GFCIs and Treadmills

[Sal Ammoniac]

My wife recently got a treadmill and we put it out in the garage, which doubles as an exercise room.

All of the electrical outlets out in the garage are on a circuit with a GFCI. Using the treadmill plugged into any of those outlets will immediately trip the GFCI. When she runs an extension cord into the house and plugs it into a non-GCFI circuit, the treadmill works fine.

Why does the treadmill trip a GFCI and is there any way to prevent this so she doesn't have to run an extension cord into the house to use the treadmill?

[soldar]

I would return it.

[themadhippy]

I would return it.

yep

Why does the treadmill trip a GFCI

because  the electricity  is leaking out and trying to escape ,just hope it dont use your wife as part of its escape route.

[BrianHG]

It's the leakage current into the Earth Ground pin.  Usually, from the class-Y cap being too high between the Hot and Earth Ground.

Remember, some of these GFCI breakers can trip with currents as low at 4ma.

A treadmill has a huge metal chassis and DC motor which will be Earth Grounded, all it can take is too high a class-Y cap with some noisy power, or even some machine oil close to the motor's brushes and it's power lines to excede that 4miliamps tripping your breaker.

Older designs weren't so carefully isolated during UL safety approvals.  A modern treadmill shouldn't get close to this current.

Also with the potential allowed <1ma, if you have other leaky items plugged in all totaling up to ~2-3ma on the same circuit, the treadmill ~1ma to frame ground could be the tripping point.  IE: a few devices, each with a 0.1uf class Y cap on the same circuit will trip the 4ma breaker.  On the other hand, a few devices each with 0.022uf caps wont get close.

My old treadmill's manual states I should use a dedicated circuit for it alone.

[BrianHG]

You can use a class C,D and E GFIC breaker:

Jan 6, 2014 — Class C, D, and E GFCIs trip at 20 mA rather than the 6 mA trip current mandated for Class A GFCIs. This increase in GFCI trip level is ..

[Sal Ammoniac]

The belt on a treadmill looks very similar to the belt on a Van de Graaff generator--could the treadmill be using the power cord's ground line to dump the static electricity generated by the belt and that's what trips the GFCI?

[BrianHG]

The belt on a treadmill looks very similar to the belt on a Van de Graaff generator--could the treadmill be using the power cord's ground line to dump the static electricity generated by the belt and that's what trips the GFCI?

I would not assume that.  The GFCI muse see a good 1/120th of a sec pulse from the 'hot' to trip.

[thm_w]

The belt on a treadmill looks very similar to the belt on a Van de Graaff generator--could the treadmill be using the power cord's ground line to dump the static electricity generated by the belt and that's what trips the GFCI?

You said it immediately trips the GFCI. So it must be the construction/components inside the treadmill and not related to the operation of the device at all.
Unless there is a misunderstanding of what you wrote.

I would personally try to measure the earth leakage out of curiosity, though its not that easy to setup unless you have a good clamp meter.

[BrianHG]

Note that for one of my projects using a treadmill motor, I had to add 1uf caps from the motor's +/- leads to the motor's frame/ IE chassis to get rid of brush commutator noise interfering with my MCU's ADC sampling.  If your treadmill's logic board design needed similar caps, there is nothing you can do, starting up the motor will trip a sensitive GFCI immediately as the motor is usually driven directly by the mains through a Full wave rectifier + scr thyristor or mosfet.  In other words, the motor has a path directly to your mains Hot the moment it moves.  Such commutator noise suppression caps will wire you AC-mains Hot to your chassis ground through said caps tripping your breaker.

You will need to switch to a 20ma tripping GFCI.

[Sal Ammoniac]

The belt on a treadmill looks very similar to the belt on a Van de Graaff generator--could the treadmill be using the power cord's ground line to dump the static electricity generated by the belt and that's what trips the GFCI?

You said it immediately trips the GFCI. So it must be the construction/components inside the treadmill and not related to the operation of the device at all.
Unless there is a misunderstanding of what you wrote.

I would personally try to measure the earth leakage out of curiosity, though its not that easy to setup unless you have a good clamp meter.

