List of all nuasance leakage tripping current sourcces of GFCI

[kwired]

Regarding Autotransformers, see if they comply with 210.9, 450.4, and 450.5.

Doesn't sound like code matters here. If it does, the question is which code, kind of hard to comply with NEC when you are mixing North American and European methods together, you usually need stick with one method or the other.

In my over 1,000 relatives and friends. I haven't heard of anyone getting a shock or electrocuted. I wonder if it's because our appliances are all plastic now. What metal chassis do you use regularly in the US? The reason there is such low fatality is the reason literally no one use any grounding around the country. All haven't heard of GFCIs too. I'm just doing it just to be sure and to learn fascinating new technology.

You mentioned a lab. So you may be in a high tech facility. Can you help me think of any commercially available open neutral service detector or possible design of one using combination of RCDs (see the url in the link below). I have a single 120v apparatus in a commercial building with neutral inside. And since the utility company doesn't maintain the service neutral well because not much use it. I don't want the electricity to divert to my aircon chassis or panel chassis if the neutral service gets open or disconnected. Please see this thread and help me. http://forums.mikeholt.com/showthread.php?t=195234

If there is no solution for a detector and disconnector in case of open neutral service. Then I need to remove the only 120v item in the commercial building which is the Siemens First Surge 140,000 Surge Protector Device. It has circuits inside it that uses 120v and may be more than 5mA. Please check out the link. Many thanks for the tips below. I'll think about it while waiting words from Siemens if my Siemens GFCI (the 16 to be installed) were counterfeit.

If you are complying with NEC and you have a grounded supply, you must bring the grounded conductor to the service disconnect or first disconnecting means for separately derived systems and bond all non current carrying metallic components of electrical system together to form the equipment grounding conductor. Even ungrounded systems where permitted must still have a grounding electrode and equipment grounding conductors - this to help assure equipotential between those items.

Just because you or your thousands of friends/relatives haven't been shocked doesn't mean it won't happen when something fails.

In a dwelling with wood subfloor and nonconductive finishes there isn't much to introduce "ground" potential so if an appliance frame does become energized there may not be much for shock hazard anyway. But bring something that is at ground potential near it and you will be shocked if you touch both at same time. This may be another appliance that is grounded somehow, a water pipe, concrete floor (especially if on grade), or outdoor outlets where you are on grade when using whatever is plugged into them.

 

[winnie]

If all appliances are insulated, then the risk of shock is greatly reduced.

in the US, many appliances have metal chassis; my fridge, my dishwashwasher, the clothes washer, etc. Most every large appliance has a metal chassis and a 3 wire plug with grounding.

-Jon

 

[tersh]

If all appliances are insulated, then the risk of shock is greatly reduced.

in the US, many appliances have metal chassis; my fridge, my dishwashwasher, the clothes washer, etc. Most every large appliance has a metal chassis and a 3 wire plug with grounding.

-Jon

Millions of households have this exact same setup. ​

​

I went to the back of my refrigerator to look at the ref model.. and I found the ground wire (it's in green/yellow) still unused. The main plug is 2 prong.

The main plug is about 2 sq mm (or 14 AWG when I looked at table). The ground wire is 18 AWG.

In situation like this. People don't know where to plug the green/yellow ground wire. Some who want to connect it use that on the cabinet, or faucet pipes (which won't trip the breakers). This is exactly the predicament of millions of other countrymen so all the time the ground wire not used because they don't know where to plug it. The outlets are only 2 hole. We know that it must eventually be plugged to the ground wire lug in the panel. But in most homes there is no ground lug.


What do you make of it?

All installers, licensed electricians, contractors, engineers, vendors just ignore it. As an engineer (I took engineering course 2 decades ago and reviewing lessons now). I have responsibility to give them advises that grounding is important and also to bring to the attention of code makers and government for some soul searching.

Are you familiar with Thailand. Since the refrigerators are made in Thailand (some in Vietnam and all others). Where do they plug their grounds? Is there any Thai engineers or electricians here?

 

[readydave8]

In my over 1,000 relatives and friends. I haven't heard of anyone getting a shock or electrocuted.

Anybody in that 1,000 that you haven't seen lately? Maybe it was them

 

[kwired]

Millions of households have this exact same setup. ​

​

I went to the back of my refrigerator to look at the ref model.. and I found the ground wire (it's in green/yellow) still unused. The main plug is 2 prong.

The main plug is about 2 sq mm (or 14 AWG when I looked at table). The ground wire is 18 AWG.

In situation like this. People don't know where to plug the green/yellow ground wire. Some who want to connect it use that on the cabinet, or faucet pipes (which won't trip the breakers). This is exactly the predicament of millions of other countrymen so all the time the ground wire not used because they don't know where to plug it. The outlets are only 2 hole. We know that it must eventually be plugged to the ground wire lug in the panel. But in most homes there is no ground lug.


