Electric Shocks From Computer Equipment

[JetsetBkk]

Not read above so sorry if mentioned.

I had similar problems. I switched my computer off via electric in-line socket on/off switch where all plugs pluged into. However, I left them plugged in and and assumed as power switch was off it wasn't a problem. Electricity was still getting through and giving me static shocks from the build up, so replace socket and/or actually unplug all devices after turned off. Good luck

Typical extension socket problem (e.g. Toshino & ASC brands) - the live and neutral are reversed so the switch switches off the neutral, not the live.

[h90]

Do be a slug like me and wait 12 years.

I'm going to assume you meant "don't"...

For me, 1 year and I'm still 'thinking' about it. And I live in a bungalow where digging an earth pit, driving in some rods and running a wire into the house would be a 1 hour job (not counting however long it would take me to find a store with earth rods and some cable)... Last time I 'thought' about it, not having a drill to make a hole in the outside wall to pass the new cable, was enough to get my ass back on the sofa... Maybe tomorrow...

You need to think this through a bit more.

You don't need to dig any pit, just hammer the rod in the ground.

The wire would be thin enough to pass trough between the window and the frame so no need for any hole drilling.

See the job already half done. A few more days thinking on the sofa and you can probably reduce the workload even more

SSSHHH!!!

I was thinking pit & 3 rods, and a 6mm cable... Old habits die hard, worked on contracts that demanded a max 1 ohm earth resistance...

Getting an earth to the fusebox is only half the battle. Whole house is wired with black&white cable, not twin&earth, that appears to be buried in the walls (no conduit), and all the sockets are 2 pin - so getting the earth to the sockets (and changing to 3 pin sockets) is a far bigger challenge than getting the earth...

Back to catching up with Spartacus...

You could but neutral on ground....it isn't nice but it is an upgrade from 1930s to 1960s safety standards.

[monte01]

Hi,

I have a similar problem, but I live in a rented house and it is not easy to instal an earth to the sockets in my office area. This may be a daft idea, but is it possible to earth all the electrics for the house one time, at say the trip box?

I am sure this is wishful thinking, but any comments would be good (always remembering of course to be grateful, because if I wasn't so stupid, you wouldn't look half so clever!)

Thanks

Monte

[Crossy]

I have a similar problem, but I live in a rented house and it is not easy to instal an earth to the sockets in my office area. This may be a daft idea, but is it possible to earth all the electrics for the house one time, at say the trip box?

Sadly no, you can't do that unless your outlets already have the third (green) wire and it's just not properly connected somewhere.

You could run a wire out of your office window to some suitable area and connect it directly to your PC case.

[cooked]

The trouble with these discussions is that most people don't understand diagrams and the like. I actually did one year of electrical engineering at university but don't understand what all this stuff about ohms and so on means, how do I install an ohm? How do I know, for instance, which is the neutral? I know which one it should be, tracing a lead through my house produces all sorts of different colours and improvisations. We need an idiot proof guide which doesn't need us to buy a multimeter, we have to do it ourselves as you will be well aware. When we moved here I wondered why there were bits of naked wire going through the wall and attached to a rusty nail vaguely stuck in the ground. Under an overhanging roof.

[bobl]

The trouble with these discussions is that most people don't understand diagrams and the like. I actually did one year of electrical engineering at university but don't understand what all this stuff about ohms and so on means, how do I install an ohm? How do I know, for instance, which is the neutral? I know which one it should be, tracing a lead through my house produces all sorts of different colours and improvisations. We need an idiot proof guide which doesn't need us to buy a multimeter, we have to do it ourselves as you will be well aware. When we moved here I wondered why there were bits of naked wire going through the wall and attached to a rusty nail vaguely stuck in the ground. Under an overhanging roof.

*Almost speechless*

A year studying electrical engineering and you don't know what an Ohm is? I had to read that 3 times to try to work out if you were being serious or not...

