Pool Pump Madness

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Christoph

Christoph

Master Electrician, Code Official
Location
Coopersburg, PA
Occupation
Electrical Inspector
Hello,

I am looking for some insight on how to best solve this issue:

I was called to a pool pump breaker that keeps tripping when it is hot out. These are the parameters (from the top so to speak):

  • 2-pole 40A Type CH GFI breaker in a load center
  • 6AWG THHN in 1/2” conduit
  • Non-fusible disconnect
  • 7 1/2 hp motor (nameplate attached, sorry for the poor resolution (single phase 230V, 1.15 SF continuous duty))
  • Reading 29A operating current when I got there. Was running for hours before I got there
  • Outside temp was about 85°F
Just upfront they have spent thousands of dollars on roof fans etc and no one has ever addressed the issues present.

In looking it over and doing some math I come up with a required breaker size of 100A and separate thermal protection for the motor. There is no thermal protection I can see anywhere. I doubt the motor has integral thermal protection (I am not great with motor controls).

My questions:
  • How would you solve the thermal overload issue? Are there better or worse solutions for motor starters?
  • How would you provide GFI protection for the motor if I were to put a 100A breaker in (which my boss is already fighting me on. He said he has never put anything bigger than 125% FLC/FLA breaker in for a motor.)
  • Is excessive heat a factor in higher operating currents for motors and that’s what would trip the breaker?

Thank you.

Christoph
 

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It may be due to heat generated in or at the breaker.

A 40 amp breaker does seem low for a 30 amp motor.
 
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What is the actual temperature at the breaker itself? It is listed and tested to hold its rated current at 40°C (104°F). That can easily be exceeded and the trip point will be lower.

The code would permit a 100 amp breaker to supply that motor as the code current is 40 amps and Table 430.52 permits 250% for a thermal magnetic breaker. It would still need GFCI protection and you would probably have to use a magnetic starter with overloads that are only sensitive to current and not to the temperature of the overload.
 
50A 2-pole GFCI breakers are very common and can be the cheapest to buy. Try swapping it with a 50A. That is still well within the over current limits and will give a bit more margin. Now if its the GFCI portion that is tripping, then that is something else...

Also, what is the conduit type and is there an EGC run within it? If so, it may be overfilled and perhaps the insulation was nicked when it was pulled. That motor didn't need #6 conductors, #8 is probably plenty.
 
Also, is this a Pentair EQ series pump? If so, its manual says "Some single-phase pumps may contain an internal thermal protector designed to temporarily stop the pump if the motor exceeds a preset temperature. Three-phase pumps do not contain an internal thermal protector and must be externally protected by an appropriately sized protective device commonly referred to as a starter. Improper sizing of the starter can result in the motor being destroyed or in frequent tripping of the starter.". So look carefully on the motor housing for the thermally protected marking somewhere. All pool pumps I ever had were all thermally protected, but none were ever this large.

You may want to call the pump manufacturer to find out how TP is marked and if they know your pump is typically thermally protected or not. Otherwise, you may be messing with a starter and overloads.
 
suemarkp said:
Also, is this a Pentair EQ series pump? If so, its manual says "Some single-phase pumps may contain an internal thermal protector designed to temporarily stop the pump if the motor exceeds a preset temperature. Three-phase pumps do not contain an internal thermal protector and must be externally protected by an appropriately sized protective device commonly referred to as a starter. Improper sizing of the starter can result in the motor being destroyed or in frequent tripping of the starter.". So look carefully on the motor housing for the thermally protected marking somewhere. All pool pumps I ever had were all thermally protected, but none were ever this large.

You may want to call the pump manufacturer to find out how TP is marked and if they know your pump is typically thermally protected or not. Otherwise, you may be messing with a starter and overloads.
Click to expand...
Any such internal overload protection is required to be marked on the motor nameplate per 430.7(A). I don't see any such marking.
 
suemarkp said:
Also, is this a Pentair EQ series pump? If so, its manual says "Some single-phase pumps may contain an internal thermal protector designed to temporarily stop the pump if the motor exceeds a preset temperature. Three-phase pumps do not contain an internal thermal protector and must be externally protected by an appropriately sized protective device commonly referred to as a starter. Improper sizing of the starter can result in the motor being destroyed or in frequent tripping of the starter.". So look carefully on the motor housing for the thermally protected marking somewhere. All pool pumps I ever had were all thermally protected, but none were ever this large.

