Paul,

Your situation seems like there is an accumilation of leakage current existing on the remaining circuits, which becomes excessive [over 100 ma] after the Kettle and Stove Elements / Water Heater together are connected.
What I am saying is that there's may be a leakage of 80 ma on the remaining circuits in the house, then when the other loads are turned on [the Kettle and Water Heater, or Stove Elements], their leakages add possibly another 20 to 30 ma leakage, resulting in the RCD/GFI tripping.
This is just a guess, but might be possible [???]. It's a common complaint I have heard when asked to troubleshoot GFCI circuits [when two loads run together, GFCI trips. When run separate, no trip]. The biggest difference between our power system's configuration and yours, there is no "Balanced Neutral", or Multiwire Circuits to deal with in the house. The way your situation is reacting, makes it sound like a Multiwire circuit and GFCI circuit mixup, or some other mixup on the LOAD side of a GFCI device, or an over leakage situation [most likely situation].

Hope that didn't make this message any more corn-fusing than it already is [Linked Image] It's been a very, very long day [and night!] for me...time for bed!

Anyhow, maybe the problem is just too much leakage current, or just a real sensitive device.
Still, those values measured from the Megger are really low! The 200M would result in 0.00012 amps @ 240 volts. If the value was 2M, that would be 0.012 amps @ 240 volts.
The 400K results in 0.006 amps. If the value was 40K, that would push 0.06 amps @ 240 volts. If the lower Resistance values were the actual ones, that would be 0.072 amps - which combined with an existing leakage of 0.030 amps, would be above the maximum imbalanced &/or charging current level of 0.1 amps - causing a trip.

[Linked Image] Man, I can sure talk some bull, huh??? Almost goes in circles!

Lastly, If you want to send me the CAD drawn stuff mentioned in the most recent message, maybe I can convert and post for you. Let me know what you think.

Scott SET

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!