What do you make of it?

All installers, licensed electricians, contractors, engineers, vendors just ignore it. As an engineer (I took engineering course 2 decades ago and reviewing lessons now). I have responsibility to give them advises that grounding is important and also to bring to the attention of code makers and government for some soul searching.

Are you familiar with Thailand. Since the refrigerators are made in Thailand (some in Vietnam and all others). Where do they plug their grounds? Is there any Thai engineers or electricians here?

What do instructions say to do with it?

Looks like a NEMA 1-15, which is intended to be used on nominal 120 volts, not sure why they wouldn't put on something intended to be used @ 240 volts on a 240 volt appliance unless it is not made to any listing standards.

Factory location doesn't really matter, they can make products intended for export that meet standards for where they are being exported to. They can also make products that do not meet any particular standard, buyer in those cases would likely give specifications when such standards are varied.

That unit shouldn't have valid listing for sale in the US, not saying it could never end up in US just that it doesn't meet listing standards. I also don't believe that there would be any listed for US that are not 120 volt units, at least for household grade units. Even commercial grade would be unlikely unless it is rated over ~1500 volt-amps, but such unit would be very inefficient or quite large.

 

[tersh]

What do instructions say to do with it?

Looks like a NEMA 1-15, which is intended to be used on nominal 120 volts, not sure why they wouldn't put on something intended to be used @ 240 volts on a 240 volt appliance unless it is not made to any listing standards.

Factory location doesn't really matter, they can make products intended for export that meet standards for where they are being exported to. They can also make products that do not meet any particular standard, buyer in those cases would likely give specifications when such standards are varied.

That unit shouldn't have valid listing for sale in the US, not saying it could never end up in US just that it doesn't meet listing standards. I also don't believe that there would be any listed for US that are not 120 volt units, at least for household grade units. Even commercial grade would be unlikely unless it is rated over ~1500 volt-amps, but such unit would be very inefficient or quite large.

This is the exact scenario:

Here is what the instructions say:

No. 5 says "To avoid possibility of electrical shock, ground the refrigerator properly. The earth screw is located on the rear side of the refrigerator."

All the walls in the millions of houses and commercial buldings have only this kind of outlet:

Now the main panels of millions of homes has no ground lugs:

So 100 million filipinos don't know how to use the ground wire. In this forum they discussed all ways to connect it.. it's funny.. they couldn't figure out how... https://www.philippines-expats.com/topic/29039-grounding-of-electric-appliances/

"

The OP asked what he should do with the ground wire from his Refrigerator. I mentioned that he should ground it to a water pipe, this is a safe and usual practice, not dangerous. One end of the wire is already grounded to the fridge, the free end to a grounding rod or water pipe as i was taught.​

"

Now to top it all of, the government don't care. All our inspectors are okay with 2 prong outlets and no ground. We copy from the US NEC every 10 years or so but all ignore it.

So how do you deal with this?

 

[kwired]

This is the exact scenario:

Here is what the instructions say:

No. 5 says "To avoid possibility of electrical shock, ground the refrigerator properly. The earth screw is located on the rear side of the refrigerator."

All the walls in the millions of houses and commercial buldings have only this kind of outlet:

Now the main panels of millions of homes has no ground lugs:

So 100 million filipinos don't know how to use the ground wire. In this forum they discussed all ways to connect it.. it's funny.. they couldn't figure out how... https://www.philippines-expats.com/topic/29039-grounding-of-electric-appliances/

"

The OP asked what he should do with the ground wire from his Refrigerator. I mentioned that he should ground it to a water pipe, this is a safe and usual practice, not dangerous. One end of the wire is already grounded to the fridge, the free end to a grounding rod or water pipe as i was taught.​

"

Now to top it all of, the government don't care. All our inspectors are okay with 2 prong outlets and no ground. We copy from the US NEC every 10 years or so but all ignore it.

So how do you deal with this?

If I had the answer to that I wouldn't need to work anymore, I think.

Makes some of the code disagreements we commonly have around here look like fairly ridiculous things to disagree about, and makes it look like you are stuck to some extent in what we had here in ~1940-1960 or so, though the grounded conductor at least was normally brought to service equipment.

When it comes to making laws, building codes and such are probably not that high of a priority, funding for AHJ departments is likely minimal, and therefore enforcement and further development of those departments never really progresses I would imagine. The rules are there because at some point it was deemed important to have such rules, but no money was spent to further develop any methods of enforcement or to keep up with evolving products, technologies and so forth.

 

[winnie]

Your situation is one that I do not envy.

Keep in mind that electrical codes are about _practical_ safeguarding; you will never have perfect safety with electrical installations.

