I’m feeling a strange hum or light tingling feeling on my skin when I touch my computers

[KKr]

13 hours ago, cooked said:

Thai solution: remove the power plug and turn it round. 

Installing an earth connection is obviously the best solution, but in most houses this means buying new plugs and rewiring. 

changing the neutral and life, i.e. turning the plug upside down worked for me as well.

[TKDfella]

Ha, this was the first thing I noticed when I came to Thailand on a visit, two pin sockets. I later enquired about the grounding when I came to live and found that basically it was inadequate. When my Thai wife wanted a microwave oven the instructions clearly strongly advised grounding and in fact the guarantee was null and void without it. So I asked the 'local electrician' to install the unit and 'earth' it properly. I had a couple of other sockets altered also...all unnecessary according to the electrician, ha!

[Monkeyrobot]

Some houses and condos don’t even have a ground connection. All the cabling is just two core, active / neutral, that’s ok for lights but not for power points / ac / water heaters/ stoves, I would call an electrician to have a look at your power box. 

[Bruce404]

As others above have commented, that tingling sensation you get indicates that the appliance (computer, refrigerator, printer, etc.) is not properly grounded/earthed.  Some tiny amount of current is leaking into the metal frame of the appliance.  The tingling might be more severe (even deadly?) if you touch the appliance without wearing shoes on a wet floor.

 

Even if the large white ground ("earth") wire connected to the rod in the soil outside the house (as shown in your pictures) is working, somewhere between the appliance and that grounding rod might be some interruption that blocks the wayward current from escaping safely. 

 

For example, as mentioned by another above, the power strip may lack a third ground/earth plug into the wall ("mains") outlet, even if the strip has three holes for each tap.  Or the wall outlet(s) is(are) not wired with a proper ground wire back to your circuit-breaker box, even though there are three holes to plug into.

 

The easiest way to check all this is to obtain an electrical outlet tester, two examples of which are shown in the attached images.  I have the yellow, Sperry brand one.  Although purchased in the USA and labelled only for 125 volts AC, I took a chance and it works fine on Thailand voltage of 220-240.  Each has three colored lights, which indicates if the wiring is hooked up correctly or wrongly.  In your case, if the ground/earth wire is not connected, it should indicate so.  Trying to test whether the ground rod outside itself is working is trickier.  

 

Perhaps one can pick up such an outlet tester at HomePro, Global House, or other "big-box" hardware stores, or certainly at specialty electrical supply and tool shops.  https://www.Lazada.co.th has several upon using the search term "outlet tester".  Even if shipped from China, in my experience items from Lazada conveniently and reliably arrive within 10 days to 2 weeks, often with free shipping.  Just make sure that the one you order has three prongs and matches the openings in your wall outlets (i.e., avoid the British and some Euro versions).

 

For those in high-rise condos where ground wires are lacking in wall outlets, one way to access a ground/earth might be to guess (or use a "Bosch wall scanner", or equivalent device that can tell you) where steel rebar may lie in an out-of-the-way closet wall.  After knocking out a bit of overlying  brick or concrete, that steel likely has enough linkages to other steel throughout the building to carry current to the soil below the building, and thus serve as a poor-man's surrogate ground/earth terminal.

 

Edited May 10, 2019 by Bruce404

[xtrnuno41]

On 5/8/2019 at 12:32 PM, MrScratch said:

Ok, so I thought I would try this , unplug the HDMI lead from the external monitor that was connected to my laptop ( and still making my hand tingle ) and use my multimeter set to AC volts , then put one multimeter probe into an Earth connection on a wall socket and the other multimeter probe onto to the metal part of the HDMI plug . this is what I get ????

 

 

It shows your ground isnt really working. The resistance is too high, any leakage should run away by ground. Thats is why you have the groundrod.

You have a problem with a device, not necessarily a computer. As all grounds are connected, you can have a problem with like the water heater (shower), refrigerator or any device connected to an earth socket or the ground. The leakage spread to all devices on ground and not to rod, as rod resistance is too high. 

Find the device with the problem. Detach all which are on ground and see then when it stops. Careful as all devices with ground should be with the 98 volts.

You measured on the ground of the HDMI, so its every where.

 

Or maybe just a wire, you took out all devices and it is still there, a live one is on the wrong position, on earth, then of course you have to change position.

