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Posted (edited)

Hi Electricity wizards,

 

I am getting a light shock via my aluminum-bodied lap top computer. This is not unusual nor dangerous, however, it is uncomfortable. I recently added an external monitor to the mix which can also power the computer via the USB-C input. But now the tingling via the computer is even worse. If I'm not mistaken, this happens because my house plugs are not grounded and so grounding is happening via the computer. Again, so I've read, not dangerous nor weird behavior for this lap top. I do have some hot water heaters in the house that ARE grounded, thank god. My question is, can I run a single ground wire from the plug where I power my computer and splice it into this ground wire that runs from the water heater to, of course, the ground? Could it be as simple as that?

 

Thank you, Bamboozled AND shocking.

Edited by bamboozled
Posted (edited)

yes any point that is grounded will work. you will know right away because the shocks stop. 

 

i had the same problem. very common. i got a 8' copper rod and drove it in the ground outside my window.

 

if you own the house you can drill a hole, but a flat braided wire will also work with a window. 

 

that is enough to stop the shocks. 

 

i used a large gauge wire from the ground rod to a AC power strip to ground every thing in my office.

 

this is very helpful in trouble shooting electrical wiring problems:

 

https://www.lazada.co.th//products/i1599650395-s4358518761.html?spm=a2o4m.cart.0.0.28d761088wa73g&urlFlag=true

Edited by NCC1701A
  • Like 2
Posted

I wouldn't be cutting and re-joining any ground wires but if you can tap in without then go for it.

 

Otherwise it doesn't need much of a ground to kill the tingle, even one of those generally useless 30cm rods would do the trick.

  • Like 1
Posted

Thanks all. ...Answers that I had hoped for. The wall outlets are not grounded for sure. I've been inside them plenty of times. I rent the house but it's a...fixer upper type...so if I drill a hole it will be lost in all the other holes. No problem there. There rods I can get at Home Pro/Global...hmm, or the local electric supply shop, I suppose.

 

Crossy, why wouldn't you splice into a ground wire? What's bad about that?

 

 

Thank you, Bam

  • Like 1
Posted (edited)
6 minutes ago, bamboozled said:

There rods I can get at Home Pro/Global

i saw them at Home Pro and Global House. The copper rod needs the little clamp thing for the wire. Sometimes sold separately. 

 

i bought a small sledge hammer for driving the rod in. 

 

and poured water to let the ground get softer. 

 

this is just for stopping the tingle. if you hit rocks at say 4' don't worry about it. 

Edited by NCC1701A
  • Like 2
Posted

Hello again electrical folk,

 

So, I have a 1 meter copper grounding pipe from global house with a screw at the top for securing the wire. Cost was about 300 baht. Now to start some pile-driving.

Posted
23 minutes ago, stubuzz said:

Is it normal for the copper coated grounding rods to rust?

No.  But they can and do corrode when environment is not friendly.

Posted (edited)
32 minutes ago, stubuzz said:

Is it normal for the copper coated grounding rods to rust?

 

Yes it's normal but undesirable. The rods aren't solid copper, they're copper clad steel. It's common practice to completely bury ground rods in concrete in Thailand but it's completely stupid, as there is then no way to later inspect the ground rod. You leave it sticking out of the ground, or in a ground pit, and then spray the connection with paint to keep the corrosion in check. Where they MUST be buried, they should be exothermically welded rather than clamped.

 

 

 

 

 

Edited by Led Lolly Yellow Lolly
Posted (edited)
On 6/3/2021 at 8:56 AM, NCC1701A said:

 

i had the same problem. very common. i got a 8' copper rod and drove it in the ground outside my window.

 

 

This works but you want to avoid driving multiple ground rods for individual devices/rooms if you can. You're creating a ground differential hazard (think lightning strikes nearby) which can cause huge damage or injury with galvanically separate ground points. Multiple ground rods where necessary should be bonded together. Grounding is a surprisingly complex topic.

 

 

 

 

 

 

 

 

Edited by Led Lolly Yellow Lolly
  • Like 1
Posted

Could you explain that, Lolly? How is it dangerous with lightning strikes if the grounds are all separate entities as opposed to linked?  What happens? Thanks!

Posted (edited)

Think about the advice given if you get caught in the open in an electrical storm, crouch down, hands on head, feet together. This is to avoid step potential, which could be tens or even hundreds of thousands of volts per metre as the lightning charge dissipates. This phenomenon radiates out across the ground for hundreds of metres from the point lightning hits the ground.

 

If you have multiple unbonded ground rods, the charge between rods will find a shorter less resistant path than the ground/soil (LAN cables, internal wiring etc etc). This will be the end of all your stuff.

