There are serveral things I (yet) don't understand about the T-T-earthing system. The most important one is that I don't understand which way the the current takes in case one of the conductors (for example L1) touches the chassis of the device.
There are two options I can think of:
a) There is a flow of charge out of the earth at the first grounding, through the Resistance RB, through the coils of the transformator, through L1, through the chassis (at the location of the fault) , through RA, into the ground at the location of the grounding of the device.
There is not a closed current loop. Instead, ground just works like a really big capacitor (with a very big capacity), so draining charges out out of the earth, or putting it in, will not change the potential of the ground at all.
b) There is in fact a current loop in case of a faulty connection between L1 and the chassis of the device, starting at RB, through the coil of the transformator, through L1, through the Chassis, through RA and back to RB.
This would mean there actually is current flowing through the earth (which I find hard to believe since there are parts of the earth that have a very high resistivity.
Which of the two options I suggested is true? Or does it indeed not matter how to model this, because the values of RA and RB can account for the different ways of modelling this?
Edit: I come from another field (physics), and while I have a good understanding about electric potential an electrodynamics, I'm neither familiar with the concepts used in electro-engineering, nor with the terminology. That's where this question stems from.