If you're quick enough with the megger after the RCD trips, you will see a rapidly increasing resistance. The resistance when measured cold is orders of magnitude higher than when the hot element trips the RCD. Presumably caused by the element moving by expansion/contraction.
On the type of elements we are discussing, the live and neutral terminals have a foot or so of element between them, so L - N shorts aren't normally possible.
I was around long before RCDs, and it wasn't at all unusual to see holes blown in the outer sheath of these elements, or even severed completely.
On the type of elements we are discussing, the live and neutral terminals have a foot or so of element between them, so L - N shorts aren't normally possible.
I was around long before RCDs, and it wasn't at all unusual to see holes blown in the outer sheath of these elements, or even severed completely.