Sorry but in your case I would very strongly discourage "we have to do it ourselves"... For example "how do you know which is neutral?". You don't, if whoever wired your house simply used whatever scraps of wire they were able to scrounge up (sounds like, by your description). If you're serious about having work done, I'd highly recommend you seek the assistance of a professional.

[cooked]

Not for the first time, it is called satire, sigh.

Studying civil engineering ill prepared me for mixing concrete in a wheel barrow. Diagrams like the one above are completely incomprehensible to someone who doesn't know what 1 M ohm looks like, how do I get something with 1 M Ohm resistance?

I have tried all sorts of professionals around here they are useless, so if I follow your advice I may die anyway.

I have installed a circuit breaker and am hoping that that will be sufficient.

[manarak]

Not for the first time, it is called satire, sigh.

Studying civil engineering ill prepared me for mixing concrete in a wheel barrow. Diagrams like the one above are completely incomprehensible to someone who doesn't know what 1 M ohm looks like, how do I get something with 1 M Ohm resistance?

I have tried all sorts of professionals around here they are useless, so if I follow your advice I may die anyway.

I have installed a circuit breaker and am hoping that that will be sufficient.

Someone who doesn't understand the diagrams and who isn't a fast enough learner to learn it does not have the required mindset for doing electrical work that is potentially life threatening for himself and others and should not feel empowered nor encouraged by easy to understand directions.

[cooked]

Yes, as a body of professionals I always did find electricians to be an arrogant bunch. I was pointing put that the diagram only means something to another electrician. So why put it here, anyone that can understand it doesn't need it.

[Crossy]

Yes, as a body of professionals I always did find electricians to be an arrogant bunch. I was pointing put that the diagram only means something to another electrician. So why put it here, anyone that can understand it doesn't need it.

If you want arrogant try talking to UK gas installers! Talk about a secret society, more information comes out of the Freemasons.

Anyway, it's pretty well impossible to discuss wiring without some form of diagram. Most domestic electrical setups are simple and with a bit of basic knowledge and some cheap test gear (sorry you will need a multimeter and a neon screwdriver if you want to find faults on an existing system) it's not difficult to find out what's going on. The posted diagram is to show WHY the casework bites, it's not necessary to understand that in order to stop it.

Whatever, for our OP, to cure the tingle from the computer, connect the metalwork to ground in some way, shape or form.

[wpcoe]

Do be a slug like me and wait 12 years.

I'm going to assume you meant "don't"...

For me, 1 year and I'm still 'thinking' about it. And I live in a bungalow where digging an earth pit, driving in some rods and running a wire into the house would be a 1 hour job (not counting however long it would take me to find a store with earth rods and some cable)... Last time I 'thought' about it, not having a drill to make a hole in the outside wall to pass the new cable, was enough to get my ass back on the sofa... Maybe tomorrow...

Yeah, I had good intentions, but bad typing. DON'T wait, do it sooner rather than later. You actually sound a lot like me on the motivation/action front. Luckily, my townhouse actually had a ground rod with a thick cable leading to my consumer unit's ground bar and the consumer unit was on the wall directly above the outlet I needed to ground. But, it still took over a year of procrastination to run a half-meter length of ground wire and swap out the old 2-prong outlet for a 3-prong outlet.

[monte01]

Thank you all for your replies - I didn't mean to start a war! Crossy, you suggested that I might earth the computer directly ... unfortunately I have a laptop (still getting small shocks from the mouse buttons, and more scary ones from connections). Also I would like to earth other equipment such as the screen printer, speakers etc.

I am thinking of buying a new 3 pin multi plug socket - one of the ones in a box that sits on the wall, rather than dug into it. I would run a wire for live and neutral to a 2 pin plug, which would go into the existing 2 pin wall socket. I would then wire an earth from the new 3 pin socket to go out the window (or through the frame) to a proper earthing rod.

Would this work to earth the multiple devices? I know that I would have to be careful not to overload the one original socket.

