New pump trips 60 amp GFCI when under load

[mising]

Good Morning!

I just replaced my 3hp 230v pump motor, and it runs great until it starts to build pressure then it trips the main 60 amp breaker for the pool breaker box.
It is the same model motor (Century Centurion B818/ST1302V1) that was previously installed, so I plugged the wires into the same terminals as before: Black 1 (118v) to L1, Black 2 (118v) to L2, and Green to the "A" terminal.
While looking up information on troubleshooting, most sites say that the Green wire should be connected to the ground screw and do not mention the "A" terminal?

I also noticed that the wires going into the 60 amp breaker are a bit corroded and improperly stripped, so I am thinking that is where I should start.
Unfortunately, that breaker comes directly out of the meter box, so I will have to wait until our utility company can shut off the power.

 

[drsipe]

If the 60 amp GFCI breaker, which is feeding your pool equipment sub panel is tripping, It's probably not tripping on amperage, it's probably tripping via the GFCI. If the pump was drawing too many amps the equipment breaker would trip, before the feeder breaker would trip.

Since you mentioned that you just changed the pump motor, I would start there. Look for any bare wire in contact with the motor frame. A GFCI works by looking for a balance in electrical flow, if the GFCI sees unbalanced electrical flow, the assumption is that voltage is leaking somewhere you don't want it and the GFCI trips.

With the equipment breaker open, use a multi meter to check continuity between each phase (hot) and ground or motor frame. There should not be any continuity.

 

[laprjns]

In the equipment breaker box both bus bars, one on the left and the other on the right, appear to be used for the neutral connections. If the heavy black wire that is connected to that bus bar on the right is the neutral line coming from the 60 amp GFCI breaker then the green wire, assuming that it is an equipment ground wire, should not be connected there. Neutrals and equipment ground wire should not be connected at a subpanel. I cannot see from the pictures where the equipment ground wires are connected in the equipment breaker box.

 

[mising]

If the 60 amp GFCI breaker, which is feeding your pool equipment sub panel is tripping, It's probably not tripping on amperage, it's probably tripping via the GFCI. If the pump was drawing too many amps the equipment breaker would trip, before the feeder breaker would trip.

Since you mentioned that you just changed the pump motor, I would start there. Look for any bare wire in contact with the motor frame. A GFCI works by looking for a balance in electrical flow, if the GFCI sees unbalanced electrical flow, the assumption is that voltage is leaking somewhere you don't want it and the GFCI trips.

With the equipment breaker open, use a multi meter to check continuity between each phase (hot) and ground or motor frame. There should not be any continuity.

Yep, there is continuity between both the L1 and ground and L2 and ground, so I guess that I have a faulty motor or at least a bad circuit board.

 

[mising]

In the equipment breaker box both bus bars, one on the left and the other on the right, appear to be used for the neutral connections. If the heavy black wire that is connected to that bus bar on the right is the neutral line coming from the 60 amp GFCI breaker then the green wire, assuming that it is an equipment ground wire, should not be connected there. Neutrals and equipment ground wire should not be connected at a subpanel. I cannot see from the pictures where the equipment ground wires are connected in the equipment breaker box.

I traced the black wire on the bus on the right and it does go to the neutral on the 60 amp breaker. We have lived here for about 15 years and this is the first time I've had that panel open, but the company that the previous owners told us installed the pool went out of business about 10 years ago. There are also no grounds/bonds between the equipment like I thought there should be either, so who knows how they set all of this up.

 

[laprjns]

Yep, there is continuity between both the L1 and ground and L2 and ground, so I guess that I have a faulty motor or at least a bad circuit board.

Disconnect that green wire from the right side bus bar and then remeasure L1 and L2 to ground. Also, where do those green wires at the bottom of the equipment breaker box go to?

I traced the black wire on the bus on the right and it does go to the neutral on the 60 amp breaker. We have lived here for about 15 years and this is the first time I've had that panel open, but the company that the previous owners told us installed the pool went out of business about 10 years ago. There are also no grounds/bonds between the equipment like I thought there should be either, so who knows how they set all of this up.

You might want to get an electrician out to look at it.

 

[drsipe]

Yep, there is continuity between both the L1 and ground and L2 and ground, so I guess that I have a faulty motor or at least a bad circuit board.

Not necessarily, it just points to the reason the GFCI is tripping.

Now you need to investigate. You can unwire the motor and perform the same continuity test on the bare wires, then on the disconnected motor. That will help you work in the right direction.

I have a dumb question. On the old motor, was the ground connected?

 

[laprjns]

It is the same model motor (Century Centurion B818/ST1302V1) that was previously installed, so I plugged the wires into the same terminals as before: Black 1 (118v) to L1, Black 2 (118v) to L2, and Green to the "A" terminal.
While looking up information on troubleshooting, most sites say that the Green wire should be connected to the ground screw and do not mention the "A" terminal?

Are you referring to the Timing Box here? If so, then the green wire from the motor should be connected to the green ground screw and not the "A" terminal. From the picture that you posted, it looks like the "A" terminal has white wires (assuming neutral lines) attached.

 

[mising]

Thanks for all of the suggestions and tips.
Due to the continuity between all of the terminals and ground I decided to go ahead and disassemble the motor. I tried contacting Century first, but they said I would have to take it to a authorized distributor and since the closest one was over an hour and a half away, I took the gamble to take a peek myself especially since there were no temper stickers on the motor.
It looks like during assembly, the wire feeding L2 was pinched in between the end cap and housing. I was able to put some shrink tubing over it and make sure that it was tucked in much better. It has been running like a champ all weekend.
I am still getting the utility company to do a temporary disconnect so that I can take care of the crappy wire termination on the 60 amp main breaker though.

Thanks again!

 

[drsipe]

I'm glad we were able to give you some ideas so that you could find and repair the problem.

 

[sktn77a]

I'd contact Century and let them know you weren't impressed with their crappy (and potentially dangerous) assembly techniques!

 

[CountryBoy19]

I'd contact Century and let them know you weren't impressed with their crappy (and potentially dangerous) assembly techniques!

Things happen...it should be caught in the quality control process but no process is perfect.

I have a somewhat related story. When I wired my shop (all surface mount EMT conduit) I had already moved some of my equipment in (several thousand pounds and not moving it to do electrical). I had temporarily hooked up power from an OLD abandoned adjacent structure just so I could have working lights and HVAC while working. I was feeding the main panel with a long cord so as I finished a circuit I could bring it on-line. I hadn't yet done the proper ground for the panel because I was basically running as a sub-panel with ground & neutral unbounded. The EMT was/is my ground path. At one point every time I touched the EMT or a box with sweaty hands I got a tickle. I discovered A) there was a fault in the ground of the old structure, and B) I was getting leakage onto my improperly grounded ground path which was tickling me. There was 1 box that was particularly difficult to wire up due to very little clearance and I eventually discovered I had inadvertently pinched a hot when putting the cover on that box.

 

[Mike1162]

It may just be the picture but the left wire on terminal #4 of the timer looks iffy.