If your GFCI breaker is tripping,then first of all you will have to insure whether your GFCI breaker always trips immediately or not.If your GFCI breaker always trips immediately then may be there is a ground fault condition,for this condition you will have to check it out your cable,connectors and motor for water penetration.If you found a leakage in the cord then this leak in the cord may be caused from cuts by rodents chewing on the cable,sharp rocks,something hitting the cord etc.Or from a leak at the quick disconnect or where the cord connects to the unit.Visually check the cord for any knicks or cuts and also look at the quick disconnect for any water contamination.(Note: water may be in the threads of the disconnect without causing damage).If there is a Motor Contamination then due to this over time the seals in the motor will wear out.This may cause a slight bit of water to contaminate the motor and oil and cause the breaker to trip.If none of the other items above seem to be the problem,the motor should checked by an Authorized repair center.If the breaker only trips when the lights try to turn on,it may indicate that no neutral wire was supplied to the control panel or the neutral wire is faulty.Make sure the neutral is supplied and is proper and sufficient.
If that water penetration is not a cause then may be your GFCI breaker is faulty.For this fault check you should have to perform the manual test on the breaker to see if it is functioning properly.If GFCI breakers are tripped many times,they tend to increase in sensitivity(or may not trip at all)and can need replacement.
Now we need to go back on the very first step where we have insured that our GFCI breaker always trips immediately.The all above explanation is for that condition when you have insured that yes my breaker always trips immediately.Now what if your GFCI breaker not always trips immediately.Okay let us move for further possibilities on this condition.
Next step is to insure whether your breaker trips randomly,if yes then it indicates Nuisance tripping.
The causes for Nuisance Tripping are Supply voltage and Unbalanced or Intermitant Loads.
1. Supply Voltage :
If there is a problem of supply voltage,it may occurs due to variations in supply voltage,long distance between control panel and main power at property,induced current into the neutral wire or Soil ph levels.
A local ground stake at the control panel usually eliminates this problem.Also,distances over 250′ on the load side of the GFCI breaker can cause nuisance tripping.
2. Unbalanced,Intermitant Loads :
If the cause of this nuisance tripping is Unbalanced or Intermitant Loads then on 240v units,check for unbalanced loads on the power line.These unbalanced loads(refrigerators,Air conditioners,etc)switching on and and off can cause the GFCI breaker to trip randomly.
If your GFCI breaker not trips randomly then may be your breaker is tripping on overcurrent.And the cause of this overcurrent is High Amps.
High Amps :
If a unit is under greater than normal load due to clogging or a faulty motor,the amp draw could rise and cause the breaker to trip.If nothing is clogging the unit and the amp draw is too high,it needs to be looked at by an Authorized repair center.