If the soil, in which the rod is, is wet then you have less problems, but if soil gets dry you get more problems.

 

Your heart can not have much Amps, its up to 0.03 A.

Now you touched it and get a tinkling, already a warning, you just have enough resistance to keep it at a tinkling. If you squeeze it, then it could be fatal.

All depending on your personal condition, like heart condition, if you sweat, if you eat salty food. 

Also power is up to 50 Volts AC or 120 volts DC, to be said "safe".

Therefor im more charmed with mechanical RCBO's, if there is a difference between in and out on the wiring to the group in mA, it shuts down at 30 mA. They can be added to fuse groups, aswell there are fuses including this device, so then every group has a RCBO.

Electricity can kill you easy, if you survive , you are lucky.

Be careful with it and fix it. Otherwise just one day, you or someone with you will die.

 

[Bruce404]

By the way, I had the same tingling on a new SONY TV used as an extended monitor for a laptop.  So I found an accessible screw on the back of the TV/monitor and ran a copper wire from it to a round, metal object about the same width as a spare ground/earth hole on the power strip.  Upon plugging it in to the spare grounding hole on the power strip -- Voila!  That shunted the stray current to ground and the tingling stopped on the monitor.  

 

On the other hand, the 98 volts that you measured is quite dangerous, and suggests you have a more serious problem,  Perhaps, as someone suggested earlier, there is a reversed connection between line/hot and earth or neutral somewhere in your house, and the ground rod cannot shunt it all safely to the soil.  But such a mistaken connection ought to trigger the corresponding circuit breaker to trip.  Why it has not is worrisome.  Get a pro to check out your wiring (and wear rubber shoes around the house in the meantime).

Edited May 10, 2019 by Bruce404

[SailingHome]

Hi. Sorry I took so long to find this. As a doctorate holder in electrical engineering and other things, I immediately diagnosed this when I moved here 9 years ago and had my building owner install a ground. He was so glad I solved his problem.

Inside of my room, however, I still have some shocks. They are because of my wife sneaking in an un-grounded  power strip or a bad appliance that leaks current to neutral. 

This isn't ONLY a grounding issue. When power leaks to neutral you have a higher energy bill and more tingles.

 

Chat me up if you want some help solving it without the owner.

[Crossy]

8 hours ago, SailingHome said:

They are because of my wife sneaking in an un-grounded  power strip or a bad appliance that leaks current to neutral. 

 

I understand the ungrounded power strip issue (mains filter capacitors). 

 

But the "leak to neutral" how does that cause a tingle, surely it's just another load and there should be no path to the casework?

 

[Uptooyoo]

Be very careful in Thailand. Have your system inspected. I moved into a condo and found several grounding issues. When I was working on the balcony, I brushed my arm along the air-conditioning unit and received a shock. I am a licensed electrician, so I have a Digital VOM I carry and measured the frame to earth voltage. It was 93 volts. I turned off the breakers and opened the connection box. None of the ground wires were connected, nor were the ground wires going to the fan units inside. At least the green wires were there, so I was able to make the connections myself. I checked again and the frame to earth voltage is now less than two volts. I found an issue with the refrigerator too: I measured 73 volts from the frame to earth. It is common for the manufacturer to install an internal bonding connection from the earthed "neutral" conductor to the frame. The problem is that in Thailand receptacles may not be polarized, therefore allowing you to reverse the plug and apply the "hot" side of the receptacle to the frame of the refrigerator. Very dangerous.  A temporary solution is to reverse the plug to ensure the neutral side of the plug is connected to the neutral wire in the refrigerator. I told my girlfriend to never plug in any appliances until I check polarity first. This is but one issue causing so many tourists to go home in body-bags.

 

Edited May 28, 2019 by Uptooyoo
clarification

[bankruatsteve]

1 hour ago, Uptooyoo said:

It is common for the manufacturer to install an internal bonding connection from the earthed "neutral" conductor to the frame. The problem is that in Thailand receptacles may not be polarized, therefore allowing you to reverse the plug and apply the "hot" side of the receptacle to the frame of the refrigerator. Very dangerous.  A temporary solution is to reverse the plug to ensure the neutral side of the plug is connected to the neutral wire in the refrigerator. I told my girlfriend to never plug in any appliances until I check polarity first. This is but one issue causing so many tourists to go home in body-bags.

