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I came across the following circuit on a random website:

phase neutral earth fault detection circuit

Source website

My guess is this circuit is used by some extension boards as shown below:

extension board

I understand that LED1 current (around 2 mA) is flowing into the earth when things are working fine.

My questions are as follows:

  1. Is this an acceptable practice in general?

  2. Will it cause the RCCB/ELCB to trip, assuming someone is using 20-30 such products (extension boards)?

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  • \$\begingroup\$ Actually, the current through the LEDs would be about 230/56 = 4.1 mA. \$\endgroup\$ Feb 21 at 12:33
  • \$\begingroup\$ @MathKeepsMeBusy - i am considering half pulse only assuming negative pulse won't pass. that's why I am getting half of what you got. \$\endgroup\$ Feb 21 at 12:40
  • \$\begingroup\$ Yes, I should have taken that into account. Sorry. \$\endgroup\$ Feb 21 at 12:44

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Is this an acceptable practice in general?

If you mean is the circuit suitable then the answer us a big fat "no". LEDs have a maximum reverse voltage that is at best tens of volts and not hundreds of volts.

Will it cause the RCCB/ELCB to trip, assuming someone is using 20-30 such products

The design is flawed; it will burn first so I'd be more inclined to worry about that than worrying about tripping an RCCB.

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