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Electricity connections where I live don't have have earth wires, only live and neutral.

I don't have any problems with it but if I touch metal parts of any desktop computer, It does what coffee can never do, even stuff attached to usb can deliver a good enough shock like a smartphone with exposed metal and its not just the case for one particular computer, all computers those have a psu in it will do the same but only if any of my body parts are touching the ground (as in earth) or if my shoes are wet

Question[s]: what can I do to prevent this from happening, specially when I am planning to use one of my old psu's as lab bench power supply, Also can it damage my devices like a smartphone connected to a usb port, it never hurt anything but devices like an mcu are very fragile, touching any pins while mcu is hooked to a usb port does shock sometimes.

Lets say I connect the body of a psu (or earth wire) to a water pipe thats nicely grounded, will it constantly leak electricity causing increased bills? How much voltage/amps/watts usually are they?

I have 220v ac connection, 110v isn't available neither a connection with an earth wire

Edit: Shock is not enough to hurt, if I touch firmly I won't even feel anything, its more related to logic than safety like why only computer power supplies do that or if it can damage any device?

asim
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    Not all electrical codes are made equal! Saying where you are can help - electrical networks are quite diverse all over the world. A sound advice for one place can as well be very bad (deadly) elsewhere. – fraxinus Mar 30 '20 at 15:58

7 Answers7

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The problem is well known and people even create it with audio equipment - they take plastic tape and break the protective ground wires of their mains AC supply cables to avoid ground loops which make low cost unbalanced audio signals to catch noise.

Those audio users often do not get electricity on their hands because they keep one device in the system grounded and the rest are grounded via the signal cables. The problems start as soon as some of the wires is missing, for ex an unaware participant takes it off. The game can turn lethal if there's somewhere a fault which brings the mains AC directly to touchable parts; proper grounding would trip the breaker in that case.

Many computers and other equipment are unfortunately designed to work properly only with protective ground wire connected. Without it the devices feed to all touchable metal parts 50% of mains AC voltage through their radio emission protection filters in their power supplies. Those filters typically have capacitors from both line and neutral wires to the metal case and that's a capacitive 50% voltage divider.

Fortunately the capacitors are generally small enough and the current isn't lethal, only harmful. But it can kill electronics: It can fry permanently something when you connect a cable from one device to another. I have seen several computers, peripherals and audio devices destroyed this way. People have said "I saw sparks and when I finally got the wire connected the device was quiet"

A good idea is to make a local ground wire. Connect it to a reliable ground point. Consult a competent electrician who understands the local system. Do not try own solutions if you do not master the subject.

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This is about to kill you

Electricity is fickle. Or to be more precise, conductivity of skin, shoes, floors and whatever is ground-faulting there is highly variable. Right now, the current is limiting itself to in the 1-5 milliamp range. However a change in conductivity (rain raises the water table etc.) could make that jump up into the 20-100 milliamp range and then it kills you.

Keep in mind, this exact thing has happened to millions of people. Some of them were unlucky the first time. They don't talk about it; they appear in obituaries.

Your attitude is "So far it's only tingled me, so that's the worst it will do". That attitude is wrong.

It's hard because I'll be blunt - 99% of the time you do get lucky. I've been zapped dozens of times myself. But I've also been educated that the 1% is a real thing and people die just doing the things I was doing. And how to mitigate those risks. If you had a gun with 100 chambers, would you play Russian Roulette? I'm not going to quit doing electrical, but I'll use every trick known to man to take that chance as rarely as possible.

It's a ground fault.

Normally, current flows from hot, through the intended current paths in the device, and then back to neutral. (or the other hot if you're in split-phase parts of the Philippines).

Normally, that current path is supposed to be entirely insulated from the chassis or box. The current should not interact with the equipment case at all - at least mains current shouldn't; low-voltage DC current is operating in a different loop and should be fully isolated from mains.

Sometimes things have weak or deteriorated insulation. When that happens, mains current can "leak" to places it should not be. This is called a "ground fault" in North American parlance or "residual current" in European parlance.

A ground fault is simply a defect in the equipment. The equipment is broken; it should be repaired or replaced.

We deal with these all the time over on diy.se, and people usually get testy: "Surely my equipment doesn't have a ground fault!" They will go crazy; they'll spend $40 - twice! - replacing GFCI breakers, from total disbelief Don't waste your time on that.

