I posted my findings not for the benefit of being told how to do or not do something.
I may not be a registered electrician, but my knowledge of electricity and wiring standards is far better than what I have seen done.
I have 24 years of experience with electricity, so I know my TT from my TN-C-S (and missing neutral issues), my single phase from my three phase, my cable sizing etc. Heck, I told City Power about the voltage issue I described a week before the actual fault showed up. I told them to check their transformers etc for the cause.


In answer to the questions:

The house and the garage DBs are independent of each other. Wiring runs as follows (large property):

METER DB FEED TO MAIN DB (NEXT TO METER DB AT THE SIDE OF HOUSE)

MAIN DB [NO E/L] FEEDS
(1) SWIMMING POOL DB
(2) HOUSE DB
(3) GARAGE DB
(4) BURGLAR ALARM FLOODLIGHT SYSTEM [ONLY SINGLE PHASE BOARD]
[1-4 ABOVE ARE E/L BOARDS]

(1) FEEDS ADDITIONAL WORKSHOP D/B
(2) FEEDS ENTERTAINMENT ROOM DB AND BOREHOLE DB
(3) FEEDS STAFF ROOM DB


My use of removing the earth was to confirm 100% that the element is faulty which it has, and also to try to find why it would trip at certain voltages and not others.
I don't possess an insulation tester, as mentioned I am not an electrician as occupation.

The stove doesn't trip when using any of the plates, the warmer drawer or when using the grill option (top of oven, dual element).
Only the normal bake oven trips the power. So it must be either the new bottom bake element or the smaller of the two on the top element (around 20 years old).

As stated, the element doesn't trip consistently, so difficult to run it to see which on trips. Hence disconnecting the earth wire. This showed up the leakage to the chassis. On disconnecting the bottom element, the leakage disappeared.
PROBLEM SOLVED (also eliminates the top element as there was now NO leakage with it still connected).

I forgot to mention, on switching the oven on (without earth), the leakage shows up immediately, but at a much lower voltage (8v or so). it gradually rises as the element heats (obvious). BUT touching the earth to the chassis causes no trip 90% of the time, even when reading 115v chassis to earth. I tried touching it back 10 times, and only once did it trip. Did this mostly out of curiousity.

Yes removing the earth is not recommended, but I can tell you that the appliance was still on earth leakage, and also that no on else was allowed near the thing, even pets. I am very careful, excessively so. There was no risk to me at any point. No touching the chassis, no touching any of the wires directly.


Regardless of what you think, I can guarantee you the element NEVER trips at 220v or below. Any voltages above that and it will start tripping. If you don't believe me, you are welcome to the element to conduct tests. Collect from me in Randburg.

Why I posted this in the first place? To let everyone know that such an odd situation can arise. Not to find the problem. I've done that.
Also not to be sermonised on my methodology.
Remember, I didn't correct your incorrect use of it's (abbreviation of it is) vs its (possessive) and there's (there is) when you mean there are, i.e. as a plural.