GFCI Trip Current and washing machines - follow up to amps kill education thread

[archibald tuttle]

Having a devil of a time keeping washers running on GFCIs without tripping. Of course in the 'good' ole days there were no GFCIs and it varies whether these washers are near sinks or theoretically required to have GFCI, but I'm wondering whether the industry has considered single purpose GFCIs with higher fault current settings.

I understand that whole house protections have noticeably higher settings to ease false [actually meant nuisance] tripping. So it seems that in some circumstances the industry makes rational accommodation. Of course that doesn't consider that a relatively small current can kill, but one wonders if nusiance tripping - and thus the more widespread employement of the safety technology might not suggest washing machine outlets that have a single outlet for the washer alone and trip at a slightly higher current given that the washer itself has a grounded frame and that current seeks all paths to ground relative to resistance, it isn't necessary to simply assess the load relative to the resistance of the body hand to hand but also to compare that resistance to other paths kept open to protect against likely fault incidents at the low end of the scale.

Unfortunately, these happenings with our machines are transient and I can't reproduce them on cue to diagnose, so half the time the machine doesn't stop mid cycle, but the other half it does.

You can't live your life like this. better to have a switch for denergizing the washer before going near it than to have a washer that doesn't complete it's cycle half the time.

Suppose it might be relevant to relative danger whether there is a metal laundry sink or piping nearby that the user could also contact enhancing the possibility of becoming part of a circuit, but could that be mitigated by some local bonding to the washing machine. Of course that puts the same voltage on the sink that is on the machine body, but that prevents the sink from becoming the other hand ground for the body.

Of course this goes against the general principle of only bonding at the service and might introduce other spurious dangers I'm not thinking of although given the fact that the most of us survived so many years with no GFCI protection at all just employing a modest respect for electricity, I'm not convinced how far we should chase our tail in these danges. and ultimately, nuisance trips only lead to bypassing or giving up on any protection altogether, esp. if that which is nuisance tripping is a 500 dollar appliance and the trips are transient and difficult to track down.

just thinking this stuff through and now that I've run out of brain power, submitting it to the groupthink.

brian

 

[iwire]

In a nutshell the problem is with the washer not the GFCI.

Higher current levels would not provide personal protection which is the pont

The higher current devices are for equipment protection only

 

[Sahib]

In a nutshell the problem is with the washer not the GFCI.

Higher current levels would not provide personal protection which is the pont

The higher current devices are for equipment protection only

But some devices such as data processing equipment such as computers are 'naturally problematic' in that they have a ground leakage current so that a GFCI would trip on them.

It seems because of such reasons, IEC, the other international standard to IEEE, permits 30mA GFCI in residences.

 

[iwire]

There is no such thing as a 30 mA GFCI in America.

Strange that tens of thousands of washers work fine on GFCIs and these ones do not.

I would say it is a defect in the machine

 

[archibald tuttle]

not saying it isn't a problem with the washer . . .

not saying it isn't a problem with the washer . . .

. . . and I'm not saying that there aren't lots of washers that run fine on GFCI. but as posted above there are places that have a looser standard but a standard nonetheless, and just because there is a certain standard in America doesn't make it right. There are also hundreds and hundreds of washers in America that aren't on GFCI's at all and they aren't regularly killing people so you have to balance the difficulty and cost of regulating minor faults in a water bearing appliance with the safety obtained. I'm wondering if there is a middle ground, which by the 30 ma standard ain't exactly moving the goal posts a long way.

I follow from the earlier thread I referenced that the very low trip current standard now employed for GFCI's in America is designed to stay below current that can theoretically kill someone. I get that, but what I don't get is why there is an assumption that the entire fault current is being delivered to the person. The fault finds ground along all paths relative to resistance. Now there could be some ground fault circumstances in which a person is the only ground but that seems highly unlikely if good frame grounding is engaged for laundry appliances that has long been the rule of practice.

Then, if I recall what has also been drilled into me, current follows all paths to ground relative to resistance. So you have to compare the resistance of the path through the person and the provided path from the frame down the ground wire to get a sense of how much current going loose in a washer is likely to go to a person who touches the washer and something else grounded while the fault is occuring. So simply raising the trip current for an outlet servicing only a washing machine doesn't appear to pose a significant hazard depending on how high you raise it.