You may want to call the pump manufacturer to find out how TP is marked and if they know your pump is typically thermally protected or not. Otherwise, you may be messing with a starter and overloads.
Click to expand...
I called with the model vendor said it is exclusive to Pentair products and to get data from them
 
Christoph said:
Hello,

I am looking for some insight on how to best solve this issue:

I was called to a pool pump breaker that keeps tripping when it is hot out. These are the parameters (from the top so to speak):

  • 2-pole 40A Type CH GFI breaker in a load center
  • 6AWG THHN in 1/2” conduit
  • Non-fusible disconnect
  • 7 1/2 hp motor (nameplate attached, sorry for the poor resolution (single phase 230V, 1.15 SF continuous duty))
  • Reading 29A operating current when I got there. Was running for hours before I got there
  • Outside temp was about 85°F
Just upfront they have spent thousands of dollars on roof fans etc and no one has ever addressed the issues present.

In looking it over and doing some math I come up with a required breaker size of 100A and separate thermal protection for the motor. There is no thermal protection I can see anywhere. I doubt the motor has integral thermal protection (I am not great with motor controls).

My questions:
  • How would you solve the thermal overload issue? Are there better or worse solutions for motor starters?
  • How would you provide GFI protection for the motor if I were to put a 100A breaker in (which my boss is already fighting me on. He said he has never put anything bigger than 125% FLC/FLA breaker in for a motor.)
  • Is excessive heat a factor in higher operating currents for motors and that’s what would trip the breaker?

Thank you.

Christoph
Click to expand...
I tried to scan the barcode from your picture but it did not work. If your phone has the scan app it may be helpful finding direct info on this motor. Nidec says its a pentair exclusive call them for data.
 
Don said the first VERY important piece of the puzzle, then he stated the other part. I will reiterate for clarity. 430.247 says that you are supposed to use 40 amps to size your breaker and 430.52 allows a maximum of 250% for an inverse time circuit breaker. 40*2.5=100A So that is the maximum breaker size. It can be smaller, but 40 is surely too low. I might try a 60A if I had one laying around for free, otherwise, might as well get the 100A GFCI period. You already have a tripping problem, why would you go smaller.

Second Don said no you don't have integral thermal protection, so you need a motor starter to provide that. You base that rating on the current rating listed on the nameplate.

It is kind of irritating when you run across stuff installed like this with no regard for code and likely a passed inspection.
 
Christoph said:
Hello,

I am looking for some insight on how to best solve this issue:

I was called to a pool pump breaker that keeps tripping when it is hot out. These are the parameters (from the top so to speak):

  • 2-pole 40A Type CH GFI breaker in a load center
  • 6AWG THHN in 1/2” conduit
  • Non-fusible disconnect
  • 7 1/2 hp motor (nameplate attached, sorry for the poor resolution (single phase 230V, 1.15 SF continuous duty))
  • Reading 29A operating current when I got there. Was running for hours before I got there
  • Outside temp was about 85°F
Just upfront they have spent thousands of dollars on roof fans etc and no one has ever addressed the issues present.

In looking it over and doing some math I come up with a required breaker size of 100A and separate thermal protection for the motor. There is no thermal protection I can see anywhere. I doubt the motor has integral thermal protection (I am not great with motor controls).

My questions:
  • How would you solve the thermal overload issue? Are there better or worse solutions for motor starters?
  • How would you provide GFI protection for the motor if I were to put a 100A breaker in (which my boss is already fighting me on. He said he has never put anything bigger than 125% FLC/FLA breaker in for a motor.)
  • Is excessive heat a factor in higher operating currents for motors and that’s what would trip the breaker?

Thank you.

Christoph
Click to expand...
Christopher the FLC in the NEC is 40amps for that motor
short circuit Ground fault i agree breaker 40*250%=100amp
wire 40*1.25=50amp number #6

If using THHW and 1/2" conduit that is to small from annex C table C10 not sure if that would cause this.


In the link page 2 it seems to say all models require external thermal OL protection if this is your model.
 
Thank you everyone for your input.

We are going to provide a proposal to the customer for a motor starter with thermal overload protection and get the biggest available GFI breaker available. (Probably 50 or 60A) Setting expectations here is the name of the game for us as we do not know the internal condition of the motor at this point (supposedly tripped daily for years during heat waves, so who knows how much insulation is left on those windings.

For anyone questioning the GFI vs overcurrent tripping of the breaker: the tripping is always heat related (ambient temp that is) so I am not really feeling the GFI tripping scenario. I applaud any manufacturer that makes OCP with indicator LEDs that show if the GFI or the overcurrent part tripped it.

A very valuable comment here was that breakers trip at their rates current at 40°C. I always wondered what the 40°C meant on the breakers. They surely wouldn’t have 40°C terminals 🥸. I know that column does not exist.
The panel containing the breaker is outdoors. Although I am not sure of the Sun exposure we will surely see temps way upwards of 40° in there. So that was a “hot” tip.

