rshackleford said:
found this in the FE Manual:
When an installation has abnormally corrosive water
AND the drop pipe or casing is plastic, Franklin Electric
recommends the use of a GFCI with a 10 mA set-point.
In this case, the motor ground wire should be routed
through the current-sensing device along with the motor
power leads. Wired this way, the GFCI will trip only when
a ground fault has occurred AND the motor ground wire
is no longer functional.
In other words, you hope that when there is a ground fault the fault current will travel through the ground wire and the GFCI to account for the difference in current in the hot conductors, and thereby prevent the ground fault from tripping the GFCI.
Three things to consider.
1. If it works, it defeats the function of the GFCI.
2. In many wells the casing doesn't go all the way to the aquifer and some of the fault current may find its way to ground via the aquifer.
3. It is not unusual for there to be a few volts between the neutral as measured at the panel, and the EARTH some distance away. Such a potential could cause more than 10 mA of current in the ground wire and cause the GFCI to trip EVEN IF THERE IS NO GROUND FAULT IN THE MOTOR.
The last condition could be causing the breaker to trip EVEN IF you have a good motor.
You might check for the last condition by removing the ground wire from the GFCI and checking for voltage (even a few millivolts) between the ground wire and the neutral bar where the white wire from the GFCI is connected. Check it with the motor power on and with the motor power off.