The solution is a little convoluted, but as I said in my earlier mail, I am in a rented house, and cannot go rewiring or digging out wires from the walls.

Thanks

David

[innerspace]

Doing this should work fine.

Consider adding a ups (uninterupible power supply) box into the one good earthed socket and running the rest off that.

Will provide a touch of surge protection, even the electric supply a bit and provide a few minutes of power in a blackout.

They may cost a few thousand baht and die every year or 2 but help protect more expensive kit. Though having them earthed will lengthen their life and they pass on that benefit to other devices.

Printers will normally not overload them in an outage but most good ups have a surge protection only port for printers that doesnt offer backup supply.

[monte01]

thanks Innerspace

[Crossy]

Many 3-pin multi adapters come with one of these

Which is a convenient way of connecting to the earth pin. A wire from the tab to a simple ground stake will do the job and provide grounding to anything plugged in to the strip.

With a laptop there's no real need for a UPS, but if you have a separate router it will keep that going during power outages. An inkjet printer won't give most UPSs any problems, the printer outlet (not backed up) is intended for laser printers which will give the UPS a headache.

With the type of IT gear most people have you're going to find it difficult to overload a single outlet.

[monte01]

thanks Crossy

[bobl]

Not for the first time, it is called satire, sigh.

If having to explain that your posts are intended to be satirical is a recurring theme for you, then perhaps satire doesn't mean what you think it means.

"Hey guys - I have the same problem and I've learned a lot from this thread. Clearly I need to install an Ohm. Can I get one at Homepro? Do they come with instructions? Would you recommend I buy two so that I can keep one as a spare?" would be satire. Suggesting you've studied electrical engineering at university level - but that you don't know who Ohm is, isn't...

[cooked]

Not for the first time, it is called satire, sigh.

If having to explain that your posts are intended to be satirical is a recurring theme for you, then perhaps satire doesn't mean what you think it means.

"Hey guys - I have the same problem and I've learned a lot from this thread. Clearly I need to install an Ohm. Can I get one at Homepro? Do they come with instructions? Would you recommend I buy two so that I can keep one as a spare?" would be satire. Suggesting you've studied electrical engineering at university level - but that you don't know who Ohm is, isn't...

Look at the diagram. Do you think it means anything at all to a layman? Sorry I went too fast for you. What will he do when confronted with this kind of thing, go to a shop and buy 1000 Ohms? Completely useless for the OP.

I don't think I'll be changing my style to make it comprehensible to the humourless and very often arrogant band of guys that call themselves electricians.I had the misfortune with working with a group of these guys, no way would they ever explain anything or admit that there was something they didn't know.

[Crossy]

I don't think I'll be changing my style to make it comprehensible to the humourless and very often arrogant band of guys that call themselves electricians.I had the misfortune with working with a group of these guys, no way would they ever explain anything or admit that there was something they didn't know.

Please don't tar all with the same brush, and don't forget :-

7) Not to post slurs or degrading comments directed towards any group on the basis of race, nationality, religion, gender or sexual orientation.

Despite not being mentioned explicitly I think it applies to Electricians too, do we really need to add 'profession' to the list?

Let's keep it civil chaps

[monte01]

Hi Crossy, Innerspace,

I followed your advice and now have an earthed socket for my computer. Thank you. No more shocks.

Innerspace, I followed your advice and connected through a UPS. It is one that I have been using for a while, made by Ablerex. A word of warning though ...

When I pulled out the plug from my laptop yesterday, the whole socket came out of the back of the UPS. To my surprise, it was not earthed, even though it was a three pin socket ... so all my earthing was to no avail. From your comments Crossy, a UPS is not so critical for a laptop because it has a separate charger/voltage regulator, so for now I am running without.

Can you tell me if it is standard for UPS units not to carry an earth wire to the nperipherals plugged into it? If not, is there any way to tell when you buy a UPS, or failing that particular brands/models to look out for.

