0
\$\begingroup\$

So I live in an EU country and don't have Earth grounding for my house. Still I am getting shocked when touching "hot" line (220VAC) and standing on "ground" (Earth). How is this possible?

From my understanding it needs to close a circuit to generate a current flow through my body. I heard of some sort of capacitance that can close the circuit, but didn't fully understand the concept. (It will close the circuit between "ground" and neutral through air ?? So current will flow through me, ground and neutral)

So to extend this idea, if getting a "hot" line somewhere far from civilization will cause a current to flow through me and then "ground", going back to the source.

Neutral line is not touched in any way. Just floating.

\$\endgroup\$
  • 1
    \$\begingroup\$ You are getting shocked. Electrocution is a combination of "electric" and "execution." \$\endgroup\$ – mkeith Jul 30 '18 at 17:39
  • 1
    \$\begingroup\$ you must be grounded; they work on 250kv lines from helicopters w/o issue. \$\endgroup\$ – dandavis Jul 30 '18 at 17:44
  • 13
    \$\begingroup\$ You should stop playing with electricity now... \$\endgroup\$ – Solar Mike Jul 30 '18 at 17:45
  • 1
    \$\begingroup\$ Neutral is never floating. It is grounded both at your house AND at the HV transformer. \$\endgroup\$ – Turbo J Jul 30 '18 at 18:10
  • 6
    \$\begingroup\$ Note that even neutral can kill you - it just needs specific fault conditions, which old cabling can provide. Please do not work on 230V when you are not educated to do so. \$\endgroup\$ – Turbo J Jul 30 '18 at 18:12
5
\$\begingroup\$

You are completing a circuit.

In most homes there is a connection between Earth/Ground and Neutral at or near the point where the electrical supply enters the building.

So the circuit is from the hot side of the supply to the "hot" line you are touching, through you, into the ground, along the ground, into the earthing conductors for the building, through the ground-neutral link into the neutral side of the supply.

enter image description here

See also 2nd diagram at shock current path

\$\endgroup\$
  • 1
    \$\begingroup\$ This appears to be a picture of a US installation, but except for the wire colors, it's a lot like what EU countries do. We call the grounded neutral between the transformer and the point where it enters the house PEN (because it's Protective Earth and Neutral at the same time). After it leaves the main fuse box, PE (Protective Earth, green/yellow) and N (Neutral, blue) use separate wires, just like in the picture above. We do have old installations where the single PEN wire is brought to every socket, and only there is a little bridge from the N contact to the PE contact. Note the PE in PEN! \$\endgroup\$ – zebonaut Jul 31 '18 at 9:22
2
\$\begingroup\$

You probably do have earth grounding. The "neutral" wire is probably grounded somewhere where you can't see it. When you touch the hot wire, current flows through your body and maybe your shoes to the floor, and eventually back to the source, through ground and maybe through some part of the neutral wire.

\$\endgroup\$
  • \$\begingroup\$ So without a "ground" it would be impossible to close the circuit and I can "blame" the neighbours grounding ? (I know that every house should have grounding, and maybe I do, but didn't closely search ) \$\endgroup\$ – Ursescu Ionut Jul 30 '18 at 18:47
  • 2
    \$\begingroup\$ Here is how I would say it: if you touch one conductor from a TRULY isolated voltage source, you cannot get a shock. It is difficult to maintain a truly isolated voltage source. This is why people have universally adopted the concept of using grounding. In a system that is grounded, and that uses GFI (or RCD) breakers, shock safety is pretty good. Basically a solved problem. \$\endgroup\$ – mkeith Jul 30 '18 at 18:52
2
\$\begingroup\$

It is normal for the neutral to be grounded at the transformer. It may be grounded in other places as well, such as in other people's homes.

So the circuit is from the transformer, along the hot wire, through you to the ground, through the ground to the earth rod at the transformer, through the connection between earth and neutral at the transformer.

May I suggest a couple of things?

  1. Stop touching the hot wire. One day you will be better grounded than usual. It only takes about 30mA to kill a person.
  2. Get your home electrics fixed.
\$\endgroup\$
0
\$\begingroup\$

Grounding is a safety measure - it's done to prevent too high voltages inside electric equipment in cases of serious high voltage line faults or lightning. Think for example a water pump. The local ground potential jumps due a lightning strike or a HV line drops down. The water pump goes under enormous stress if the electric supply system doesn't get the same potential jump. Grounding brings the potential jump to the electricity supply wires and nothing special happens - except maybe a violent arcing in the protection tubes of the local electicity delivery transformer station.

The wires which bring the electricity to your house are connected to the same transformer than the lines which supply the neighbour. If you have omitted the local grounding of the neutral line, the neighbour can be more careful. As a side product you have a voltage between your local ground and the live voltage line. As a bonus you get a reduced voltage between your local ground and the neutral line in case of HV faults and lightning.

\$\endgroup\$
0
\$\begingroup\$

There exists some 100pf of capacitance around your body, effectively turning you into antenna. The human body also has roughly 2kΩ of resistance at 220V, so whatever your standing on or touching can become a pathway (which means the pathway is roughly 500kΩ, people generally start feeling current at 0.25uA.

Everything has resistance, even air (although its usually 10^7 Ohms or greater), the floor (wood is ~100k), walls and the foundation of your house all have resistance. While it is probably quite high, its not as high as you would think.

Interesting table, resistance of the human body:

enter image description here
Source: Wikipedia Electric Injury

\$\endgroup\$
0
\$\begingroup\$

"I live in an EU country and don't have Earth grounding for my house." That is a common situation in some countries, but is NOT the case in the USA.

For the "EU" style system, imagine a power company transformer somewhere near your house. That transformer steps down a very high AC voltage (1000-5000VAC) to the 220VAC that you expect and routes that lower voltage to one or more customers via a pair of wires. There is no formal (i.e. deliberate) grounding provided; both of the 220VAC wires are ideally floating, not connected anywhere to ground. However, there are at least two causes why touching a 220VAC wire at the same time as earth/ground can produce a shock (or worse).

First case: The transformer itself has capacitance between its high voltage AC input and its low voltage (220VAC) output; this means that AC current can flow through that capacitance from the high voltage primary wires into one or both of the low voltage secondary wires. [All capacitors can pass AC current of some amount, with little being required to shock a person.] The current flows through the capacitance, through the low voltage wire, and through you to earth. Meanwhile...somewhere (perhaps many kms away) there is a connection from the high voltage wires to earth via either another capacitive path or via a direct connection. After shocking you, the current passes through the earth all the way back to the distant ground (either direct or through capacitance) of the high voltage wire...completing the necessary loop for current flow.

Second case: 220VAC is available to your neighbor using the same wires that provide 220VAC for you. However, your neighbor has either deliberately or accidentally made a connection (either direct or via capacitance) between one of his 220VAC wires and earth. That means that the wire your neighbor has NOT made a connection to is now 220VAC relative to earth--it is no longer floating. If you touch the wire your neighbor has not grounded, you will certainly be shocked (or killed).

In reality, both cases (and others) can exist at the same time, complicating the analysis but still shocking you. :)

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.