 

Not sure where you get your information but I'm responding because the facts as I know them differ.  It is not common (perhaps non-existent) for mfg to bond neutral to the frame.  Any 2-pin receptacle will have L on one pin and N on the other (so they are "polarized").  If an appliance provides only a 2-pin plug then it shouldn't make any difference how it is positioned.  Class-1 appliance must be connected to ground - when properly done, they will never be lethal.

[Uptooyoo]

21 minutes ago, bankruatsteve said:

Not sure where you get your information but I'm responding because the facts as I know them differ.  It is not common (perhaps non-existent) for mfg to bond neutral to the frame.  Any 2-pin receptacle will have L on one pin and N on the other (so they are "polarized").  If an appliance provides only a 2-pin plug then it shouldn't make any difference how it is positioned.  Class-1 appliance must be connected to ground - when properly done, they will never be lethal.

My refrigerator has only two pins, my receptacle has three, and I can plug it in either way. I went to HomePro and all the refrigerators had two-pin plugs. I don't care how it's labeled; if you can physically reverse the plug, it is not polarized.  I attached a picture with the plug reversed...183.6 volts. Would you care to come over and submerge your hand in my sink and touch the fridge???

Edited May 28, 2019 by Uptooyoo
clarification

[bankruatsteve]

11 minutes ago, Uptooyoo said:

My refrigerator has only two pins, my receptacle has three, and I can plug it in either way. I went to HomePro and all the refrigerators had two-pin plugs. I don't care how it's labeled, if you can physically reverse the plug, it is not polarized. 

Well, you were first talking about the receptacle.  In Thailand, at least, most receptacles are polarized but most plugs are not.  If you can physically reverse the plug, I agree, it is not polarized.  But, in that case, it shouldn't make any difference.

[Uptooyoo]

9 minutes ago, bankruatsteve said:

Well, you were first talking about the receptacle.  In Thailand, at least, most receptacles are polarized but most plugs are not.  If you can physically reverse the plug, I agree, it is not polarized.  But, in that case, it shouldn't make any difference.

It does make a difference. That's why in the U.S. the neutral blade is wider so the plug can't be reversed. In addition to safety concerns, many electronic devices are polarity sensitive and require that the neutral stays at ground potential.   

Edited May 28, 2019 by Uptooyoo
clarification

[bankruatsteve]

7 minutes ago, Uptooyoo said:

It does make a difference. That's why in the U.S. the neutral blade is wider so the plug can't be reversed. In addition to safety concerns, many electronic devices are polarity sensitive and require that the neutral stays at ground potential.   

OK OK.  All I am saying is, if the plug is not polarized then, for the appliance it is connected to, it should not make any difference.

[Uptooyoo]

24 minutes ago, bankruatsteve said:

OK OK.  All I am saying is, if the plug is not polarized then, for the appliance it is connected to, it should not make any difference.

Yes, absolutely. It does not affect the functionality of the refrigerator. But from a safety standpoint, it should have a three-prong plug. A Hot, a Neutral, and a ground attaching directly to any exposed metal surfaces that can become inadvertently energized, e.g. ground fault. As I said I went to HomePro and all of them had two prong, which means no hard ground to the frame. Why they don't use three prong plugs on refrigerators, when the rest of the world does, I just don't understand. Maybe some other readers can add to this topic. 

 

Edited May 28, 2019 by Uptooyoo
clarification

[bankruatsteve]

11 minutes ago, Uptooyoo said:

Yes, absolutely. It does not affect the functionality of the refrigerator. But from a safety standpoint, it should have a three-prong plug. A Hot, a Neutral, and a ground attaching directly to any exposed metal surfaces that can become inadvertently energized, e.g. ground fault. As I said I went to HomePro and all of them had two prong, which means no hard ground to the frame. Why they don't use three prong plugs on refrigerators, when the rest of the world does, I just don't understand. Maybe some other readers can add to this topic. 

 

I don't know for sure but it could be the case where the refrigerators are Class-2 these days. (?) My 3 year old Samsung "inverter" does have a 3-prong plug.  My old Hitachi had a non-polarized 2-prong plug along with a ground wire that you are supposed to connect to ground.  (Thai sparks drill a hole in the floor)

 

The point is, if the mfg does not provide a polarized plug then they are either negligent OR it just doesn't matter for the design.  Hopefully, it is not the former.