I am not going to loose any sleep over wire and conduit sizes here. It is all PVC being in a pool equipment room (corrosive environment per Art. 680).

The other comment on how this would have passed before is a mystery to me. Around our parts in PA anyway there is a lot of butchery going on. See attached pictures on THIS job, same motor we have been talking about. This was re-certified weeks ago being a public pool by an inspector.

We clearly have work to do in quality and compliance in this country in this industry.

Thanks again everyone, I will post any interesting updates before this post gets closed.
 

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Christoph said:
Thank you everyone for your input.

We are going to provide a proposal to the customer for a motor starter with thermal overload protection and get the biggest available GFI breaker available. (Probably 50 or 60A) Setting expectations here is the name of the game for us as we do not know the internal condition of the motor at this point (supposedly tripped daily for years during heat waves, so who knows how much insulation is left on those windings.

For anyone questioning the GFI vs overcurrent tripping of the breaker: the tripping is always heat related (ambient temp that is) so I am not really feeling the GFI tripping scenario. I applaud any manufacturer that makes OCP with indicator LEDs that show if the GFI or the overcurrent part tripped it.

A very valuable comment here was that breakers trip at their rates current at 40°C. I always wondered what the 40°C meant on the breakers. They surely wouldn’t have 40°C terminals 🥸. I know that column does not exist.
The panel containing the breaker is outdoors. Although I am not sure of the Sun exposure we will surely see temps way upwards of 40° in there. So that was a “hot” tip.

I am not going to loose any sleep over wire and conduit sizes here. It is all PVC being in a pool equipment room (corrosive environment per Art. 680).

The other comment on how this would have passed before is a mystery to me. Around our parts in PA anyway there is a lot of butchery going on. See attached pictures on THIS job, same motor we have been talking about. This was re-certified weeks ago being a public pool by an inspector.

We clearly have work to do in quality and compliance in this country in this industry.

Thanks again everyone, I will post any interesting updates before this post gets closed.
Click to expand...
I have seen sun shades added for outdoor panels to limit the sun exposure and as a result limit the ambient temperature at the breaker.
 
Christoph said:
Thank you everyone for your input.

We are going to provide a proposal to the customer for a motor starter with thermal overload protection and get the biggest available GFI breaker available. (Probably 50 or 60A) Setting expectations here is the name of the game for us as we do not know the internal condition of the motor at this point (supposedly tripped daily for years during heat waves, so who knows how much insulation is left on those windings.

For anyone questioning the GFI vs overcurrent tripping of the breaker: the tripping is always heat related (ambient temp that is) so I am not really feeling the GFI tripping scenario. I applaud any manufacturer that makes OCP with indicator LEDs that show if the GFI or the overcurrent part tripped it.

A very valuable comment here was that breakers trip at their rates current at 40°C. I always wondered what the 40°C meant on the breakers. They surely wouldn’t have 40°C terminals 🥸. I know that column does not exist.
The panel containing the breaker is outdoors. Although I am not sure of the Sun exposure we will surely see temps way upwards of 40° in there. So that was a “hot” tip.

I am not going to loose any sleep over wire and conduit sizes here. It is all PVC being in a pool equipment room (corrosive environment per Art. 680).

The other comment on how this would have passed before is a mystery to me. Around our parts in PA anyway there is a lot of butchery going on. See attached pictures on THIS job, same motor we have been talking about. This was re-certified weeks ago being a public pool by an inspector.

We clearly have work to do in quality and compliance in this country in this industry.

Thanks again everyone, I will post any interesting updates before this post gets closed.
Click to expand...
First off, with everything you are describing, I doubt the motor has taken any damage. It was never overloaded, the breaker was tripping because it couldn't handle the actual amperage required to start and run the motor. (That is unless the motor was running hot, which is possible because it doesn't have overloads.)

Next, breakers. A breaker is a thermal magnetic trip, when high amperage travels through the breaker it heats the breaker up once the (usually) bimetallic lever heats up enough the magnetic pull overcomes the spring and trips the breaker. The spring will also release and trip the breaker when the amperage is really high (6-10 times the current rating) instantly. I describe typical long time and instantaneous trip functions. That said, a breaker rated for 40 degrees means that at 40 degrees there is enough the breaker will operate within its tolerance for trip time and amperage. When the breaker is in a cold or hot environment, it will either trip more slowly or more quickly at borderline amperages. So, it just adds one more layer as to why your breaker keeps tripping. High ambient temperature, amperage too close to the tolerance. BTW a typical tolerance is 20% so, a 40 amp breaker could trip at 30 amps, but it is likely to take hours before it trips.
 
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