I will have to actually observe this issue myself. I've only had my wife's description and don't know the actual timing--whether the breaker trips as soon as she turns the treadmill on, or whether it's after the belt has been moving for some short period of time.

[tom66]

The belt on a treadmill looks very similar to the belt on a Van de Graaff generator--could the treadmill be using the power cord's ground line to dump the static electricity generated by the belt and that's what trips the GFCI?

Even if it was doing something like this, a GFCI looks at the imbalance between Line and Neutral.  It does not usually measure current through the PE (there are exceptions such as for EVSEs but not the case here.)  I can't see how such an imbalance can occur in such a scenario.

I agree with others, the likely problem is a leakage from the motor to the chassis, the product has a fault.  Using a non-GFCI outlet shows no fault, but risks harming the user.

[Kasper]

Any chance it is AFCI that is tripping, not GFCI?

Is she standing on the treadmill when she turns it on?

Does it trip if she is not standing on it when she turns it on?

[EPAIII]

The problem with discussing a problem like this in a web group is it is almost impossible to know all the circumstances. Everything could be perfectly OK or IT COULD BE A DANGEROUS SITUATION. I don't know which and neither do any of the others who have responded. Some general advise:

If it is a NEW treadmill, I would RETURN it as DEFECTIVE. It either has an actual ground fault and there is a real danger or it is a bad design. In either case, a new item should not trip any of the GFCI devices PERIOD! If it does it is defective in some way and should be returned.

If it is a used treadmill then your choices may be more problematic. You could try to return it, but the seller may not wish to take it back. Or you could have it examined by a competent repair technician and possibly have it repaired.

A third idea may be to have a qualified (licensed) electrician examine the treadmill and the wiring in your garage. It is possible that your existing GFCI devices may have deteriorated and become defective over the years.

A word of warning. The GFCI device is only one type of protection against shocks. Another and probably more important one is the ground wire in the cord/plug or the use of double insulation in the design of the device. DO NOT alter either one of these in an amateur attempt to "solve" the problem. You could easily make it a lot more dangerous.

[dferyance]

Read the manual. My treadmill manual specifically says not to plug into GFCI protected outlet. This is not great as it is generally convenient to keep treadmills in places that require GFCI. I've tried it with GFCI and sure enough I get random shutoffs. So I have my treadmill connected to a non-GFCI outlet even though code requires one where it is located.

Interesting about different GFCI class ratings. Maybe I'll look into that. The manual just says no GFCI at all.

[dferyance]

For example:
IMPORTANT: The treadmill is not compatible with GFCI-equipped outlets

PROBLEM: The treadmill circuit breaker trips during a workout.
SOLUTION: Verify the following: • Make sure the treadmill is plugged into a dedicated 20-amp circuit. • Verify that you do not have the machine on an extension cord or surge protector. • Confirm that the machine is not plugged into a GFCI-equipped outlet or on a circuit that has a
GFCI
-equipped outlet on it.
• Lubricate treadmill deck if necessary

https://content.johnsonfit.com/inc/uploaded_media/735ad83e7ab78941e8045cc7faad3510/owners_guide/3f10af8d9932e71dee9fd0299c13b634.pdf

[soldar]

I cannot imagine how it can be legal to sell a machine that trips a GFCI. 

I cannot imagine how it can be technically justified. Sounds like crap with insufficient insulation.

In Europe the code requires whole house protection so you could not use it.

[BrianHG]

I cannot imagine how it can be legal to sell a machine that trips a GFCI. 

I cannot imagine how it can be technically justified. Sounds like crap with insufficient insulation.

In Europe the code requires whole house protection so you could not use it.

Treadmills with big DC motors, driving 15amp spikes through the commutators and coils within the metal can chassis which is the motor itself will trip sensitive GFCIs.  They actually may need to to pass FCC EMI specifications.  Same goes for some power tools.