There are some things that is is obvious you let the highly sensitive fault monitor control, so if you're using your 2 wire hair dryer next to the sink and it trips the ground fault, you don't think about buying a less sensitive ground fault or using a non-protected outlet (well actually, some people do but . . . ), you get another hair dryer, which these days have their own built in ground faults.

But the price of a washer and the price of tracing spurious faults in them that don't even occur every cycle are a barrier to wider adoption of GFCI protection, so rather than tow the company line, I'm asking for thoughtful alternatives that may not now be available or within code but might be worth considering in the future. I had offered the notion of a single plug so folks couldn't plug other stuff, say 2 wire irons into them. But you could also use a different plug style as well, so they couldn't unplug the washer and plug something else in because the blades would be differently oriented.

That's why we have different plugs for different voltages and amperages, to defeat folks doing stuff that wouldn't be wise and could lead to hazards.

And in the nfn department, whats the real point of having a GFCI washer if it is sitting right next to potentially in contact or commonly bonded metal dryer?

I have yet to encounter a dryer on a GFCI although its theoretically possible and they are in the same damp environments and often adjacent to laundry sinks.

Probably if I was called in to service dryers in very new construction that are proximate to sink installations, maybe I would have.

brian

 

[suemarkp]

Aren't GFCI's in laundries only required if near a laundry sink? A washing machine in a room with no sink doesn't require a GFCI unless there are other GFCI rules requiring it (unfinished basement, garage, bathroom).

 

[archibald tuttle]

precisely

precisely

Aren't GFCI's in laundries only required if near a laundry sink? A washing machine in a room with no sink doesn't require a GFCI unless there are other GFCI rules requiring it (unfinished basement, garage, bathroom).

requirement is in areas where it is easier to find another pathway to ground, so I have a solution in that the one I'm working on right now has no sink nearby and its a finished first floor. But, I'm thinking ahead to the next call I get when that is not the case -- and I'm extrapolating that most homeowners are not going to stick with GFCI if they can't run their washing machines.

I'm not encouraging people to ignore the requirements or asking anyone to encourage me to do the same, just to cover the basics so moderators don't get the wrong idea. What I'm thinking about is that this site has had a lot of fruitful discussion about the code and useful changes. I started this thread as a question about the availability of those 30ma trip current GFCIs which I had heard about, but if they are outside American parameters, than it has morphed more into a discussion of why, and whether there are particularized circumstances that the code might be changed to accommodate them.

thanks, brian

 

[suemarkp]

The 30ma trip devices are called AFCI's here. But I don't think that is going to increase reliability either, as the arc fault circuitry can have tripping issues too with certain load types or environmental factors.

 

[GoldDigger]

The 30ma trip devices are called AFCI's here.

Yes and no. Early through fairly recent AFCIs incorporated ground current detection at the 30ma level as a bonus feature, in part because there was concern (justified) that the devices would not be able to detect a small but potentially dangerous parallel arc fault to ground.
But there are currently AFCIs available without the ground current detection feature. You have to read the spec to see what you are getting.

 

[iwire]

To the NEC a GFCI is a device made to protect people, to that end its trip range is about 6mA.

A device with a higher trip range is not a GFCI, those devices are GFP and are not designed or intended to protect people from shocks, they are intended to protect equipment.

If you are in a location that 210.8 applies to you must use a GFCI not GFP.

 

[don_resqcapt19]

The UL standard for appliances limits the maximum leakage current to 0.5mA or ~10% of the GFCI trip point. If the washer is tripping the GFCI there is a problem with the appliance.

 

[Fliz]

Whenever someone says "what if it doesbnt work?" with reference to ground faults and arc faults, I say it means they have a ground fault or an arc fault.

Another way to phrase your question is: "why cant machines that produce hazardous currrents work with these protective devices?". Doesn't make sense.

 

[gar]

130711-2013 EDT

archibald tuttle:

A GFCI has an upper limit trip value of 6 mA after a substantial time of presence. At shorter times the trip point is considerably higher. You do not want to be shocked by even 6 mA. At the moment I do not want to look up the trip time curve limit, but you should.

If any load is causing false tripping of a GFCI, then the load is at fault, and the manufacturer of the product should be made to solve the problem.

At 120 V 6 mA is 20,000 ohms. At 60 Hz a capacitance of about 0.16 mfd would equal 20,000 ohms. Some noise filters with shunt capacitors from line to chassis (equals EGC) might have capacitors in this range. These could be a problem. Thus, noise filters have to be designed to have a sufficiently low shunt current to ground to not cause GFCI problems.

