Electrical – Understanding ground to earth and neutral, trying to make the home safe

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I've been reading for hours and still confused in regards to my situation. I'm trying to improve electrical safety in my house, especially with a growing family.

Any help would be great.

I'm in Pakistan, where electricians are basically uneducated and there are no codes or regulations.

Current situation:

  • 3 phase meter, 220V.
  • All phases go to a big breaker in the panel, then onwards to smaller individual breakers.
  • All neutral wires come into the panel, are joined together and connected with the neutral wire coming from the transformer (neutral wire is not connected to the breaker panel box in anyway).
  • Ground wires all meet up in the breaker panel and are joined together where then it is run outside and goes into the earth (again not connected to the breaker panel.) So this setup is NOT equipment grounding conductor (EGC,) if I understand correctly.

If ground is not present and I take a voltage tester screwdriver and check the metal case of the desktop case or camera NVR case, for example, I can see the tester light up. There is small leakage of current. This was the sole reason for taking ground wire to earth, tester does not light up then.

Q1. If the hot wire touches a metal case (say desktop), ground is currently only going to earth. What happens then? I am assuming that I would get shocked and breaker cannot trip as the circuit is not complete (no EGC).

Q2. My router for example, only has a 2 plug power adapter (so no ground plug.) With the tester screwdriver I see some power leakage if I touch any metal part. If the neutral wire and ground wire (that goes into the earth) are connected (at breaker panel,) will it prevent this small leakage happening in the router?

PS: I don't understand why such small power leakages occur.

Best Answer

I suggest that if you are really concerned about electrical safety, hire a professional to look at your electrical installation.

You going around with a tester screwdriver and seeing it light up MEANS NOTHING as these testers are very sensitive and light up at the smallest of signals. Capacitive coupling between wires is enough to make it light up. That means an unconnected wire (which is perfectly safe to touch, it is not connected to anything) running next to a live wire is already enough to make the tester light up when you test the unconnected wire.

Also nearly all power adapters and phone chargers can make that tester light up while they're perfectly safe to use. Power adapter also have some capacitive coupling to the mains which these devices need to prevent them from disturbing other devices.

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