On Thursday, 23 July 2020 03:13:06 UTC+1, The Natural Philosopher wrote:
On 22/07/2020 22:15, Harry Bloomfield wrote:
tabbypurr formulated on Wednesday :

Tripping at switchoff happens if the element (or other leaky bit) has
its neutral switched off before its live. Element is most likely -
test its insulation.

That may need a meggar to be certain to find the point of leakage.

I've found that a few kohms is enough to trip. Not megohms.

30mA at 240v implies 80k ohms. So as long as you cann detcet less than
that, you are OK

In my case a motors showed around 3kohm with some sort of internal
winding to armature short

Insulation breakdown tends to be very nonlinear with voltage. Multimeters pick up a lot of failures but not all.


NT