 

 

 

 

 

Edited by Led Lolly Yellow Lolly
  • Like 2
Posted (edited)
47 minutes ago, bamboozled said:

Could you explain that, Lolly? How is it dangerous with lightning strikes if the grounds are all separate entities as opposed to linked?  What happens? Thanks!

As mentioned above, with a lightning strike there is an induced potential in the ground, this varies from the strike point. The difference in quite a short distance regularly  kills cows and sheep that are unlucky enough to face the wrong direction and be close enough for the potential to be high enough. 
 

So if you have multiple earth rods you will understand that it’s a bad, and just possibly, terminal idea. 

Edited by sometimewoodworker
  • Like 2
Posted

Okay, I sort of figured something like that. But my "logic" is telling me that if the rods are all linked together (perhaps I am misunderstanding "bonded"), when one gets tagged by the lighting, the current will then go through all of them instead of just one. Or perhaps the point was not only that the rods are linked but that they are all in the same spot.

This lightning strike thingy actually happened to me or rather to my stuff. There was a strike somewhere close by (not in Thailand) and it traveled through the wires and if I remember correctly shorted out the TV or the washing machine and I think the fridge. The same thing happened to some neighbors with different appliances. I think they said their TV turned on for an instant. My memory is foggy but what I DO remember distinctly is that the current traveled down the internet cable and melted the modem, as well as frying all the wires in the neighborhood. This was in the beginning days of wi-fi and lucky for me, I did NOT have my computer attached to the modem by cable at the time. Man, was I happy about that.

Posted (edited)

You misunderstood. The potential is very different in different places. It is the difference in potential that causes the problem. 
 

cow all 4 hooves standing on a 500kv potential = no problem, for the cow

 

cow with different potentials at each hoof = probably, lots of steak dinners.


distance required = very little (mm, cm, metres), but the greater the distance the higher the difference in potential 

 

The induced voltage in wiring is all part of the  phenomenon but is a realised rather than just potential, hence cooked electronics. 
Anyone for fried capacitor with baked microchips? ???? 

Edited by sometimewoodworker
  • Like 1
Posted

So one rod....only one chance of getting zapped. Multiple grounding rods, multiple chances of getting zapped, yes?

 

Alright, here come the flames... Well, I've got the ground bar in and a line running from it which I attached to the ground terminal in the 3 plug box where I'll be getting my power. I'm also running a 3-wire extension cord from that box since the plug is not near enough to the computer. But that should all be fine. What is annoying is that the computer monitor has a two-prong male plug coming from it with the ground wire coming out the top with a "U" type connector on it, presumptively to attach it to a grounded screw plug (why it didn't come with a 3-prong plug, I dunno). Well, I don't have the option of attaching it to a screw. Instead, I've jerry-rigged the set up that you see in the photo. Not pretty but is it dangerous at all? I don't think so but it's scary looking, sure. That wire running out of the box is, of course, attached to the ground terminal of the socket. I'm not getting a shock any longer from the computer. Well, certainly not as much of one. I still perhaps feel a tingling but I can't tell if its my imagination or not. If I am still getting a tingling (though much less of one than before), what does that tell us? My ground is not good enough?

IMG_3205.HEIC

Posted

I can't open your photo file. JPEG better if you could. 

Can you plug your computer and monitor separately? The monitor plug sounds like "Schuko". There are adapters for that to fit Western style but if you can plug separately, maybe not worry. 

  • Like 1
Posted

Sorry, guys. Damn iphone image. Here it is...

 

I can plug computer and monitor separately but the USB-C cable from computer to monitor also can provide power to the computer meaning I don't have to plug the computer in anymore thus just the one plug. I was getting a stronger shock when I had both plugged in though haven't tried it with my new contraption.

ground.jpg

Posted (edited)
2 hours ago, bamboozled said:

Sorry, guys. Damn iphone image.

Operator error not iPhone error 

 

Here's how.
  1. Go to Settings on your iPhone.
  2. Tap Camera. You will be shown some options like Formats, Grid, Preserve Settings, and Camera Mode.
  3. Tap Formats, and change the format from High Efficiency to Most Compatible.
  4. Now all your photos will be automatically saved as JPG instead of HEIC.
Edited by sometimewoodworker
  • Like 1
Posted

oh yeah, wonderful! I needed that...

26 minutes ago, sometimewoodworker said:

Operator error not iPhone error 

 

Here's how.
  1. Go to Settings on your iPhone.
  2. Tap Camera. You will be shown some options like Formats, Grid, Preserve Settings, and Camera Mode.
  3. Tap Formats, and change the format from High Efficiency to Most Compatible.
  4. Now all your photos will be automatically saved as JPG instead of HEIC.

 

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