Using earthed computer cord with unearthed power outlet

[george]

Hello in the Electric Forum!

 

I get smaller electrical shocks when touching my computer at another location than home. The power outlets provided is "Thai standard" un-earthed:

 

My computer (Apple) has this power cord.

 

It's very uncomfortable with the small shocks I get. (tried alredy with a un-earthed "Thai" extension cord).

 

What do I do? (I am not able to change the outlets at this location.)

I could cut the third prong on this connector, but doesn't 

 

If I install an UPS (un-earthed) would this help?

 

Any easier solution?

 

Please advise 🙏🏼

[Muhendis]

The small electric shocks will be from the computer power supply.

These normally require earth connection too an electronic filter.

If there is no grounded case then the filter will discharge into anything which touches the case ie you.

Fixing this depends on if there is a local ground anywhere near the computer.

If there is, then a wire connected between computer case and ground will stop the "tickle" you get from the case. 

Edited October 30, 2023 by Muhendis

[Lemsta69]

Sounds like you need @Crossy to pay you a visit and rewire the place.

[george]

7 minutes ago, Muhendis said:

The small electric shocks will be from the computer power supply.

These normally require earth connection too an electronic filter.

If there is no grounded case then the filter will discharge into anything which touches the case ie you.

Fixing this depends on if there is a local ground anywhere near the computer.

If there is, then a wire connected between computer case and ground will stop the "tickle" you get from the case. 

Thanks! There is a local ground anywhere near the computer.

[Crossy]

@george

 

Your PC needs a "functional earth".

 

Any way to get a connection to the "earth", a short rod in a flower bed outside the window? A metal water pipe or balcony railing? It doesn't need to be a very good earth.

 

Otherwise just keep your Crocs on 🙂 

[TimeMachine]

I'm curious. Is there earth leakage safety cut breakers at the location? The breakers that have the push button on them.

[george]

Just now, TimeMachine said:

I'm curious. Is there earth leakage safety cut breakers at the location? The breakers that have the push button on them.

No.

[Crossy]

1 minute ago, TimeMachine said:

I'm curious. Is there earth leakage safety cut breakers at the location? The breakers that have the push button on them.

 

The amount of leakage concerned here would be way too small to operate an RCD/RCBO although having one would enhance the general safety of the electrics.

 

[TimeMachine]

10 minutes ago, Crossy said:

 

The amount of leakage concerned here would be way too small to operate an RCD/RCBO although having one would enhance the general safety of the electrics.

 

Yeah. It's concerning if any chassis should pass current to you. If the resistance of the path from live to chassis should decrease then it gets dangerous without knowing the leakage path. I've got a convection style microwave that zaps me a bit. I know the element is the cause and I have rcbo so I know I won't die. But this chap should get the appliance grounded or rcbo. Keep safe chaps.

Edited October 30, 2023 by TimeMachine

[Crossy]

3 minutes ago, TimeMachine said:

Yeah. It's concerning if any chassis should pass current to you. If the resistance of the path from live to chassis should decrease then it gets dangerous without knowing the leakage path. I've got a convection style microwave that zaps me a bit. I know the element is the cause and I have rcbo so I know I won't die. But this chap should get the appliance grounded or rcbo. Keep safe chaps.

 

In this case we do know the leakage path, it's the mains inlet filter that keeps the nasties from the switching power supply from getting into the wide world, hence the usage of the term "functional earth" it's needed for the device function correctly rather than safety.

 

 

[Screaming]

You know you are living in a third world country when the outlets do not provide a ground. It's all part of Thainess. Life is cheap in Thailand.

[OneMoreFarang]

1 hour ago, george said:

If I install an UPS (un-earthed) would this help?

 

Any easier solution?

No

Accept reality (in Thailand).

[VocalNeal]

2 hours ago, george said:

I get smaller electrical shocks when touching my computer

 

Then don't touch it🤔 

[carlyai]

@george 

If you have an instant water heater, have a look how the earth wire (should be a green coloured wire) is connected. See if it runs outside to an earth rod knocked in the ground.

You could do the same near the computer. Knock an earth rod in the ground near the computer and connect a wire from it to the computer schassis.

[TimeMachine]

1 hour ago, Crossy said:

 

In this case we do know the leakage path, it's the mains inlet filter that keeps the nasties from the switching power supply from getting into the wide world, hence the usage of the term "functional earth" it's needed for the device function correctly rather than safety.

 

 

Why not a leaky capacitor that's failed or a frayed burnt cable leaning up against the case? Has the chap opened the casing to check and make sure?

[Crossy]

9 minutes ago, TimeMachine said:

Why not a leaky capacitor that's failed or a frayed burnt cable leaning up against the case? Has the chap opened the casing to check and make sure?

 

OK, let's say that the balance of probability is that it's just leakage via the mains filter. 

 

What is YOUR solution??

 

[george]

8 minutes ago, TimeMachine said:

Why not a leaky capacitor that's failed or a frayed burnt cable leaning up against the case? Has the chap opened the casing to check and make sure?

No, this chap hasn't opened this iMac to check. 