Thanks

David

[JetsetBkk]

Hi Crossy, Innerspace,

I followed your advice and now have an earthed socket for my computer. Thank you. No more shocks.

Innerspace, I followed your advice and connected through a UPS. It is one that I have been using for a while, made by Ablerex. A word of warning though ...

When I pulled out the plug from my laptop yesterday, the whole socket came out of the back of the UPS. To my surprise, it was not earthed, even though it was a three pin socket ... so all my earthing was to no avail. From your comments Crossy, a UPS is not so critical for a laptop because it has a separate charger/voltage regulator, so for now I am running without.

Can you tell me if it is standard for UPS units not to carry an earth wire to the nperipherals plugged into it? If not, is there any way to tell when you buy a UPS, or failing that particular brands/models to look out for.

Thanks

David

APC is considered by most to be a good brand. I have two: a model "Back-UPS RS 500" and model "Back-UPS Pro 900".

Neither of these models has the usual Thai socket as an output, so you have to beware of that and make sure you can get the correct cable. The first model I have came with two such cables (for its 3 outlets) and the second model came with none.

APC do make another model with 3 outlets on the top side into which you can plug standard Thai plugs.

Edited February 23, 2013 by JetsetBkk

[manarak]

UPDATE: I have now grounded the plug and my computers don't bite me anymore

[wpcoe]

Good job. Now let's see how long it takes you to not be surprised when you touch them and they don't bite!

Months later, it still feels odd when I can touch the computer case or end of a plugged in USB cable and not get a tingle.

[MickGC]

Don't go about barefooted....... you make the ground, so put rubber between you and floor, so what you touch is not grounding it. even flip flops. or those 49 baht rubber slip ones

Thanks guys, some great advice here. I was also getting constant electrical tingles around the house especially from my computer equipment. I now wear a pair of thongs/flip-flops as "ignis" suggested and and was shocked to find I was getting no more more shocks. A temporary solution I know, but it works.

[bluegum]

I have some questions about my grounding wire system at home. I would appreciate any comments from knowledgeable folk. First, however, I'll outline what I've done so far.

I too was getting tingles off various appliances. So I undertook (after reading up on TV and other relevant sites) to add grounding wires to some of the plug points (all 2 pin) in my antiquated Bangkok home. Also, to protect my shiny new hifi and PC I bought some power strips labelled as 'surge protectors'. They have a green light labelled 'grounded' that of course did not light up with the old 2-wire system.

My grounding rod is now in place and following a lot of scrambling under the house and multi-meter-testing of colored wires that stuck out of the holes in the wall, i finally have 3 pin receptacles in place and correctly wired up. I realised that several of the old wall plug points had been wired in reverse and it was only when I corrected this that the green light on the surge protector came on.

Considering the job done, I began to tidy up around the grounding rod (some of my earth wires were longer than necessary and needed to be recut and attached for a tidy finish). Out of interest I touched the multimeter probes on the loose earth wire and the bare grounding rod. I was v. surprised to get an an approx. 50 V reading on the earth wires running towards the grounding rod. Further investigation showed that with no load on the plug point, its corresponding earth wire showed no such unexpected voltage. However, running a lamp or a fan or just plugging in my surge protector strip (empty) brought about the 50 V on the earth wire. This behaviour occurs on all 4 of the earth wires connected to the plug receptacles I wired up. BTW, they are on 20 amp breakers, which I access across the other side of the house.

My limited knowledge tells me that this is not a good situation - it compromises the basic function of the earthing process, and reflects that there is a significant problem somewhere.

My 2 questions are:

How dangerous is this situation? What could be causing this loose voltage?

