GFCI Trips Randomly

[JBHorne]

We installed a new Pentair EZTouch subpanel with an Intelliflo 2 vst pump and two Whisperflow pumps for the spa jets and waterfall. I put each pump on a separate GFCI. The first few weeks, everything was fine without issue. Being that this is a subpanel, I wanted to follow code and drove two 8ft grounding rods into the ground, connected to the ground bus. Ever since then, every few days my GFCIs trip. It's usually the filter pump (inelliflo) that trips, but someones all three trip. I can't isolate this to anything specific. It has not rained and the pool pad is far away from the water and/or any sprinklers.

What would cause a GFCI to trip on a new build? Does it make any sense that all three would trip? I don't see how as the load side is different for each. Is it possible the issue is with the feeder wires -- I didn't think GFCI's check/trip from the line side? The feeder wires are new, but the underground conduit was reused. Also, strange this is an intermittent issue. It does not occur while the pump is running, but typically overnight I get an email from ScreenLogic that it lost communication to the pump (this is how I know to go outside to check the breakers).

Any guidance/thoughts are greatly appreciated!

Thanks!
Justin

 

[Jimrahbe]

JB,

I was under the impression that only the main panel got a grounding rod, but I'm not really sure one way or the other. What told you to add the grounding rods?

Pentair has a specific GFCI breaker for the Intelliflo. They produced it because the Intelliflo, in some cases, will trip a standard GFCI.

Jim R.

 

[JBHorne]

JB,

I was under the impression that only the main panel got a grounding rod, but I'm not really sure one way or the other. What told you to add the grounding rods?

Pentair has a specific GFCI breaker for the Intelliflo. They produced it because the Intelliflo, in some cases, will trip a standard GFCI.

Jim R.

The grounding rods are required per NEC code for subpanel installation. This is considered a subpanel, not a Multiwire Branch Circuit (MWBC) because it uses a single feeder line to power multiple breakers. I have no clue why Pentair doesn't inform users of this in the manual, and most pool "electricians" have no clue. But it's treated as a detached subpanel per NEC. I spent a lot of time going around and about this, but code is code

As for Pentair's special GFCI's, I didn't realize they were any different. I got the Siemens QF220 20-Amp 2 Pole GFCIs. They weren't cheap at $80/each.

What's strange here is when ALL the GFCIs are tripping at once. That I can't explain, unless there is a feeder wire issue, voltage coming back through the grounding rods, etc. And then why it only happens overnight and not all the time.

 

[Jimrahbe]

JB,

Weird, I've seen several different pool subpanels and have never seen a ground rod connection. It could be that the pool bonding system takes the place of the ground rods.

We have got a couple of pretty good electrical guys here, so maybe one of them will chime in.

Personally, I'd disconnect the ground rods and let it run for a while to confirm if they are the actual cause of the issue or not.

Jim R.

 

[gwegan]

Is this a separate structure? What NEC section do you believe requires you to install a ground rod? Unless there is a specific reason generally ground rods and pools do not get along. The NEC allows you to install a ground rod just about anywhere but generally only requires then for separate structures and a pool does not count.


You need to be sure that your subpanel has a floating neutral buss bar and the ground wires are insulated and run to the main panel's neutral buss bar. The neutral and ground buss bars should not be connected in the subpanel. That might be causing the problem.

What is the manufacturer of the breakers? Pentair VSPs can be very particular with what breakers they like. Pentair sells its own breakers manufactured by Siemans. This is a common problem.

 

[Jimrahbe]

gwegan,

I appreciate your input.

Thanks,

Jim R.

 

[JBHorne]

Is this a separate structure? What NEC section do you believe requires you to install a ground rod? Unless there is a specific reason generally ground rods and pools do not get along. The NEC allows you to install a ground rod just about anywhere but generally only requires then for separate structures and a pool does not count.

I guess I don't see where a pool is not considered a "separate structure". NEC 250.32 and 250.50 require that all subpanels installed in "separate structures" (meaning not attached to the primary structure) have separate grounding rods. My panel is installed on an exterior wall not connected to the house. The NEC doesn't explicitly define "separate structure", only that a "structure" is "that which is built or constructed". So, one can surmise that since a pool is "constructed" and the panel is "separate" from the house, than 250.32/50 apply.

Outside of "code", is it even possible to have too much ground? Would that trip a GFCI?

You need to be sure that your subpanel has a floating neutral buss bar and the ground wires are insulated and run to the main panel's neutral buss bar. The neutral and ground buss bars should not be connected in the subpanel. That might be causing the problem.

The neutral buss bar is floating and I do have an insulated ground running back to the main panel. The neutral and ground are only connected at the main panel.

What is the manufacturer of the breakers? Pentair VSPs can be very particular with what breakers they like. Pentair sells its own breakers manufactured by Siemans. This is a common problem.

Siemens QF220 20-Amp 2 Pole GFCIs. Keep in mind I have three pumps each on a separate GFCI and when they trip, they ALL trip simultaneously.


I appreciate the help!