Very large line voltage transients, probably in the several thousand volt range, may cause false GFCI tripping.

Since you only have the false tripping resulting from the operation of the washing machine, then you need to contact the washing machine manufacturer for a solution.

False AFCI tripping is an entirely different story.

.

 

[don_resqcapt19]

130711-2013 EDT
A GFCI has an upper limit trip value of 6 mA after a substantial time of presence. At shorter times the trip point is considerably higher. You do not want to be shocked by even 6 mA. At the moment I do not want to look up the trip time curve limit, but you should. ...

While a long trip time is permitted by the standard, most GFCI breakers trip much quicker than the maximum time permitted by the standard.

The standard permits a time to trip in seconds that is equal to the quantity (20/fault current in milliamps) raised to the 1.43 power.

 

[archibald tuttle]

read that on the original amps kill thread

read that on the original amps kill thread

While a long trip time is permitted by the standard, most GFCI breakers trip much quicker than the maximum time permitted by the standard.

The standard permits a time to trip in seconds that is equal to the quantity (20/fault current in milliamps) raised to the 1.43 power.

so doing some rudimentary calculations and simplying to the power of 1.5 which resolves to the square root of the cube and assuming that the the standard is 6 ma thats 20/6 = 3.333_ which cubed is about 37 the square root of which is a little more the 6 so call it 6 seconds.

I realize that I had focused on trip current and not timing although I'm aware that the two are modestly interchangeable when dealing with a heat tripped current sensing set up because the heat builds up over the time that the fault current is observed across the tripping feature.

I guess this raises my original question in a slightly different way which is, are there ground faults manufactured exactingly to take advantage if the maximum timing -- and or what testing protocols might be available, say android ap as I think about it that could say hook up to the usb and provide a graph of current in the grounding conductor over time so I could measure the size and duration of these transients.

and reviewing 210.8 I see exceptions that would apply to laundry equipment in basements and garages but not to laundry equipment that is plugged in within 6 feet of a sink in a laundry room, I guess we can debate whether you could have sink in a basement or garage within 6 feet of the outlet serving the laundry but I don't see why not under the exception. (caveat, I'm reading a 2005 version here so I stand to be corrected if there have been changes since then).

so in many circumstances there are outright exceptions for 'installed' equipment that is unlikely to be moved. see also the exception that in kitchens GFCI requirements apply only to outlets serving counters so there is an implicit exception if you serve your refrigerator with an independent not commonly accessible outlet and ranges wouldn't require it other without regard for the distance of the applicance to the sink.

For that matter, the same is true of the text applying to laundry rooms which simply calculates by the distance of the outlet from the sink. but appliance with 3 foot cord could be plugged into non-protectd outlet 6 feet from sink but be closer. Which doesn't seem like much of a problem to me, but I wonder whether research and discussion of an some other standard for tripping could lead to wider adoption of some protection for laundry appliances even if it does prevent virtually every theoretical lethal encounter.

I appreciate and agree that the GFCI is detecting a 'problem' with the appliance. I'm questioning whether the standard and or outlets that function quicker than the most liberal timing allowance of the standard are actually providing more safety from shock hazard if, in the majority of cases one can choose simply to take advantage of the exception.

Wouldn't it make more sense to study the pattern of fault currents in these appliances and consider allowing GFCI protection that operated on a different standard esp. based on the point I have been making which seems to undergird these exceptions that installed appliances have grounded frames and thus don't present the same likelihood of passing the entire fault current to a user.

Indeed, the past practice was directly bonding the laundry appliances to the water pipes nearby that would place the faucet and sink at essentially the same potential as the body of the appliance thus rendering less likely a hand to hand shock.

I can see reasons that GFCI protection might be preferable but I can't see homeowners spending hundreds of dollars diagnosing transient faults in appliances, nor do I think it likely that this can be put back on manufacturers unless a common source of fault can be identified -- kind of like an automotive recall.

It isn't clear at this point what the costs of chasing these on a macro scale might be and I'm sure if there are simple answers that manufacturers would not be resistant to designing those in, but I wouldn't like to see the consumers who ultimately pay the cost forced to have unnecessary safety spending. And yes I think there is such a thing.

brian

 

[don_resqcapt19]

I have never tested the trip time of a GFCI, but there have been posts from people who have. In general they tripped at 1/4 or less or they did not trip.

