ELCB Tripping

No, the 4P ELCB (RCD) will not trip when connected with no neutral and an unbalanced 3-phase load. Under this circumstance, the phasor sum of the three phase currents will still be zero, and so the ELCB will detect no residual current to trip on.

Remember to make sure that the two poles that the test trip button works on are connected to phases, so that the test trip works.

I dont agree with you.....its sure that the elcb will trip if one dont connect the neutral as the elcb will not see the return current thru neutral.........It will trip on unbalance load also if the unbalance current is more than trip current rating of elcb even if you connect the nuetral.

Reading the OP again, I concur with Giri. Since there IS a neutral, the unbalanced load will cause neutral current which, since it will not be seen by the ELCB, will look like an earth leakage fault and so will trip the ELCB.

Came across an ELCB Tester. Hope it helps.

http://www.industrialindia.com/catalogs/Digital_ELCB_Tester/Digital-ELCB-Tester-KM-1812EL.pdf

Dear all,

If the battery charger is connected between line and neutral, the load current to the charger is seen as earth fault by the ELCB, thus the ELCB trips. If the battery charger is connected line to line, and trips, it may have an earth leakage in the charger.

Regards