Breaker question

[Newdude]

There are none that trip at 3 milliamps.

A class A device can trip anywhere between 4-6ma and be acceptable in design, but it must trip above 6ma

Apologies for however I am miscommunicating the breaker designed for the VS pumps. The point was to ensure the new specs were the same with the old discontinued breaker designed for the pumps.

 

[ImpalaSS]

Breakers protect the wire. Never put a larger breaker than your wire can handle. What gauge is your wire? Have you tried another SquareD 20 amp?

M,

The size of the breaker is determined by the wire size connected to the breaker and not the load (motor)..

So no.

Thanks,

Jim R.

You both are right when it comes to overcurrent protection of branch circuits or feeder. But when it comes to motors the wire size is determined by the name plate amperage on the motor NOT THE BREAKER. Depending on the motor amperage it may be fine to power a motor with a 30a breaker and still have #12 wire.

 

[laprjns]

Depending on the motor amperage it may be fine to power a motor with a 30a breaker and still have #12 wire.

This is only allowed in very specific applications, i.e a dedicated hardwired circuit to an air conditioner or motor with its own over current protection. In this case the equipment protects the wire from overload. From what I found it seem like a this is discourage, and relying on sizing the wire based on the load it will carry and then sizing the breaker based on the wire being use is the norm.

 

[PoolGate]

You both are right when it comes to overcurrent protection of branch circuits or feeder. But when it comes to motors the wire size is determined by the name plate amperage on the motor NOT THE BREAKER. Depending on the motor amperage it may be fine to power a motor with a 30a breaker and still have #12 wire.

Motors draw a lot of power (surge) when they start. So it makes sense on that front. But they also sell slow-blow breakers for this purpose. In either case, 20 amps way out-rates the motor draw so I would suspect something else is going on. And any surge should be minimal when going between speeds. I would suggest further investigation perhaps see if the pump is still under warranty.

 

[ImpalaSS]

This is only allowed in very specific applications, i.e a dedicated hardwired circuit to an air conditioner or motor with its own over current protection. In this case the equipment protects the wire from overload. From what I found it seem like a this is discourage, and relying on sizing the wire based on the load it will carry and then sizing the breaker based on the wire being use is the norm.

See NEC Article 430 to size the overcurrent protection for motors. Wire size is based on motor amps, not overcurrent protection. There is no "..seems like.." or "...the norm.." in safe NEC compliant electrical installations.

 

[Orion7319]

I was able to buy one online from HomeDepot on Tuesday and it shipped today. I guess they go fast! Hopefully they will have them in stock again soon.

 

[ajw22]

See NEC Article 430 to size the overcurrent protection for motors. Wire size is based on motor amps, not overcurrent protection. There is no "..seems like.." or "...the norm.." in safe NEC compliant electrical installations.

At one time the NEC specified pool pumps shall be on a dedicated circuit. Within the last few NEC revisions the requirement for a dedicated circuit was dropped.

It would make sense that the wire size can be based on motor amps is the motor is on a dedicated circuit. However if other loads are put on the same circuit then the circuit can overload the wire size and not the CB.

The requirement for a pool pump motor on a dedicated circuit conflicted with the practice of powering the SWG on the same circuit as the pump. And sometimes the gas heater is put on the pump circuit.

So how does the NEC keep a motor circuit from overloading the wire size if it is not on a dedicated circuit?

 

[CJadamec]

At one time the NEC specified pool pumps shall be on a dedicated circuit. Within the last few NEC revisions the requirement for a dedicated circuit was dropped.

It would make sense that the wire size can be based on motor amps is the motor is on a dedicated circuit. However if other loads are put on the same circuit then the circuit can overload the wire size and not the CB.

The requirement for a pool pump motor on a dedicated circuit conflicted with the practice of powering the SWG on the same circuit as the pump. And sometimes the gas heater is put on the pump circuit.

So how does the NEC keep a motor circuit from overloading the wire size if it is not on a dedicated circuit?

Section 680.21 (a)(1) states at a minimum all wires feeding a pump will be insulated and not smaller than 12gauge.

In addition 680.22 (a)(1) requires the addition of separately wired 15 or 20 general purpose outlet.

Outside of those requirements you need to follow the other code sections as they apply to wire size a breaker protection.

Where the pump isn't on a dedicated circuit you need to size the protection and wire for the mixed use.

An important thing to note about the particular pump mentioned in this post is that it is a VS pump. This pump has virtually zero inrush current because it's a soft start motor. Motor inrush is not causing the GFCI breaker to trip in this case because it's not there.