The exceptions in 210.8(A) were all removed in the 2008 code.

As I said before the maximum permitted leakage current for an listed appliance is 0.5mA. There is no reason to make any changes other that to get the appliance fixed.

 

[K8MHZ]

Brian,

Have you check out any of the washers for problems?

A leaky seal getting water on the motor may trip a GFCI. Sometimes that's evident just by looking.

Have you megged out any of the washers that pop a GFCI?

I would work on finding out what is wrong with the machines, not on looking for ways to circumvent a safety device (a device that's known and proven to be effective).

 

[iwire]

I realize that I had focused on trip current and not timing although I'm aware that the two are modestly interchangeable when dealing with a heat tripped current sensing set up because the heat builds up over the time that the fault current is observed across the tripping feature.

There is no heat involved with the GFCI sensors and trip.

I guess this raises my original question in a slightly different way which is, are there ground faults manufactured exactingly to take advantage if the maximum timing -- and or what testing protocols might be available, say android ap as I think about it that could say hook up to the usb and provide a graph of current in the grounding conductor over time so I could measure the size and duration of these transients.

You can purchase ground leakage current testers but I would ask why you would want to?

and reviewing 210.8 I see exceptions that would apply to laundry equipment in basements and garages but not to laundry equipment that is plugged in within 6 feet of a sink in a laundry room, I guess we can debate whether you could have sink in a basement or garage within 6 feet of the outlet serving the laundry but I don't see why not under the exception. (caveat, I'm reading a 2005 version here so I stand to be corrected if there have been changes since then).

The exceptions have been removed.

I appreciate and agree that the GFCI is detecting a 'problem' with the appliance. I'm questioning whether the standard and or outlets that function quicker than the most liberal timing allowance of the standard are actually providing more safety from shock hazard if, in the majority of cases one can choose simply to take advantage of the exception.

The timing and current levels are based on protecting people, increasing either defeats the purpose of the GFCI and is unneeded change as GFCIs work fine with equipment that is in good shape.

The exceptions are not an option any more.

Wouldn't it make more sense to study the pattern of fault currents in these appliances and consider allowing GFCI protection that operated on a different standard esp. based on the point I have been making which seems to undergird these exceptions that installed appliances have grounded frames and thus don't present the same likelihood of passing the entire fault current to a user.

No, it would not make more sense. It would make sense to repair or remove the faulty washer.

Indeed, the past practice was directly bonding the laundry appliances to the water pipes nearby that would place the faucet and sink at essentially the same potential as the body of the appliance thus rendering less likely a hand to hand shock.

The best practice is to fix the fault, not put a band aid on it to hide it.

I can see reasons that GFCI protection might be preferable but I can't see homeowners spending hundreds of dollars diagnosing transient faults in appliances, nor do I think it likely that this can be put back on manufacturers unless a common source of fault can be identified -- kind of like an automotive recall.



It isn't clear at this point what the costs of chasing these on a macro scale might be and I'm sure if there are simple answers that manufacturers would not be resistant to designing those in, but I wouldn't like to see the consumers who ultimately pay the cost forced to have unnecessary safety spending. And yes I think there is such a thing.

brian

Brain, hundreds of thousands of appliances work fine on GFCIs, in my opinion you seem hell bent on fixing a problem that does not exist.

 

[archibald tuttle]

caveats

caveats

I have never tested the trip time of a GFCI, but there have been posts from people who have. In general they tripped at 1/4 or less or they did not trip.

The exceptions in 210.8(A) were all removed in the 2008 code.

As I said before the maximum permitted leakage current for an listed appliance is 0.5mA. There is no reason to make any changes other that to get the appliance fixed.

so up until 2008 these exceptions were conventional but as of 2008 the electrons started doing different things? I think you would concede that the original existence of those exceptions at least contemplates the cost benefit thinking I'm doing here and was aimmed relatively precisely at the kind of circumstances I'm encountering.

I don't know that the changes in 2008 are right or wrong, but I appreciate your pointing them out.

Some parts of the code to which I refer as logical exceptions were not textually exceptions. for instance kitchen outlets were required to have GFCI protection if they served counters . was this language changed as well?