Grounding protects you. It doesn't remove the ground fault.

With metal-chassis equipment, if that is properly grounded with a neutral-ground equipotential bond, then the fault path through you will be tens of ohms (fractions of siemens; conductance in siemens is 1 / resistance in ohms), and the fault path through the wired ground and the N-G equipotential bond will be milliohms (many siemens). Current flows on all paths in proportion with conductance, so virtually all the current will return on the wired ground.

If the faulty device itself is causing current flow to be limited (say: there's a 10k resistor between mains and chassis), then that small current will flow back, through the grounding system, through the neutral-ground equipotential bond, and back to neutral (source). If the device is not limiting current flow, then this current will flow in tens or hundreds of amps and will snap the circuit breaker. This is working as intended.

One way to stop this from happening is to remove the ground. Now the power supply chassis will sit there charged at mains potential, and people go "well I'm not fixing it since it's just a tingle, and a tingle never killed anybody". (Darwin award incoming).

Your other option is GFCI/RCD, but that will only shut it off.

Another option for ground-fault protection is a Ground Fault Circuit Interruptor or Residual Current Device. These come in a huge variety of forms - everything from circuit breakers to socket adapters.

However, this will not do what you want. This will not let you keep using the faulty device. This will shut power off if a hazardous amount of current flows, saving your life.

Most people call this a "Nuisance Trip", and the only thing they see is that power was turned off for no good reason, and this only started happening after they put on the GFCI device. Therefore the nuisance trips are the GFCI's fault.

"Islanding" grounds

It gets more insidious. Imagine you have six PCs plugged into a power strip. It's a bog-standard power strip with grounded plugs. On this strip, the grounds are connected to each other.

Now it's plugged into a 2-plug wall socket. Internal to that wall socket, you guessed it, the plug's grounds are connected to each other. But behind the wall socket it's connected to nothing.

I call this situation an "Island of grounds". The grounds connect to each other, but not back to the panel and its vital neutral-ground equipotential bond. What happens to a ground fault? It can't go back to the panel to be grounded out. So it simply goes where it can go -- every other device.

This means a single faulty device will "light up" the grounds on every device. The devices are sharing the ground fault. The faulty device could be any one of them. And you have to separate and diagnose that.

Grounding only works if there's a competent ground all the way back to the panel, N-G bond and earthing rods.

What you really need to do.

The bottom line is that the faulty device needs to be serviced or replaced. But that's not 1/10 of your problem. The big problem is that any future device fault could easily kill you.

For that reason, you should either fit GFCI/RCD devices to protect you... or retrofit grounds.

However, a ground retrofit is "fake safety" unless you actually install it properly. This must include a neutral-ground equipotential bond at the appropriate location. You cannot simply carry fault current to an earth rod or pipe and call it a day. All that will do is electrify all your grounds, and the earth around your house also! That's super fun when you have a dog chained up with a metal chain. It also drives livestock crazy.

That is because dirt is a very poor conductor (that's why we don't just wrap dirt in insulation and call it wire). The dirt is so poor that it will impede the flow of current too much. A bolted ground fault that should trip the breaker, won't, and will just electrify the ground.

While water service pipe may be an effective ground rod, using interior water pipe as a substitute for a proper ground wire is a very bad idea. Plastic piping is a thing, and the water company may not tell you when they change your metal meter for a plastic smart meter.

Harper - Reinstate Monica
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    Wow, I have accidentally touched live wires many times but never got scared as much as your answer does. I have around a dozen power supplies, 2 currently attached (+ came with branded +) computers, All of them cannot be faulty, I will try to be extra careful anyway specially when doctors are busy :(, thanks – asim Mar 29 '20 at 21:35
  • I did all the wiring myself, there is no ground, i have both 2 and 3 pinned sockets but 3pinned ones have nothing attached to ground, they are just a necessity because otherwise alots of convertors would be required – asim Mar 29 '20 at 21:53
  • And also as i mentioned in my question, i am planning to use one psu as lab bench powersupply so i tested like 4 power supplies, all of them more or less do tingle @Harper – asim Mar 29 '20 at 21:55
  • I deleted and reposted this comment. @asim Well if they're all plugged into grounded power strips, or a grounded receptacle, and that ground does not go all the way back to the panel, they will "share ground faults". Most likely you have one faulting device that's electrifying every ground. I just added a section on that. But you've got to find a way to test this without using yourself as a shockmeter. You'll meet your maker doing that. – Harper - Reinstate Monica Mar 29 '20 at 21:57
  • +1 for the suggestion of not using myself as a shockmeter, i do have that bad habit even when i have testers and a few multimeters handy – asim Mar 29 '20 at 22:06
  • If you did all this yourself, all due respect but there also may be a plain wiring fault. You are new to this, and don't believe in the picayune belt-and-suspenders ideology of the Electrical Code. Honestly, 99% of the time you get lucky. Electricians are careful because they've seen the data on the 1%. It's Russian Roulette with a revolver with 100 chambers. That doesn't make it OK to play. – Harper - Reinstate Monica Mar 29 '20 at 22:31
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There are many places where the public supply doesn't have an earth, and you are expected to supply your own. That is usually in the form of a metal rod banged into the ground as deep as possible. But in particularly dry areas, a single rod many not be enough. It may require several rods, spaced well apart, or something more substantial like a buried earth grid. The earth rod is connected to the ground pins of each socket.

