Pool Bonding

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inspector 102

Senior Member
Location
Northern Indiana
Situation as follows: 24 foot diameter aboveground pool. 100' from house, fed with #10 THHN insulated in nonmettalic conduit to allow for voltage drop. 1 HP pump with bonding lug plug into GFCI receptacle. The bonding is completed by a #4 wire from bonding lug on pump to ground rod driven and then to metal supports of pool.
Problem - When the bonding wire is connected, the water surface becomes energized. When the bond is removed from the pump, no problem.
The pool is not in my jurisdiction, but I was asked to review the situation. The only problem I saw was the stranded bond wire in lieu of solid. What could be casuing the electrical charge through the bond lug other the motor malfunction. The voltage tested from the lug to the ground rod ranged from 2 volts to as high a 26 volts. Any thoughts?
 
Does the GFCI trip?
Ground rod for pool is not needed. What happens if this rod is left out of the "loop". First thought is that the motor is bad, but the GFCI should be tripping if current is returning to source through the earth or grounding conductor. Is the grounding conductor (not the bonding conductor) properly connected to the motor? Need to determine if the voltage you are reading from the ground rod to the motor is originating at the motor, or if it is stray voltage which is coming from the earth to the ground rod and using the motor as a return.
 
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The GFCI is not tripping. The voltage reading is between the ground rod and the bonding lug on the motor and the motor casing. It would appear to me that the insulation of the motor might have a failure causing the leakage. Told homeowner to contact all parties involved with installation to get everyone working toward correcting potential issues. Still waiting to hear back on what pump manufacterer said.
 
If you have a bad winding, it should be tripping the circuit breaker, either through a short or over-amps. Check the connector where the branch circuit comes in that it is not pinched. Also, when you remove the bond you should still have your stray voltage somewhere.
 
Inspector,
The voltage reading is between the ground rod and the bonding lug on the motor and the motor casing.
I assume that this is with the bonding conductor between the rod and the motor disconnected. I would look at a neutral problem with the service to the building.
Don
 
Do you still read voltage with the main breaker in the house switched off?

I'm willing to bet that you do.

IF SO, then the problem is not in your permises wiring system, nor the motor, nor any GFI devices.

You will have to get the power company involved, and possibly the neighbors, etc.

One final note: The less moist your ground is (eg: lack of recent rain), the greater this problem will manifest itself.
 
The 2005 NEC Handbook states in Article 680.21(B) commentary that cord and plug connected double insulated swimming pool pumps are not required to be incorporatewd into the bonding system, since the act of bonding compromises the double-insulation system. Can someone explain, in simple language, how that occurs.
 
inspector 102 said:
The 2005 NEC Handbook states in Article 680.21(B) commentary that cord and plug connected double insulated swimming pool pumps are not required to be incorporatewd into the bonding system, since the act of bonding compromises the double-insulation system. Can someone explain, in simple language, how that occurs.
The double insulated motor/pumps have no exposed metallic parts. If you somehow managed to bond a double insulated motor/pump, you'd really have hacked it up.
 
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