Today I turned on my water boiler, and all the lights in my apartment turned off. I opened the electricity box and saw the RCD was tripped. I turned it back on, but then it would trip again whenever the water boiler was running.

I cursed my luck because I figured I have to fix my water boiler.

I then turned on the drier, and after a few seconds the RCD tripped again. I turned the RCD back on, and later turned on the AC. After a few seconds, the RCD trips again.

Right now as I'm typing this, the RCD isn't tripping and the electricity is on, but no high-wattage device like the above three is running. Can I conclude that high wattage is what's causing the problem? Maybe the RCD is faulty and I need to replace a fuse or the entire thing? Or maybe the problem is entirely different? I'll be happy to hear your thoughts.

  • That's strange! How many phases of service (1, 2, or all 3) do you get, and is the RCD a main RCD on a single set of breakers for the whole house, or are things organized using multiple consumer units? Commented Jul 4, 2018 at 22:27

1 Answer 1


Somewhere in your electrical system you have leakage between neutral and ground.

All neutrals are connectd without fusing, so the very small voltage on neutral reaches all points in the neutral system. Current follows all paths in proportion to their conductivity (1/resistance) - the regular wired neutral is the dominant path, but some small amount of current uses the leakage between neutral and earth, and when your load is high, that current exceeds 30ma and SNAP!

  • Thanks! How do I find where it leaks?
    – Ram Rachum
    Commented Jul 5, 2018 at 6:26
  • @RamRachum look for current flow on ground wires. Commented Jul 5, 2018 at 16:25

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