I have a problem i recently discovered. My home has AC current leaking from all electronics i use. my laptop power supply, my 3d printer, etc..

This was not a major issue until i built my 3d printer. the inductive bed sensor uses 12v directly from the power supply. the leaked current is messing with the sensor readings on the RAMPS board.

Anyway, is there a way I can get rid of AC current leaking into my power supply output ? (12v)

I tested the leakage with a mains voltage live wire tester. all lines (+ve and -ve) were hot. I switch the power supply to UPS only power, and the leakage is gone, so its not a power supply issue i guess. besides, its happening to everything in the house.

I need to mention that i live in a country where there is no earth.

  • \$\begingroup\$ Define leaking. Y-cap to your virtual ground? Are you tripping your RCCB? Can you cheat at use you water faucet as ground? \$\endgroup\$
    – winny
    May 5 '18 at 21:16
  • 2
    \$\begingroup\$ A country where there is no earth? Do you live on Mars? :P \$\endgroup\$
    – Hearth
    May 5 '18 at 21:22
  • \$\begingroup\$ no earth == no ground wiring \$\endgroup\$
    – hp cre
    May 5 '18 at 21:53
  • \$\begingroup\$ @Felthry Parts of Japan, for example, aren't grounded for residences. (I think everywhere in Japan the commercial systems are grounded.) Some places in Europe, I think, may or may not be based upon historical context -- if I remember something I read correctly. And given what I've read for India's local vagaries, I wouldn't be surprised about it there, too. \$\endgroup\$
    – jonk
    May 5 '18 at 21:57
  • \$\begingroup\$ @jonk I know; it was just a joke. \$\endgroup\$
    – Hearth
    May 5 '18 at 22:00

It sounds like either a bad design somewhere, or a ground that's poorly grounded.

Pretty much any appliance with a switched-mode power supply will leak a few milliamps to ground. It's because of the capacitors placed at the front end of the power supply for EMC compatibility. It's totally normal and meets product design specifications.

If your wiring is properly grounded, the voltage on the ground line should still be very low. That can be checked by making a temporary known good ground and comparing with a volt meter. A temporary ground can be created by pushing a suitable metal implement (big screwdriver, garden fork, etc) into a lawn or flower bed. This should be well away from any existing earth rod.

  • \$\begingroup\$ Thank you, this has answered my question. I just wanted to make sure that its proper design to have some leak. Since I don't have ground wiring, i tested with a power supply just now and grounded it to the plumbing pipes. and now no more mains leakage from the positive and negative terminals. \$\endgroup\$
    – hp cre
    May 5 '18 at 22:01
  • \$\begingroup\$ Insert a 10,000 ohm resistor (brown-black-orange) between the power-supply GND and the earth ground. If you measure 10 volts across that resistor, then 1 milliamp is flowing, and that is a dangerous amount. \$\endgroup\$ May 6 '18 at 2:32
  • \$\begingroup\$ When you mention "across the resistor" does that mean between ps gnd and earth wiring? And before or after the resistor? \$\endgroup\$
    – hp cre
    May 6 '18 at 23:54
  • \$\begingroup\$ @hpcre "across the resistor" will be before and after the resistor. A voltmeter has two leads. Connect one to each side of the resistor. \$\endgroup\$
    – Simon B
    May 7 '18 at 17:42
  • \$\begingroup\$ @analogsystemsrf , I did attach a 10kohm resistor and the differential voltage across the two sides was 1.671 VAC. If that is dangerous, then what I do to minimise any risks ? and will there be any electrocution risk on anyone holding the pipes with their bare hands ? \$\endgroup\$
    – hp cre
    May 9 '18 at 9:49

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