 

[Crossy]

4 minutes ago, bankruatsteve said:

Hopefully, it is not the former.

 

Sadly, in many cases here it's this ????

 

Both our freezer and fridge-freezer are Class-1 with 2-pin plugs, they have a terminal on the back which is supposed to be earthed. Neither is particularly old or from weird unknown manufacturers.

 

Of course we add in to the mix the European Schuko plug which a lot of kit used to come with and we have a recipe for zappo!

 

 

 

[kekalot]

I'm about to move to a different place.. ground is one of the things I check when i visit places for rent.

 

in my case, not so worried about small appliances  not having ground as I can just unplug them but I will likely have to get a new fridge and would prefer it to be grounded,  it blows my mine that something that big wouldn't have a ground.

 

should I even bother to go look for a fridge that has a ground plug or is that a fools errand?  (doesn't have to be a 2019 model, maybe older years but still new are a better choice in this case?)

 

 

 

[Crossy]

20 minutes ago, kekalot said:

should I even bother to go look for a fridge that has a ground plug or is that a fools errand?  (doesn't have to be a 2019 model, maybe older years but still new are a better choice in this case?)

 

It certainly can't hurt to look. But even if you don't find one it's not rocket science to run a wire from the metalwork to the 3rd pin of your outlet.

 

[MrScratch]

Just an update 

 

First a Big thank you to every one for your kind help and advice .

 

 

I placed an order for an outlet tester ( coming from abroad ) in the mean time I decided to replace the old Earth rod with a new longer one.  Once I had replace the Earth rod the problem with the voltage  0.98 V AC , between the HDMI and an Earth connection instantly disappeared .

 
Then the outlet tester finally arrived so I plugged it into a house mains wall socket , but looking at the instructions that came with the outlet tester , the correct ‘’ no problems detected ‘’ indication should show only 2 red LED lights lit so LED no. 3 far right should not be on.

 

When I tested all my house mains wall sockets , both LED’s No. 1 and 2 were brightly lit , but LED no. 3 ( which should not be lit ) was glowing slightly .

 

the photograph shows the outlet tester plugged into a house wall socket , and the No.3 red LED glowing slightly.

 

I’m not sure what is going on and what it means if LED No. 3 is glowing slightly .

Any one have an idea ?

 

[Crossy]

11 minutes ago, MrScratch said:

Any one have an idea ?

 

Are you sure the outlet you are plugged in to is correctly wired? If so then a glow from the 3rd LED probably means nothing.

 

There are not many of these testers that will work correctly in Thailand unfortunately. Since you got it on-line could you post a link to the advert please.

 

 

[Bruce404]

In a previous post of mine on this thread, I had read the original poster's photograph of his voltage meter as reporting "98" (i.e., 98.0) volts (no decimal point was visible in the meter's screen, and the dial was pointing to the appropriate 500v AC range), which prompted my warning.  Now I read it was really just 0.98 volts, a big difference!

 

As Crossy points out, the slight glow of the right-most LED is probably insignificant and can be ignored -- once you have looked inside the wall outlet to verify the colored wires are going to the right terminals.

 

Perhaps one needs a tester of the KKMoon ("KKM5 socket tester") outlet tester, which may have some slight internal leakage into its right-most LED! ????

Edited June 3, 2019 by Bruce404

[MrScratch]

3 hours ago, Crossy said:

 

Are you sure the outlet you are plugged in to is correctly wired? If so then a glow from the 3rd LED probably means nothing.

 

There are not many of these testers that will work correctly in Thailand unfortunately. Since you got it on-line could you post a link to the advert please.

 

 

Ive looked at the back of the outlet and it seems to be correct , I'm going to go around the house and look in the back of all the wall socket outlets .

 

I purchased the outlet tester from here 

 

https://www.lazada.co.th/-i281771851-s458319764.html?urlFlag=true&mp=1&spm=spm=a2o4m.order_details.item_title.1

 

 

 

 

 

[MrScratch]

2 hours ago, Bruce404 said:

In a previous post of mine on this thread, I had read the original poster's photograph of his voltage meter as reporting "98" (i.e., 98.0) volts (no decimal point was visible in the meter's screen, and the dial was pointing to the appropriate 500v AC range), which prompted my warning.  Now I read it was really just 0.98 volts, a big difference!