In such systems, an RCD or GFCI (same thing, different names) can make the installation much safer. The amount of current required to electrocute you is so low that it will not trip any circuit breaker or blow a fuse. Only the RCD will protect you from electrocution.

Simon B
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  • Isn't the earth provided per-installation *everywhere*? – chrylis -cautiouslyoptimistic- Mar 30 '20 at 07:09
  • @chrylis-onstrike- If it's a "TT" supply, then the supplier only gives phase and neutral. The neutral is earthed at the transformer, but the customer provides the earth at their end. Here in the UK, it is still common in rural areas. – Simon B Mar 30 '20 at 07:23
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Your building/home should have a ground/earth stake. Sometimes called an earth rod, its a metal spike going into the ground.

If this has been removed or disconnected then your home is no longer code compliant and needs fixing urgently.

Look around for something like this:

From wikipedia

It should NOT look like this:

enter image description here

Other causes for failure could inclode

  • Excessively dry ground - pour a couple buckets of plain water on the area to moisten the soil.
  • Oxidisation - clean off all contamination to achieve a good conductive connection.
Criggie
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    The question states the following: _Electricity connections where I live don't have have earth wires, only live and neutral._ – Num Lock Mar 30 '20 at 06:29
  • Where I live (NW Europe), older properties did not have to have earth wires on sockets and it is not necessary to update these except in the kitchen or bathroom or for certain electrical appliances. – rghome Mar 30 '20 at 06:57
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    @NumLock unless the sockets don’t have an Earth port, there’s nothing stopping one adding a ground to your house. – Tim Mar 30 '20 at 20:34
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    @Tim, in large parts of the world, the common sockets don't have an Earth port. – Mark Mar 31 '20 at 02:19
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If your smartphone is isolated (not connected to the earth in any way), it will not be damaged. However, that may not be the case since there will be metallic parts sticking out such as the front speakers which may touch your body which in turn is connected to the ground.

In order to prevent the electric shocks, you may choose to make a local earth connection; i.e. literally dig up a hole, stick in a wire and use the extended wire for earthing devices.

Aaron John Sabu
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I have all three wires in my home, while charging the phone I have the same behaviour. The phone charger does not even have a ground connection pin, only two are present. I have changed many phone brands: Huawei , Samsung, Nokia, ... no one has the ground. So this issue will persist.

The laptop is different story, it might have a ground connection and it is probably connected to the frame of the computer. The PC computer has its case entirely grounded.

Also can it damage my devices like a smartphone connected to a usb port, it never hurt anything but devices like an mcu are very fragile, touching any pins while mcu is hooked to a usb port does shock sometimes.

This can happen even with ground connected, from my experience I already burned a MCU/PLC and laptop serial port by connecting the cable. It's an electrostatic discharge. The only way to prevent this is to use anti-static wrist strap or mat that is connected to ground.

Lets say I connect the body of a psu (or earth wire) to a water pipe thats nicely grounded, will it constantly leak electricity causing increased bills? How much voltage/amps/watts usually are they?

It will leak only if the device is damaged, electric shock hazard. That's why the 3rd (ground) wire serves - to save life. No bills or whatsoever would you encounter.

My advice: Pull the ground wire. Use wrist strap.

