roy g

[roy g]

working on replacing in ground residential pool pump, 230 volt, GFCi protected, 1 HP. Existing pump had been in service for approx. 20 years and was operational (except for bad bearings)
The existing pump was bonded through the branch circuit conductor and customer says no problem over the years. I installed a 5/8 x 8 ground rod, reconnected new pump. Pump will work fine until the # 8 bond wire from the pump is connected to the rod which than trips breaker. Resistance reading from branch circuit egc and from # 8 wire ground to new pump to ground rod is 1500 ohms. and infinity reading from power conductors in branch circuit as well as wiring going to pump and branch circuit EGC. What am I not seeing that is causing the GFCI to trip?

 

[petersonra]

Just out of curiosity, why did you add a ground rod?

 

[charlie b]

To that I will add, what are you connecting the ground rod to (i.e., where do you connect the other end of the #8 wire), just before it trips the breaker?

 

[luckylerado]

Did you measure anything from the motor leads to the motor bonding connection?

 

[roy g]

roy g

To that I will add, what are you connecting the ground rod to (i.e., where do you connect the other end of the #8 wire), just before it trips the breaker?

the ground lug is exterior on the the motor frame, which is tripping the breaker when attached to the ground rod. the EGC for the branch circuit is connected inside the terminal box on the grounding screw . Thanks for the reply

 

[roy g]

roy g

Did you measure anything from the motor leads to the motor bonding connection?

thanks for reply, I get infinity reading from all power conductors (both branch circuit and motor leads) to ground.

 

[luckylerado]

thanks for reply, I get infinity reading from all power conductors (both branch circuit and motor leads) to ground.

I don't suppose you have a megger handy?

What is landed on the N side of the GFI breaker? The EGC?

 

[roy g]

roy g

Just out of curiosity, why did you add a ground rod?

it has been my understanding that a ground rod is required. This is a permantly installed pump (not cord connected), with the BC coming from the residence service to the disconnect switch for the motor. Although this pump didn't specifically indicate to drive a separate rod, I have seen other pool pumps and pool heaters that the manufacture instructions require a driven ground rod. Thanks for the help

 

[roy g]

roy g

I don't suppose you have a megger handy?

What is landed on the N side of the GFI breaker? The EGC?

the branch circuit is type 12-2 uf cable (bare conductor for ground) which is landed on the breaker neutral. What puzzles me is what does connecting the ground rod into the circuit cause it to trip? Thanks

 

[luckylerado]

I would bet if you megged the motor leads to the bonding lug that you would see less than infinity ohms. A small in-balance between A and B will trip the GFI part of the breaker without seeing the load back on the N side. I would expect that you could hook it up via a regular breaker and it would hold. Then use a clamp on ampmeter to measure each phase. I bet you get a slightly different Amp reading between A and B. I am in no way suggesting that you remove the GFI protection other than to test the theory.

 

[roy g]

roy g

I would bet if you megged the motor leads to the bonding lug that you would see less than infinity ohms. A small in-balance between A and B will trip the GFI part of the breaker without seeing the load back on the N side. I would expect that you could hook it up via a regular breaker and it would hold. Then use a clamp on ampmeter to measure each phase. I bet you get a slightly different Amp reading between A and B. I am in no way suggesting that you remove the GFI protection other than to test the theory.

I will try that tomorrow. I still do not understand why the gfci works as usual with out tripping until the rod connection is made. thanks for suggestion

 

[Dennis Alwon]

I would disconnect the ground rod. It is not needed. You may be picking up some stray voltage from the earth that is causing this issue.

 

[roy g]

roy g

Thanks dennis, that was a thought. its something odd that it has worked for years without tripping and continues until connection is made to rod. I would rather error on the side of safety, but over the years seen some odd things happen with stray voltage.

