7.5 hp 230 volt trips 60 amp GFCI breaker

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stephenweyant

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hello
I am having issues with gfci breakers tripping when installed on 7.5 hp single phase pump motors. if im not mistaken, all single phase swimming pool pump circuits regardless of voltage or amperage must be GFCI protected. so when we are faced with a 7.5 hp single phase, 230 volt pump, we are installing a 60 amp, 2 pole GFCI breaker. wiring is simple enough, two ungrounded conductors on breaker go to motor, no load neutral, and pig tail neutral from breaker goes to neutral bar of panel. upon start up, 3 out 3 pumps we have installed these on trip immediately. two of the pumps are the same model. all three of the breakers are the same manufacturer.
could the issue be start up current imbalance? voltage leakage through capacitors? how do you fix this issue?
your ideas and comments are most welcome and thank you in advance
 
A 7.5 HP single-phase 240v motor shows a FLA of 40 amps in 430.248. I would be suspect that your problem lies the the use of a 60 amp breaker.
Are you attempting to provide OL protection with the breaker or is the thermal or other overload in use ?
For a motor that size a a 80 to 100 amp breaker would be more common-place.
Have you tried starting it on a 6-0 amp non-GFCI breaker ?
 
two of the pumps are Pentair EQ series and the other one is Pentair C series. the breakers are Cutler Hammer BR type.
we are using the Cutler Hammer breakers as they are listed for the kind of panel that is all ready there

the GFI supplies power to a motor starter complete with a thermal overload. the control circuit is supplied separately and not associated with the GFI breaker at all.
I agree the 60 amp rating is low. however, im unaware of a larger amperage available in a GFI. we are "allowed" to size 250% but not required.

we did disconnect the motor leads from the source of power and applied power to the circuit. the breaker will remain on this way. it only trips if the motor load is applied. the capacitors are in good condition, the centrifugal switch appears to be working fine, and the pumps run fine with a standard breaker.
 
stephenweyant said:
two of the pumps are Pentair EQ series and the other one is Pentair C series. the breakers are Cutler Hammer BR type.
we are using the Cutler Hammer breakers as they are listed for the kind of panel that is all ready there

the GFI supplies power to a motor starter complete with a thermal overload. the control circuit is supplied separately and not associated with the GFI breaker at all.
I agree the 60 amp rating is low. however, im unaware of a larger amperage available in a GFI. we are "allowed" to size 250% but not required.

we did disconnect the motor leads from the source of power and applied power to the circuit. the breaker will remain on this way. it only trips if the motor load is applied. the capacitors are in good condition, the centrifugal switch appears to be working fine, and the pumps run fine with a standard breaker.
Click to expand...

Pretty much rules out overload on in rush. So it's got to be the GFCI.
 
@ActionDave
yes the Pentair, Hayward and Jandy variable speed pumps all have nuisance tripping problems. Pentair teamed up with siemens on a special 6ma trip rated GFCI breaker designed especially for these pumps. Pentair even relabeled the breaker and has their own part number! lol
these pumps are equivalent to 3 hp though
 
@LittleBill
I agree with you but question the possibility of imbalance load on start up. so not an overcurrent issue necessarily but still associated with start up current? perhaps something to do with the capacitors and the switch from start to run via centrifugal switch?
shooting in the dark here but we have many 7.5 hp single pumps that need GFCI protection! not to mention some 10 hp single phase pumps!!!
thanks for your help
 
stephenweyant said:
@LittleBill
I agree with you but question the possibility of imbalance load on start up. so not an overcurrent issue necessarily but still associated with start up current? perhaps something to do with the capacitors and the switch from start to run via centrifugal switch?
Click to expand...

I don't think I have ever seen a single phase pool pump motor bigger than 3HP, however I don't think the HP is the issue. I have worked gobs of pool/spa pumps that are cap start as well as sump pumps and so on that have been required to be on GFCIs for some time now and there has not been a problem.
 
