Dear Trumpy,
Thanx for assuring me the support.
Frankly speaking - the orgin of the problem is as follows.
One silent night it so happened that in the switchbox(TP MCB +RCCB,30 mA) feeding to a 3 phase load there was a spark and simultaneously there was a blackout because of tripping of main breaker.On further investigation we found that :
1.Below the switchbox embedded in the wall was a loop-in box of only 3x3 size whereas the incoming feeder cable was 16 sqmm 4 core.
2.Needless to add the big size cable was all crumpled inside the small loopin box ,the cable was severely under TENSION and was rubbing against the male bush(GI) and over of period of time the cable insulation was getting damaged.
3.Now in the absence of earth leakage protection ,the insulation continued to get weakened /skinned and finally the fault developed into a phase to phase fault.
4.This accident has forced me to sit down and think about providing a earth fault protection at the mains incomer,but I need a mandatory regulation to prove my case (if I am right).
I am sure incidences of this sort happen once in a blue moon and is sure an installation mistake - cause I feel,had they used a bigger size loop-in box the cable would not have been in tension.I was intending for a earth leakage relay of multiple sensing current and time settings.
Please advice.