"Practical" includes such issues as cost/benefit ratio, what sort of materials are actually available, maintainability, etc.

You are in a situation where the NEC is only partially followed, and you are trying to improve the safety of your home installation given what you can practically do.

You are dead certain that it is impractical to simply follow the NEC completely in your home. This would involve replacing the service drop to one which includes the neutral, replacing the feeder from the service drop to your home, replacing all of the wiring in your home, etc. I want to make it clear to you that such a replacement is certainly _possible_, but agree that given the context of how installations are done where you live it might be prohibitively expensive to actually do this.

If I had to deal with your situation, I would use GFCI protection for all branch circuits, and I would make sure that all non current carrying metal that someone could touch is bonded together. The reason for bonding is to eliminate potential difference between things that someone could touch.

For example, if someone could touch both the frame of the refrigerator and a metal water pipe, I would make sure that both are connected together so that there is no possibility of voltage between the two. If the floor is conductive (say concrete) I would bond to the rebar.

I would investigate any possibility of getting access to the service neutral; for example in the US the neutral wire is often a _bare_ wire that serves both as the neutral conductor and as mechanical support for the insulated wires; perhaps you actually have a neutral available that you've not recognized. It looks like your feeders are run in some sort of conduit; perhaps a neutral could be pulled without breaking concrete.

With no actual neutral load, the neutral conductor could be much smaller than the circuit conductors.

IMHO chasing an RCBO for the feeder is not really a good practical safeguard, but that is my gut feeling, not based on a detailed analysis.

In any case, good luck. I don't believe I have anything further to add to this discussion, but would appreciate learning how things turn out.

-Jon

 

[tersh]

A while ago. The microwave oven tripped on the local 240v meiji GFCI receptable (without UL auto main self test). I tried to look at the back of the microwave oven (picture above). I couldn't find any grounding wire or even connector and it's pure metal frame. If I sandpaper a part and insert in the screw, it can void the warrantee.

The microwave oven is beside the refrigerator (specs and manual shown earlier). If I put EGC (Equipment Grounding Conductor) to the refrigerator while I can't put one in the microwave oven. What if the person touch the microwave with hot line touching the metal chassis and the person touches the refrigerator too (with EGC). The refrigerator can serve as large return current source for the leaking microwave shocking the person or worse.

I can't find a single metallic chassis in the country with EGC. Is there any provision elsewhere that said all the appliances either need to have EGC or none at all (to avoid the scenario above where one appliance (microwave) without EGC can make complete path to the refrigerator with EGC?) Maybe my country follows this rule that is why not a single appliance with metal chassis have any EGC level grounding?
​

 

[Adamjamma]

First off, I am surprised the microwave did not actually cause more problems if it has not been modified somehow because the tag on it specifically says it is a 120 volt unit.. yet you have been telling is everything there is set for 240 volts... so you should be importing devices from the European markets or other 230 or 240 volt markets.

 

[tersh]

First off, I am surprised the microwave did not actually cause more problems if it has not been modified somehow because the tag on it specifically says it is a 120 volt unit.. yet you have been telling is everything there is set for 240 volts... so you should be importing devices from the European markets or other 230 or 240 volt markets.

It's 220v, not 120v.. here's the zoomed in of the tag. We have a thousand appliance centers in the country and all appliances are 240v only (even lamps). No home user import it themselves.

 

[tersh]

It's 220v, not 120v.. here's the zoomed in of the tag. We have a thousand appliance centers in the country and all appliances are 240v only (even lamps). No home user import it themselves.

Anyway. Can anyone give list of countries with appliances that don't have any grounding (like the microwave oven above, etc.)?
Is grounding only strictly followed in the USA, UK, Israel and perhaps none at all in China, Africa, Asia? And can anyone give statistics about electrocution from those appliances. Hasn't there any study about this?

 

[kwired]

We had this sort of problem back in 1940's - 1960's. It took some time to get rid of a majority of such appliances, but you still run into some here and there. Today they have a equipment ground in the supply cord or are "double insulated" (or they likely are not listed by an NRTL).

 

[Adamjamma]

ok, stand corrected. Still, if you are concerned about grounding it, loosen a case screw, attach a green cable, and run the cable to a bonding point that will continue the connections to the main EGC...

If you have had no problems then leave it alone as it has worked so far... might be ok, might not be...

Problem is, there are too many variables. Right now in Europe and USA we have everyone knee jerking because of some fires and insisting upon Arc Fault Breakers but every paper I have read that has studied the phenomenon of fires caused by arc faults and the breakers themselves has said that most fires are not actually caught by the arc fault breakers and they are more nuisance than anything else. Apparently, a small heat detector circuit of some sort inside each outlet box would be of more use than an AFCI breaker.

So, more for you to look into as you continue your studies.