Lack of Earth wire

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.


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.


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.

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Wiring