[Sal Ammoniac]

For example:
IMPORTANT: The treadmill is not compatible with GFCI-equipped outlets

PROBLEM: The treadmill circuit breaker trips during a workout.
SOLUTION: Verify the following: • Make sure the treadmill is plugged into a dedicated 20-amp circuit. • Verify that you do not have the machine on an extension cord or surge protector. • Confirm that the machine is not plugged into a GFCI-equipped outlet or on a circuit that has a
GFCI
-equipped outlet on it.
• Lubricate treadmill deck if necessary

https://content.johnsonfit.com/inc/uploaded_media/735ad83e7ab78941e8045cc7faad3510/owners_guide/3f10af8d9932e71dee9fd0299c13b634.pdf

Here's what another manufacturer of treadmills says about GFCI-protected outlets:

Most homes are now built with two types of outlets: GFCI (Ground Fault Circuit Interrupter) and AFCI (Arc Fault Circuit Interrupter). Both outlets are designed to trip if there is a hazardous condition detected in the home’s wiring. However, because of the outlet’s design, treadmills and incline trainers do not interact well with GFCI or AFCI outlets.


GFCI outlets are often found in bathrooms and kitchens, and are often identified by the red or white reset switch on the plate. GFCI outlets are designed to flip their breakers if there is too much power flowing through the ground port. Because treadmills and incline trainers use the ground prong on the outlets to disperse static electricity, if you plug your machine into a GFCI outlet, it will likely trip the breaker and shut down the machine. If this is occurring, move the treadmill to a different outlet. GFCI breakers often cover other outlets nearby, including outlets that do not have the red reset switch on the plate, so it is recommended that the treadmill is located in a separate area. It is also important that the treadmill is on a dedicated circuit.

https://www.nordictrackfitness.com.au/support/treadmill-power-issues-style-b/GfciafciOutlets

[Sal Ammoniac]

If it is a NEW treadmill, I would RETURN it as DEFECTIVE. It either has an actual ground fault and there is a real danger or it is a bad design. In either case, a new item should not trip any of the GFCI devices PERIOD! If it does it is defective in some way and should be returned.

Here's some more info. My wife bought this treadmill new about five years ago and has been using it almost daily since then. She's never been shocked by it. I only found out about the GFCI issue last week when I happened to be walking by the inner door to the garage and saw an extension cord coming through the doorway and plugged into an outlet in the hallway inside the house. When I asked my wife about it she told me about it tripping the GFCI when she plugged it into an outlet in the garage. Apparently, she's been using it this way for five years.

I'll have her demonstrate the issue so I can determine exactly when the GFCI trips--either as soon as she turns it on, or after the belt starts moving.

[themadhippy]

GFCI outlets are designed to flip their breakers if there is too much power flowing through the ground port. Because treadmills and incline trainers use the ground prong on the outlets to disperse static electricity, if you plug your machine into a GFCI outlet, it will likely trip the breaker

WALOB ,first i can easily trip an rcd (gfci) without ANYTHING escaping to earth and secondly  static discharge through the ground wont cause an imbalance of current between live and neutral  so the device shouldnt trip.sounds more like there trying to cover  up there iffy design

[BrianHG]

If it were belt static, then the treadmill should work fine during heavy/high humid days.

[Sal Ammoniac]

If it were belt static, then the treadmill should work fine during heavy/high humid days.

The garage has an air conditioner/heater and the humidity is rarely above 40-50%. That's something to look into, however. I can try turning off the AC and running a humidifier in the room to see if that makes any difference.

[m k]

When she runs an extension cord into the house and plugs it into a non-GCFI circuit, the treadmill works fine.

Extension cord from one area to the other is a no-no.

There is a safety barrier between areas.
Don't break it.

[Sal Ammoniac]

When she runs an extension cord into the house and plugs it into a non-GCFI circuit, the treadmill works fine.

Extension cord from one area to the other is a no-no.

There is a safety barrier between areas.
Don't break it.

Hey, what can I say? She's a software engineer. 

[WatchfulEye]

I thought that UL and IEC standards specify a maximum of 0.5 mA of earth leakage current for corded appliances (except heating/cooking appliances which are allowed a bit more).

If such a device had leakage high enough to trip a GFCI, surely it would be non-compliant with the relevant standards?