Marko Buršič
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    I am not sure if its electrostatic because my understanding of it is when your body gets charged without touching any electric parts like from combing your hair – asim Mar 28 '20 at 22:35
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Earth and neutral should be connected by the utility. In any case get an electrician to test your earth connection. He can also report to the utility if your neutral is not earthed properly.

It should be safe to touch any exposed surface in your installation. If you are shocked, it is dangerous.

skvery
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    We don't do that here, thats why i asked – asim Mar 28 '20 at 21:31
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    OP explained that there is no earth in the system. The shock being experienced may be due to Y-capacitors in the power supplies and this is a problem on many 2-pin PSUs whether or not an earth connection is available and whether or not the neutral is truly neutralised. Even on a proper supply the Y-caps will tend to pull the "isolated" output to half the AC supply voltage. – Transistor Mar 28 '20 at 21:34
  • The utility should still connect neutral to earth at the supply side. Touching surfaces should be safe and without shock. – skvery Mar 28 '20 at 21:42
  • I'm explaining that that is not the case. See the post with the circuit schematic [here](https://www.eevblog.com/forum/chat/does-this-sound-acceptable-for-an-apple-product/). You can see that the DC GND is capacitively coupled to mid AC supply. You will feel a tingle when you touch the DC GND. – Transistor Mar 28 '20 at 21:56
  • @Transistor Not a tingle here bud, OP said shock. – skvery Mar 28 '20 at 22:00
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    Read the OP's last paragraph edit. It sounds like Y-cap to me. I get the same thing on an Ikea lamp with SMPS power supply on a 230 V, L+N+E system in my house. The PSU earth pin is not connected (as IKEA would sell this in 2-pin variety for most of Europe but Ireland uses UK-style 13A plug so they just leave the earth pin disconnected). – Transistor Mar 28 '20 at 22:05
  • Equipment that have 3-prong plugs must be connected to earthed socket, or the equipment case may give a shock and can damage other equipment if connected while plugged in. – Justme Mar 28 '20 at 22:08
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    In any case, @asim should arrange an earth line (either by doing it himself or asking a professional if he can't), for his own safety, Make sure the wall sockets have an earth connection, meaning that there are 3 wire coming to the socket, if not pull a yellow-green wire from the closest earth terminal to the socket. If the socket has no earth connection, change the socket. – Fredled Mar 28 '20 at 22:10
  • What justme said makes sense as all psu's have 3 wires, @fredled i do have a pipe for water supply buried 150+ feet deep underground, guess i will use it then – asim Mar 28 '20 at 22:15
  • @asim Make surre your pipe is metallic all the way to earth and not isolated from earth (plastic or other material). Also check with a multimeter the quality of the connection. – Fredled Mar 28 '20 at 22:23
  • @Fredled its all metal, 6" diameter pipe all the way to the bottom with plastic pipes and wiring for a submersible pump all housed inside that pipe – asim Mar 28 '20 at 22:25
  • @asim If the metal pipe you are talking about is going deep into the earth, try to attach a yellow-green copper wire to it but it may be difficult to obtain a good connection without fixing it solidly, so you must find a bolt where can screw it. Or you will have to weld a screw on it but it can be risky for what is inside. If you just wrapp it around it won't be good. In this case you can digg the cable (islation removed) in the earth, attached to a rod dug 6 or 10 feet deep. And iron rod is OK and cheaper than a copper rod. – Fredled Mar 28 '20 at 22:44
  • Digging earth won't help here if the mains socket still has only 2 prongs. Usually Neutral is already bonded to earth/ground at some bonding point, and from that same bonding point the yellow-green PE wire is distributed to mains sockets along with Neutral and Live. Sometimes really old systems just connected Neutral to the Ground at each mains socket locally. The OP needs an eletrician to add properly grounded mains socket. – Justme Mar 28 '20 at 23:12
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    I did the whole wiring myself @justme, no one here have earth wires they don't exist – asim Mar 29 '20 at 08:19
  • @asim if earth wires "don't exist" there, then you should not be using any appliance with an earth pin on its mains plug. At all. Whatsoever. You should be using only "double insulated" appliances and low-voltage appliances lacking an earth pin. If you're going to use things that have an earth pin, then EARTH THEM. Or, you know, risk your life. It's your call. – Sod Almighty Mar 30 '20 at 22:03
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    Also, if you have to ask these kinds of questions in the first place, you shouldn't be wiring your own house! – Sod Almighty Mar 30 '20 at 22:05