[Crossy]

6 minutes ago, george said:

No, this chap hasn't opened this iMac to check. 

 

And this chap recommends that you don't 🙂 

 

Have you managed to locate anything that could serve as a make-shift ground?

 

[george]

Just now, Crossy said:

 

And this chap recommends that you don't 🙂 

 

Have you managed to locate anything that could serve as a make-shift ground?

 

One thing: The water heater in the bathroom has an earth cable, will try to locate the rod outside, if any. 

[Crossy]

I'm not sure if anyone has suggested this, but since you have a 2-pin plug in the wall try just reversing it in the outlet.

 

[george]

2 minutes ago, Crossy said:

I'm not sure if anyone has suggested this, but since you have a 2-pin plug in the wall try just reversing it in the outlet.

 

Will try that as well!

[patman30]

5 minutes ago, george said:

One thing: The water heater in the bathroom has an earth cable, will try to locate the rod outside, if any. 

rods are cheap, if you cannot find from the water heater
just grab one and some cable and make your own earthed power strip
PITA i know but solves your problem

[TimeMachine]

17 minutes ago, Crossy said:

 

OK, let's say that the balance of probability is that it's just leakage via the mains filter. 

 

What is YOUR solution??

 

That's why I mention rcbo. If the problem is ignored and it is a more dangerous issue with rcbo installed  the chap lives. Otherwise, open the chassis and investigate because unlucky as it seems if it's a problem that can leak more voltage at the chassis to pass more current through the body the chap could kark it in their  pants.

[Crossy]

PC power supplies, moreso those from brand names, are very safe, I don't recall ever seeing one fail in a way that would be actually hazardous, of course that doesn't mean it's never happened. 

 

IMHO the risks of an unskilled person opening up the mains section of a PC far outweigh the possibility of an actual internal fault.

 

On an Apple product is it even possible to open the power supply?

 

[Muhendis]

4 hours ago, Crossy said:

 

The amount of leakage concerned here would be way too small to operate an RCD/RCBO although having one would enhance the general safety of the electrics.

 

The main job of this computer power supply filter is to prevent spikey bits of high frequency switching, which are generated by the computer power supply, from getting into the mains wiring. If that happens too much then there could be interference problems in other gadgets plugged in to the same supply. This means that the shocking feeling is more likely to be high frequency rather than mains voltage although both are likely to be present.

[sometimewoodworker]

5 hours ago, Crossy said:

On an Apple product is it even possible to open the power supply?

It very much depends on the particular product and your enthusiasm for dissection, the more expensive the product the more likely that you maybe able to get to the power supply, disassemble it, and return it to working order. 
 

However in the many Apple computers I’ve had and been given and worked on I have never experienced a problem with the power supply, Apple engineering of the PSU is just too good.

Edited October 30, 2023 by sometimewoodworker

[Dan O]

6 hours ago, patman30 said:

rods are cheap, if you cannot find from the water heater
just grab one and some cable and make your own earthed power strip
PITA i know but solves your problem

Several years ago before I rewired the house a local the wife knew installed a replacement tankless water heater in the bath while I was away. When I got back I was pleased to see a nice fat ground wire run over the exterior wall to the area the main ground rod was on the other side of the wall. When I checked outside the ground wire was about 1/2 meter short of reaching the rod and just pointed up in the air.  I fixed it with a new wire and later when I saw the local I asked him about why he didn't fix it and connect the ground wire. He looked at me kinda puzzled and said "oh Its ok and works fine"  I asked him how it could and with a straight serious face he explained it works just like wifi signal thru the air.  

[TimeMachine]

All things considered above. The different actions explained by all are warranted. Using a device that zaps you may feel like a fun novelty at the time. But if no remedies are found I would not suggest just keep using the device as it is. Unless death is just an accepted albeit unlikely option.

1.sort out Earthing.

2.install RCBO breaker in switchboard or atleast plug in rcbo adapter.

3.remedy device so it doesn't zap.

One of the above.

My preference is rcbo. 

 

 

 

 

[carlyai]

1 hour ago, TimeMachine said:

All things considered above. The different actions explained by all are warranted. Using a device that zaps you may feel like a fun novelty at the time. But if no remedies are found I would not suggest just keep using the device as it is. Unless death is just an accepted albeit unlikely option.

1.sort out Earthing.

2.install RCBO breaker in switchboard or atleast plug in rcbo adapter.

3.remedy device so it doesn't zap.

One of the above.

My preference is rcbo. 

 

 

 

 

In this case I can't see how an RCBO will stop the tingle from the computer schassis.

As Crossy said, keeping your Croks on will do it. 

Also earthing the computer schassis.

Maybe reversing the plug or installing an isolating transformer also.

[TimeMachine]

9 minutes ago, carlyai said:

In this case I can't see how an RCBO will stop the tingle from the computer schassis.

As Crossy said, keeping your Croks on will do it. 

Also earthing the computer schassis.

Maybe reversing the plug or installing an isolating transformer also.

It won't stop the tingle it will stop the deadly current if the problem gets to be a heavier current. If you can guarantee it stays at a tingle then that's not a problem. Add crocs to the list.