torque, clear dust that can insulate the bimetallic element and skew trip points, and log any nuisance trips. Repeated tripping without a clear motor fault often points to bearing wear, voltage imbalance, or an undersized supply conductor rather than a defective relay.

For appliance kits, longevity shows up in review patterns. Products with hundreds or thousands of reports describing successful compressor restarts after years of dormancy indicate consistent manufacturing tolerances. Listings with very thin feedback or recurring fitment complaints deserve caution, since compressor terminal boxes vary slightly by OEM and a small pin offset can cause arcing.

How to Compare Reviews

Separate installation errors from genuine product defects. Comments like “trips immediately” on an industrial relay often trace to incorrect heater sizing rather than a faulty unit. Look for longevity notes—months or years of service, surviving peak loads, or repeat technician use. For appliance kits, prioritize reviews that name specific compressor brands and model numbers; generic praise is weaker evidence than a confirmed match to your LG, Whirlpool, or Danby unit.

FAQ

Do overload relays replace circuit breakers? No. Breakers protect wiring from short circuits; overload relays protect motors from sustained overcurrent. Most motor circuits use both.

Can I use an automatic reset relay on a pump? It depends on the application. Unattended pumps that could run dry benefit from manual reset so a technician can investigate before restart.

Why does a new refrigerator keep tripping its overload? Common causes include a weak start capacitor, high head pressure from a blocked condenser, or a failing compressor drawing locked-rotor current. Replacing the relay without diagnosing the root cause usually leads to another failure.

Are thermal and electronic overload relays interchangeable? Not directly. Electronic relays offer adjustable trip classes and communication features but require compatible contactors and wiring diagrams.

Final Recommendation

For commercial motors, pumps, or HVAC compressors, choose a Schneider Electric TeSys or Easy TeSys thermal overload relay whose current range comfortably brackets your motor’s FLA. The manual/auto reset flexibility and screw-clamp terminals in the top-ranked industrial models offer a strong balance of safety and serviceability. Stocking both a 16–24 A and a 23–32 A variant covers most fractional to mid-horsepower loads a maintenance team will encounter.

For refrigerator or freezer repair, select a PTC starter and overload protector kit that matches your compressor’s pin count and ohm rating. The highest-scored appliance kits pair strong review volume with high recent purchase velocity, signaling technician trust on repeat service calls. When in doubt, replace both halves of the start circuit together.

The best overload relay is the one that fits precisely, trips at the right current, and resets in a way that matches how the equipment is actually operated. Use the ranked list to narrow the field, then confirm motor or compressor specifications before ordering.