2
\$\begingroup\$

I have a series of questions in regards to grounding and ESD, posting those in one topic as they're all related. This is located in Poland. I'm not too concerned about legality of grounding to neutral, as this definitely shouldn't be done in my opinion and it will be removed asap. I'm concerned about electronic principles as a whole.

  1. We converted the basement in our building to a server room, the initial power supply to the basement was from the shared basement light power supply. There was no ground connection, I only realized that when I felt a tingling feeling when I touched the Earth bolt in the mains socket. Luckily, I installed an RCD there. During these few days, an ethernet cable was connected from the basement up to the apartment. The apartment doesn't have ground either, turns out the ground is shorted to the neutral wire. Could that have caused issues, damage the switch for example? Does grounding have anything to do with devices that are powered by 12 volts? I'm aware that there exist isolated power supplies, but then some are grounded to neutral/ground? One of them has no ground bolt at the mains plug even, the rack switch does.
  2. I have since then grounded the basement to a water pipe, there is no more tingling feeling. However, the apartment upstairs is still on the neutral ground. I fear this difference can potentially cause issues with the switches since the ethernet cable doesn't have a common ground. Am I right?
  3. Yesterday we ran a direct wire from the apartment to the basement so that the basement is under the home electricity meter. Basement is still earthed to the pipe, apartment still on neutral, no common ground between those. This will be fixed as I am pushing to remove the neutral-ground wire connection and to connect the ground wire coming from the basement (which is currently disconnected) so that there is only one grounding point for the apartment and the basement. Is this a good idea? I feel the current setup is dangerous not only due to the possibility of neutral becoming live, but also from the fact my equipment might be damaged.
  4. During this semi-live connection, my dad seem to have touched something and it shut off the fuse in the apartment which had to be reset. Since then, my phone charger stopped working. I am really confused as to why this would happen. Even if he did short something for a moment, why would the charger die. I kept thinking about it and it made me realize that here in the apartment, I keep getting electrostatically charged by the couch, I used to touch the ground in the mains socket to discharge (since I had sparked my laptop many times by accident). Since ground is connected to neutral, could that spike of voltage damage the charger or pretty much anything connected in the house? This makes no sense to me, since we're talking about AC power and ESD, but I'm trying to understand if my repetitive ESD discharges to the neutral wire could have caused damage to connected equipment or weaken it and it just was a coincidence that the charger failed at the time we disconnected the power during the wire installation.
  5. I keep regularly (yet accidentally) discharging ESD into my laptop chassis, phone and other things. Sometimes when connected to their chargers and sometimes when not. What would be the most likely affected device? I'm believing that when the charger is connected, the charger would take it all since it's 'grounded' in a way?

Thanks, hopefully I explained it right and the answers will help with my understanding of those concepts

\$\endgroup\$
3
  • \$\begingroup\$ This is going to involve legal codes, wiring regulations, which are not the same across the world. Therefore it's worth editing the question to say where you are. \$\endgroup\$
    – user16324
    Commented Oct 15, 2020 at 15:50
  • \$\begingroup\$ Thanks, will add. \$\endgroup\$ Commented Oct 15, 2020 at 16:16
  • 1
    \$\begingroup\$ Are you sure you are legally allowed to perform mains rewiring in your house? You can get into trouble if the house burns down or someone gets electrocuted. Hire a competent electrician that is legally allowed to perform mains installations. \$\endgroup\$
    – Justme
    Commented Oct 15, 2020 at 19:41

2 Answers 2

1
\$\begingroup\$

If there is a connection between neutral and earth at the circuit breaker box or at at one of them or at the counter, it means that, in your area the neutral is using earth as a return path to the electric plant. So technically earth and neutral are tied together and should make no difference. Except that it does. Having neutral and earth tied somewhere in building is creating interference.

It's also not compatible with differential circuit breakers.

But I do hope that neutral going to earth is the legal way and not the result of a very bad installation by a non professional. The first thing is to check with your electricity provider how the connection (Phases, neutral and earth) are supposed to be. I strongly suggest you call them and explain your problem because there is a serious health hazard here. Ideally having somebody form the electric company to come and check your installation and tell you what you have to do.

The next step will be to install decent yellow and green earth wires at as many plug and light appliances and other things as possible everywhere in the building. And first of all, you need to dig an iron or copper bar deep into the earth to create a earth ground connection. Tying to the pipe is not as safe. In fact it's the pipes that should be connected to earth for safety.

Then check all the supposed neutral wires if they are not connected to earth wires. If earth wires are absent totally, this is easier. But if they run side by side in uncoloured wires (as it was in the old days of the Soviet era), or worse, with not matching colour (then I wish you good luck) then it can take a week or two to sort it out. It's a very big work. But yes, it would be a VERY good idea to separate neutral and earth completely, down to the counter.

The charger blowing up and the related story is possibly because the two phases (assuming there are three phases in your building) have been shortly in contact together. It created a voltage surge which destroys electrical devices.

In other words: Invest in the renovation of the electric installation of the building.

\$\endgroup\$
4
  • \$\begingroup\$ Thanks Fredled. I think I need to clarify here a bit, this is a typical soviet style block of flats. Electricity coming into the flat (apartment as I called earlier) is just neutral and phase. There is no 3 phases here so the story of them meeting together wouldn't work. I'm pretty certain it was the ESD. Either way, there was no earth cable here in the mains, the place was rewired and earth cable was added to each socket, however, the cables were connected to neutral in the cabinet. I have now made removed that connection and instead reconnected to the earth cable going to the basement. \$\endgroup\$ Commented Oct 16, 2020 at 19:38
  • \$\begingroup\$ The estate owner electrician will be here to verify the installation and we will request clarification regarding earthing. For now, the flat and the basement are now both earthed using the same common point (the pipe that I saw had other things earthed to it). Is there a safe way to verify that there is no direct connection between neutral and ground? The cabinet in the flat needs to be redone to remove the soviet style screw fuses and install an RCD which I think is really needed here. \$\endgroup\$ Commented Oct 16, 2020 at 19:44
  • \$\begingroup\$ You must ask the electrician if it's normal that neutral and earth are connected together. Sometimes it is, when the neutral use the earth as a return path to the electric power plant. Sometimes it's not and then it should be fixed, else it can be dangerous and you are still without any earth ground. To verify that there is no direct connection between neutral and ground, you must disconnect all the neutral wires in the cabinets. Keep earth wires connected. Take a multimeter. Select 200 ohms. Test each neutral wire with one probe on the neutral, the other on the earth wire or pin. \$\endgroup\$
    – Fredled
    Commented Oct 17, 2020 at 9:36
  • \$\begingroup\$ It's possible that some neutral are connected to earth in connection boxes, If all wires are white, glue coloured islation tape on them at each end. Check also earth pins in wall sockets by connecting a long wire from the main earth in the cellar, and at the other end you check with the multimeter: one probe on the earth pin the other on the long wire. It can be any wire. Turn off current before proceeding. \$\endgroup\$
    – Fredled
    Commented Oct 17, 2020 at 9:36
-1
\$\begingroup\$

Part 2: Ethernet utilises transformers at both ends so there’s no problem with having somewhat different grounds at either end. Data rates are in the MHz at least so 50Hz AC interference will be far out of band and won’t interfere with data transfer or cause any damage.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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