Pump GFCI keeps tripping

[dmax724]

- Over the last 3 weeks, GFCI breaker has tripped 3 times (yesterday was during a dry/calm day while pump running at only 1400 rpm - a couple days after I siliconed around the junction box thinking maybe moisture was getting in box during rain...to rule that out).

- 4 weeks ago installed a new Pentair variable speed pool pump #342001 (that auto senses voltage to run on 120 or 240).
- Running on a new GFCI 120v/20amp breaker (pump has max 13.3A on 120 so not a max amperage thing).
- Also on a new dedicated 70' 12/3 copper circuit (only using the 2 conductors now, but wanted to have option in future to easily go to 240v. I also ran electrical calculator for 70' run and 12/3 copper is in spec).
- Also on a new well protected junction box with no signs of moisture.
- Good new liquid tight conduit connections from box to pump.


Looking for logical next step...
Should I try a different brand breaker?
Any idea if less likely if switching to a 240 circuit/GFCI breaker make it less likely to happen? (I assume breaker have same sensitivity and was hoping to avoid that with the added cost of 240 GFCI breaker).
Any other ideas to troubleshoot/isolate?

 

[danpik]

there is a breaker that works good with that pump. I don't recall the brand off the top of my head. maybe one of the other guys remembers it. That pump has issues on GFCI's that causes it to trip

 

[dmax724]

Here is what Pentair had to say....to then recommend their brand breaker which unfortunately only comes in Siemens type (and my panel is CH type):
"Variable Speed pumps will commonly do this with standard GFCI breakers. You will need to switch the breaker out with one that has a minimum of a 6 milliamp GFCI rating, this will solve the issue."
I am now leaning towards converting it to 240v GFCI to see if that changes the dynamics with lower amperage involved.

 

[danpik]

Yep, Siemens is the one. I doubt changing to a 240 will solve the problem. This is a voltage issue not an amperage issue. The VFD in the pump is tricking the GFCI into thinking there is a voltage leak when it alters the frequency that the motor runs at.

Dan

 

[gwegan]

I'm going to agree with Dan here. This is the reason they like the Siemens breaker. It sounds like you are running this direct from you main house panel. Do you have a maintenance disconnect? Not a switch, a disconect within sight of the pump and not more than 50 feet away.

I would see replace you 20 amp GFCI breaker with a regular breaker. Then get a Seamens sub panel and 20 amp GFCI breaker and set it up next to the pump as a disconnect.

 

[CJadamec]

I have the same pump and installed a Seimens GFCI breaker and haven't had an issue yet. Use the breaker for personal protection (class A) which is 5mA. That is what is required to protect you and your kids. DO NOT use the 20mA gfci breakers rated for equipment protection only. The breaker you are looking for is Siemens-QF120 (the 220v version is QF-220). I also prefer gwegan's suggestion of adding the subpanel and putting the breaker outside, but if you are using a twist lock plug on your pump that does count as a service disconnect.