Kubota Nuisance Breaker Tripping on Motor Start

Kubota generator runs but frequently trips its main breaker when large motors or compressors start.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Motor inrush current too high for generator size, Weak or aged breaker, Loose connections causing heat, Incorrect breaker rating

How to Fix / Troubleshooting

Safety first: De-energize circuits before opening panels. Only qualified personnel should work on load-side wiring.

  • Measure inrush current: Use a clamp meter with inrush function to measure starting current of problem loads. Compare to generator and breaker ratings.
  • Check breaker rating: Confirm the main breaker amp rating matches the generator's nameplate output and Kubota specifications.
  • Inspect breaker and lugs: Look for discoloration or heat damage at breaker terminals. Tighten lugs to specified torque.
  • Soft start options: Consider installing soft starters or VFDs on large motors to reduce inrush current.
  • Replace breaker: If the breaker trips below its rated current or shows signs of wear, replace it with an OEM-specified unit.
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Repair Difficulty

Hard 4/5

Required Part

Main Circuit Breaker
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