@ActionDave
we are in the commercial swimming pool industry and see tons of single phase 7.5 hp pumps. there are even a few 10 hp single phase pumps out there!
NEC states that all single phase swimming pool pump circuits have to be gfci protected. so we have a dilemma if the 60 amp gfci breakers keep tripping on the 7.5 hp pumps.
Im not sure what to do
 
stephenweyant said:
@ActionDave
we are in the commercial swimming pool industry and see tons of single phase 7.5 hp pumps. there are even a few 10 hp single phase pumps out there!
NEC states that all single phase swimming pool pump circuits have to be gfci protected. so we have a dilemma if the 60 amp gfci breakers keep tripping on the 7.5 hp pumps.
Im not sure what to do
Click to expand...

I don't doubt that there are tons of 7.5 and 10HP pumps out there, I'm just not thinking that it's the starting switch in the motor that is causing the GFCI to trip.

What's sucks for you is that there are tons and tons of all sizes of pool pumps without GFCI protection in service that aren't hurting anybody but nobody wanted to consider that when they added new rules. I wish that everybody on the CMPs had to implement all the code changes they approve in their own house or business and all their neighbor's houses and businesses for one code cycle before it could be adopted in the following code cycle.
 
augie47 said:
A 7.5 HP single-phase 240v motor shows a FLA of 40 amps in 430.248. I would be suspect that your problem lies the the use of a 60 amp breaker.
Click to expand...
I'm inclined to agree. Single phase motors are not my area but, like three-phase motors, starting current is probably going to be several times FLC.
 
stephenweyant said:
yes the Pentair, Hayward and Jandy variable speed pumps all have nuisance tripping problems. Pentair teamed up with siemens on a special 6ma trip rated GFCI breaker designed especially for these pumps. Pentair even relabeled the breaker and has their own part number! lol
these pumps are equivalent to 3 hp though
Click to expand...

We have this same problem on the 1.5-2.0 hp Pentair motors if we use any breaker other than a Siemens GFCi. We use the regular Siemens breaker not the rebranded Pentair and they hold fine, on the smaller pumps anyway.

Try the Siemens GFCI, likely solve the problem.
 
I note the references to "GFCI".
Are we really talking about interrupting Ground Fault Current here?
Or overcurrent protection?
Surely they are different functions?

Just a question.
 
Besoeker said:
I note the references to "GFCI".
Are we really talking about interrupting Ground Fault Current here?
Or overcurrent protection?
Surely they are different functions?

Just a question.
Click to expand...
Yes, they are different functions but hard to quickly discern when the breaker itself doesn’t have an indication why it tripped. At least some mfgs have that feature built into their newer AFCI/GFCI breakers. Maybe they will all include it in years to come.
 
ptonsparky said:
Yes, they are different functions but hard to quickly discern when the breaker itself doesn’t have an indication why it tripped. At least some mfgs have that feature built into their newer AFCI/GFCI breakers. Maybe they will all include it in years to come.
Click to expand...
But I suspect we are looking at overcurrent in this specific case. A ground fault would tend to indicate a hard physical fault and you would not be able to close the breaker multiple times. But maybe GFCI is a generic term

We tend to use separate devices for the two functions. But that is often down to customer specificatioon.
 
Little Bill said:
Pretty much rules out overload on in rush. So it's got to be the GFCI.
Click to expand...
presuming both have same instantaneous trip point.

Besoeker said:
I note the references to "GFCI".
Are we really talking about interrupting Ground Fault Current here?
Or overcurrent protection?
Surely they are different functions?

Just a question.
Click to expand...

Besoeker said:
But I suspect we are looking at overcurrent in this specific case. A ground fault would tend to indicate a hard physical fault and you would not be able to close the breaker multiple times. But maybe GFCI is a generic term

We tend to use separate devices for the two functions. But that is often down to customer specificatioon.
Click to expand...
GFCI in the places where NEC is used is a device that responds to leakage current outside the intended circuit conductors, listing requirements for such devices want them to trip if leakage is more then 4-6 mA. They do not respond to short circuits or overloads, though there are types that are incorporated into circuit breakers - but the GFCI function is still a separate portion of those units and when they trip on short circuits or overloads that is the thermal-magnetic components that is tripping.

OP needs to somehow determine if his GFCI breaker is tripping on GFCI functions or thermal-magnetic functions.
 
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