LAundry rooms were required to have protection if the outlet was within 6 feet of a sink which by implication exempts outlets more than 6 feet from the sink.

and a glaring exception that I forgot to mention is for 240V appliances because the standard is applied to 125V outlets.

all of this suggests to me that there is a current (sorry) of thought that protecting grounded large appliances that aren't regularly moved around is marginally necessary or unnecessary or hews to a different standard the regularly accessed 125 V outlets in the subject areas,.

whether the vague nature of the exceptions for garages and basements made it reasonable to rethink them, I remain unconvinced the the code does, or if so that it does wisely, generally prescribe GFCI protection for major appliances.

Doesn't mean I think that is necessarily is a bad idea and I appreciate quick thoughts in post below on looking for stray water around electrical components and the motor is readily accessible from a rear panel on these washers so although i haven't observed any water leakage on the exterior of the appliance it is easy enough to leave the back panel off and run several loads and see if any leakage can be observed. I don't usually encounter leaks that are so minor as to not give some appearance on the floor or exterior surfaces but seems a reasonable enough course of inquiry

And as this very post points out experience transmitted to you from other professionals is that the trip time is 1/4 that allowed. As a practical matter that might be an industry habit to make sure that they stay under the time allowed, and you might have to pay more for a GFCI that went more precisely to that limit. Which leads me back to measuring the transients to see if that would be a practical solution of some nuisance trip circumstances. Back to the drawing board to figure out how to measure these transients with some kind of graphing ammeter in the ground line so I can see where we are relative to the standard.

Meantime I'm not 6 feet from a sink so until that occurs this remains an academic discussion. I still haven't had anyone respond to the question of why the standard should be the same for an installed grounded appliance as it is for circumstances where a person is much more likely path to be the only path to ground in the event of a fault? The code was one thing in 2005 another in 2008, maybe it is sensible for it to exhibit a third characteristic at some future date.

brian

 

[archibald tuttle]

The exceptions have been removed.

why did those specific exceptions which were obviously aimed at installed appliances exist to begin with? If I'm imagining things who imagined up those exceptions?

The timing and current levels are based on protecting people, increasing either defeats the purpose of the GFCI and is unneeded change as GFCIs work fine with equipment that is in good shape.

I have repeatedly asked those suggesting that these standards are set to protect people why the standard would be the same for circumstances where the person is likely to be the sole pathway for the fault than in circumstances where they are not? I can move the outlet to 6 feet away from a sink and leave the washer in the same place according to the code and forget about the GFCI. If my interest was meeting the letter of the law and getting on with life I wouldn't spend this amount of time and focus. I can almost always solve a problem by finding some way around the rock in the river but I tend to spend time trying to figure out why the rock is there and not to accept answers like 'to protect people' without digging into the entire range of costs and conveniences to providing that protection and weighing it against the level of risk. If you can tell me that the risk is the same with various portable electronics and installed grounded appliances I'm glad to weigh the evidence on that, but instead folks claiming a saftey motivation stick to the insistence that current above a certain level can be lethal without looking at the likelihood of a person being the sole ground to complete the fault.

in my opinion you seem hell bent on fixing a problem that does not exist.

that may well be, but it is the reason I want to measure the faults involved. maybe even though they are transient they are quite significant or quite lasting in which case I'll be glad to eat my words. It's happened before. It also could be that these faults are below the standard but still tripping the GFCI and then I would be interested in a unit that runs closer to the standard. And tracking them over time might give me some hint of what the problem is. This just cropped up during very humid weather and I'm wondering even if it could be related to doing cold washes/rinses during humid weather that is causing condensation to drip onto electrics. It comes and goes and would seem to defy easy repair. When you can simply move the plug a couple of feet and not require a GFCI, which if I am simply myopically reading the code isn't a band-aid it's a fix, I'm wondering if there may be some useful other option.

you say no without apparently considering this, or your proposal in consideration of it might be to change the code to 8 ft. or 10 ft. or 12 ft. whatever seems enough to deal with the people who went to 6 to get around this, when my proposal might be for a higher trip current for GFCI outlets serving solely a single grounded frame appliance which I argue, given the relative resistances involved, would provide similar safety to a 5 ma trip GFCI used with portable equipment without reliable frame ground. I think this could encouarge wider adoption of the technology including in locations that would have been exempt up through 2008 because how much turnover in existing installations has there really been since 2008 and might that be a way to encourage it?

brian