 

As Crossy points out, the slight glow of the right-most LED is probably insignificant and can be ignored -- once you have looked inside the wall outlet to verify the colored wires are going to the right terminals.

 

Perhaps one needs a tester of the KKMoon ("KKM5 socket tester") outlet tester, which may have some slight internal leakage into its right-most LED! ????

Sorry my mistake 

 

It was 98V AC

 

 

 

 

 

 

[Bruce404]

Another explanation for that slight glow in the right-most LED of your new KKMoon Socket Tester is not what I suggested earlier as perhaps a [minute electrical] leakage into that LED.

 

It is more likely that the three LEDs are not "photonically" shielded from each other within the device.  In other words, light, not electrons, is leaking from the middle LED to illuminate the right-most one.

 

You can safely ignore the slight glow.

[MrScratch]

On 6/3/2019 at 8:01 PM, Bruce404 said:

Another explanation for that slight glow in the right-most LED of your new KKMoon Socket Tester is not what I suggested earlier as perhaps a [minute electrical] leakage into that LED.

 

It is more likely that the three LEDs are not "photonically" shielded from each other within the device.  In other words, light, not electrons, is leaking from the middle LED to illuminate the right-most one.

 

You can safely ignore the slight glow.

Appreciate the advice ????

 

 

 

 

 

 

 

[mrwebb8825]

For condos/apartments; buy some inexpensive rubber mats and place them where your feet would be when coming in contact with computers and appliances so you're not grounded when you touch them. Might also buy a better HDMI cable to eliminate the hum.

[Crossy]

1 hour ago, mrwebb8825 said:

For condos/apartments; buy some inexpensive rubber mats and place them where your feet would be when coming in contact with computers and appliances so you're not grounded when you touch them. Might also buy a better HDMI cable to eliminate the hum.

 

Hmmm, interesting concept somewhat akin to treating a broken leg with aspirin. Don't treat the symptom (the tingle), treat the cause (no ground).

 

Desperate? Why not try the plant-pot ground?

Check my comments in posts #13 and #15.

 

[Uptooyoo]

My concern is when I read that Thai "sparkys" drill a hole in the floor to ground appliances rather than connect to the ground pin at the outlet. If the appliance is attached to an earth-only connection, say, to the concrete floor or to a separate ground rod, the resistance will be too high to trip the breaker because the fault-current (hot wire touching the metal frame of an appliance) will be forced to travel through the physical earth and then up the ground rod at the transformer to complete the circuit; not enough current will flow to trip the breaker and the appliance will remain energized with a potentially lethal voltage on exposed surfaces. If the appliance is connected to the ground pin at the receptacle; however, a low resistance path is created back to the source, which is usually a pole-mounted transformer. The fault-current travel path is not through the earth; it is through the green ground-wire back to the panel, and from there, through the neutral wire back to the transformer. This path has very low resistance, allowing many hundreds of amps to flow. The breaker will trip in milliseconds, thereby de-energizing the appliance.

Edited June 7, 2019 by Uptooyoo
clarification

[Bruce404]

    I think "UpToYoo" has a mistaken understanding of what residual current devices (RCDs), residual circuit breakers with overcurrent protection (RCBOs), and Ground Fault Circuit Interrupters (GFCIs, as termed in the USA) do and how they work. 

    It has nothing to do with leaking current going down a makeshift ground directly from the frame of an appliance, through the earth and retrograde from the formal grounding rod back up to the electrical panel/circuit board.

    Essentially the RCDs, RCBOs, and GFCIs measure both the currents "flowing out" on the Line ("hot") wire to an individual circuit and the Neutral wire "returning from" that circuit.  If they differ by more than a safe amount, the devices assume some of the current may be passing unsafely through a human being or pet, and immediately break the circuit to stop any electrocution.  

    Quotes are used around "flowing out" and "returning from", as for alternating current (AC), the electrons are actually changing direction to go back and forth either 50 or 60 times per second (Hertz = Hz) , depending on where in the world one's electrical supply is being generated.  Think of it like the Line wire is a straw with air like the electrical current:  the power company is quickly blowing air out and sucking air in on just the Line, and changing direction 50 or 60 times a second.  When an appliance or light is on, that "air" flows all the way to and from the planet earth below the house.  That's why one can safely touch a Neutral wire properly hooked up if the appliance or light is off.  But not ever a Line wire.

 

Edited June 7, 2019 by Bruce404