Motor inrush is also the reason dedicated pump circuits get larger breakers than you would otherwise use for the wire often up 150% standard ratings. Those types of motor circuits typically also are equipped with time delay fuses sized for the wire or expected full running amps. Or the motor control is equipped with thermal overloads. None of these types of circuits are common in residential settings. The exception being large HVAc equipment.

Speed changes on VS pumps do case line imbalances and harmonic feedback when changing speeds. Weak or overly sensitive GFCI devices will false trip under these conditions.

 

[Orion7319]

Speed changes on VS pumps do case line imbalances and harmonic feedback when changing speeds. Weak or overly sensitive GFCI devices will false trip under these conditions.

I have worked with audio/video/ concert and broadcast equipment my entire adult life. I have never heard the term harmonic feedback applied to electricity, but then again all I usually haven to worry about is the 60hz hum…Interesting.

 

[JamesW]

I have never heard the term harmonic feedback applied to electricity

Audio and video are electrical signals.

 

[CJadamec]

Industrial speed controls and variable frequency drives can play all sorts of havoc with electrical system. Sensitive electronics like GFCI devices measuring milliamp differences in current don't like even a little bit of havoc.

A/C power quality can have all sorts of harmonic distortion in the power. Your audio equipment has lots of filtering devices to deal with most of these issues and they typically aren't bother by million level distortion on the incoming power side.

 

[Orion7319]

Audio and video are electrical signals.

Yes they are! I just don’t typically think of AC power in terms of sine waves and square waves!

 

[JamesW]

https://www.grainger.com/know-how/safety/electrical-hazard-safety/advanced-electrical-maintenance/kh-electrical-power-system-harmonics

 

[ImpalaSS]

Doing an install now with VFD's, harmonic filter panels and AVR's. There is all kinds of harmonic distortion on rail systems.

 

[CJadamec]

You should see what older speed drives on large cranes do to power systems. Don't get me started on DC drives with Regen braking.

 

[Orion7319]

https://www.grainger.com/know-how/safety/electrical-hazard-safety/advanced-electrical-maintenance/kh-electrical-power-system-harmonics

​

Good article!

“What Causes Harmonics?
Harmonics are created by electronic equipment with nonlinear loads drawing in current in abrupt short pulses. The short pulses cause distorted current waveforms, which in turn cause harmonic currents to flow back into other parts of the power system. Harmonics are especially prevalent when there are many personal computers, laser printers, fax machines, copiers, or medical test equipment, fluorescent lighting, uninterruptible power supplies (UPSs), and variable speed drives all on the same electrical system.”

 

[Orion7319]

Industrial speed controls and variable frequency drives can play all sorts of havoc with electrical system. Sensitive electronics like GFCI devices measuring milliamp differences in current don't like even a little bit of havoc.

A/C power quality can have all sorts of harmonic distortion in the power. Your audio equipment has lots of filtering devices to deal with most of these issues and they typically aren't bother by million level distortion on the incoming power side.

I was thinking at the time more in terms of audio waves… but it’s all waves I suppose..

What Is Total Harmonic Distortion In Audio And Microphones? | My New Microphone

Love it or hate it, distortion is something we should always be listening for in our microphones, audio chain, and playback. Measuring distortion quantitatively is…

mynewmicrophone.com

 

[Orion7319]

https://www.grainger.com/know-how/safety/electrical-hazard-safety/advanced-electrical-maintenance/kh-electrical-power-system-harmonics

So I would imagine LED lights would contribute to this as well nowadays. I have encountered indoor LED lights that were using pulse width modulation in frequencies that would play complete havoc with our cameras shutter speeds…

Resources - Lighting Terms - Pulse Width Modulation

www.environmentallights.com

 

[moore887]

Hi All,

It's been a really busy week and I haven't had much time but I need to put this to bed. I have been communicating with George Keathly who is the Jacuzzi technical manager for Leslie's. He echoes a lot of what is mentioned by the brilliant people here in terms of the sensitivity of the currently installed SquareD gfci breaker and indeed mentions the Siemens 20amp being a suitable alternative. Leslie's service center to hold firm that they are waiting on parts for the pump (4 weeks now) before they will call out but I can't seem to get an answer as to what parts they are waiting for.

So my question today is if anyone can link me to a suitable breaker that I could purchase, preferably at one of the home stores, that would slot into the squareD panel?

I am not discounting the ideal that the pump could indeed be at fault. Ideally, I would like to see that being completely swapped out to maybe even one of the newer Hayward clone Jacuzzi pumps that recently went on sale at Leslie's.

Regards

Dave

 

[PoolGate]

You could always bite the bullet and pay the extra for the siemans on eBay there are several.