 

[mopowr steve]

the branch circuit is type 12-2 uf cable (bare conductor for ground) which is landed on the breaker neutral. What puzzles me is what does connecting the ground rod into the circuit cause it to trip? Thanks

I think your answer is right in front of you.
Why is the bare ground being used as a neutral to pool panel? And did you happen to attach your ground from pool pump to the load side neutral connection on GFCI breaker? If so the GFCI breaker is sensing an alternate path for neutral current through ground rod connection back to source.

The lug on the motor frame is for connection to equipotential bonding grid around pool.

Sounds like you need a neutral ran from house panel to pool panel for the connection of GFCI breaker neutral. Which I believe may need to be connected regardless if there is a need for load neutral connection from GFCI breaker to pool equipment. At least you may need a 2pole GFCI breaker that does not have neutral connection at all, since pool pump is strictly 230v and you have NO neutral loads.

 

[sparkyrick]

I think your answer is right in front of you.
Why is the bare ground being used as a neutral to pool panel? And did you happen to attach your ground from pool pump to the load side neutral connection on GFCI breaker? If so the GFCI breaker is sensing an alternate path for neutral current through ground rod connection back to source.

The lug on the motor frame is for connection to equipotential bonding grid around pool.

Sounds like you need a neutral ran from house panel to pool panel for the connection of GFCI breaker neutral. Which I believe may need to be connected regardless if there is a need for load neutral connection from GFCI breaker to pool equipment. At least you may need a 2pole GFCI breaker that does not have neutral connection at all, since pool pump is strictly 230v and you have NO neutral loads.

Remove the ground from the neutral of the GFCI breaker and move it to the ground bar in the panel. That's your problem right there. Like Mopowr said, the lug on the motor is for the #8 solid bonding all the metal parts of the pool together. The GFCI with the neutral can stay, it'll work without a load connection to the neutral.

That said, if the pump equipment DOES require a neutral, you'll have to get a neutral out to the pump equipment and connect it to the GFCI breaker.

 

[George Stolz]

You may be picking up some stray voltage from the earth that is causing this issue.

That is inconceivable. Stray voltage doesn't work that way.

 

[luckylerado]

The fact that is has worked for years does not mean that there was not always a problem. The GFI should not trip unless an alternate path has been created and some current is flowing out but not making a round trip. It sounds to me that the ground rod has provided enough difference of potential to reveal a fault to ground. Probably in the winding but could be in the terminal housing or cable. Until now the fault has been "seen" by the breaker as normal neutral current since the grounding wire has been miswired to the N side of the breaker and there is too much resistance to blow the OCP because we are probably only talking in terms of mA

Assume that the GFI breaker is doing its job. This should highlight the need for proper equipotential grounding.

Have you tried to turn on the pump and then measure voltage between the housing grounding terminal and the rod while the pump is running.

 

[qcroanoke]

Remove the ground from the neutral of the GFCI breaker and move it to the ground bar in the panel. That's your problem right there. Like Mopowr said, the lug on the motor is for the #8 solid bonding all the metal parts of the pool together. The GFCI with the neutral can stay, it'll work without a load connection to the neutral.

That said, if the pump equipment DOES require a neutral, you'll have to get a neutral out to the pump equipment and connect it to the GFCI breaker.

I agree.

 

[Rayl82]

Power is always going to take the fastest thought to ground. That's why if you insulate yourself from ground properly you can tuch individual live conductors with no repercussions.... The case ground and ground to windings are generally the same and by adding the ground rod you've effectively created a shorter path to ground. And the breaker doesn't see it so it trips as if there were a problem.

Sent from my HTC One M9 using Tapatalk

 

[George Stolz]

Power is always going to take the fastest thought to ground. That's why if you insulate yourself from ground properly you can tuch individual live conductors with no repercussions.... The case ground and ground to windings are generally the same and by adding the ground rod you've effectively created a shorter path to ground. And the breaker doesn't see it so it trips as if there were a problem.

Sent from my HTC One M9 using Tapatalk

Ray, please see this post. Welcome to the forum.