[h90]

Don't go about barefooted....... you make the ground, so put rubber between you and floor, so what you touch is not grounding it. even flip flops. or those 49 baht rubber slip ones

Thanks guys, some great advice here. I was also getting constant electrical tingles around the house especially from my computer equipment. I now wear a pair of thongs/flip-flops as "ignis" suggested and and was shocked to find I was getting no more more shocks. A temporary solution I know, but it works.

old trick, take heavy shoes and you can work the 220 Volt wires and touch it. Which only works if no electric is used.

take the life wire and twist it with the other wire to the turned off light--> no problem

take the life wire and take the other wire to the turned on light and the electric will pass your body--> you'll perform a nice break dance...

(twisting wires together is a very bad idea.)

flip flops might be enough to be insulated from the ground.

Anyway not healthy to play around with 220 Volt, people with weak heart or bad luck can die from it.

[h90]

I have some questions about my grounding wire system at home. I would appreciate any comments from knowledgeable folk. First, however, I'll outline what I've done so far.

I too was getting tingles off various appliances. So I undertook (after reading up on TV and other relevant sites) to add grounding wires to some of the plug points (all 2 pin) in my antiquated Bangkok home. Also, to protect my shiny new hifi and PC I bought some power strips labelled as 'surge protectors'. They have a green light labelled 'grounded' that of course did not light up with the old 2-wire system.

My grounding rod is now in place and following a lot of scrambling under the house and multi-meter-testing of colored wires that stuck out of the holes in the wall, i finally have 3 pin receptacles in place and correctly wired up. I realised that several of the old wall plug points had been wired in reverse and it was only when I corrected this that the green light on the surge protector came on.

Considering the job done, I began to tidy up around the grounding rod (some of my earth wires were longer than necessary and needed to be recut and attached for a tidy finish). Out of interest I touched the multimeter probes on the loose earth wire and the bare grounding rod. I was v. surprised to get an an approx. 50 V reading on the earth wires running towards the grounding rod. Further investigation showed that with no load on the plug point, its corresponding earth wire showed no such unexpected voltage. However, running a lamp or a fan or just plugging in my surge protector strip (empty) brought about the 50 V on the earth wire. This behaviour occurs on all 4 of the earth wires connected to the plug receptacles I wired up. BTW, they are on 20 amp breakers, which I access across the other side of the house.

My limited knowledge tells me that this is not a good situation - it compromises the basic function of the earthing process, and reflects that there is a significant problem somewhere.

My 2 questions are:

How dangerous is this situation? What could be causing this loose voltage?

It is normal....disconnect the ground wire from the rod and I have a good 50 Volt as well.

But there should be only very low Ampere flowing when connected.

Also do check, if you didn't do the wiring yourself:

Ground wire is not connected with the Zero wire.

on the plugs Ground wire and Zero is not mixed. I had that on one plug and it shot me the interface of a CNC lathe twice.

[bluegum]

thanks for your feedback h90.

Actually i have been finding voltages greater than 50 volts on occasion, but at low amperage, as you mentioned. No, my wires are not crossed (only metaphorically, perhaps). I still wonder how could the presence of such a voltage in the earth wire not affect the safety function of said wire. After all, isn't it called earth because of its v. low (near zero) potential?

Edited July 26, 2013 by bluegum

[h90]

thanks for your feedback h90.

Actually i have been finding voltages greater than 50 volts on occasion, but at low amperage, as you mentioned. No, my wires are not crossed (only metaphorically, perhaps). I still wonder how could the presence of such a voltage in the earth wire not affect the safety function of said wire. After all, isn't it called earth because of its v. low (near zero) potential?

Well once the wire is connected with the earth-rod (earthing rod????) the voltage should be zero. Only if not connected to the rod it should show voltage.

I run the following test:

I connected a 50 Watt bulb with power and earth. It should almost light as bright as if connected with ground (zero).

If not the rod is not OK, not deep enough, not connected good, etc..

I measure from the plug to the rod and the resistance should be zero. It wasn't in my case because they just twisted the wires together. I soldered them together --> problem fixed.

I measured ground (zero) to earth, there should be some voltage and resistance. If not they cheated....