The fault current doesn't necessarily have to be 'large'. In principle
30 mA will do the trick if the device doing the automatic disconnection is an RCD.Or RCD in some circumstances. (OK "circuit breaker" in its most general sense includes RCCBs, but saying "fuse, MCB or RCD" might be clearer for most readers.)
That's wrong. Touch voltage can be much higher during an earth fault: half-mains or more, due to the voltage drop in the CPC. Shock protection is achieved by limiting the fault duration, not the fault voltage. Only in particular cases is it necessary to provide local supplementary bonding to limit the voltage too.
This is out of date information now. Permissible disconnection times have changed significantly in the 17th ed. and the old distinction between socket circuits and fixed equipment has gone. For 230 V AC supplies (incl. 230/400 V 3-ph) the following maxima now apply:
System TN TT ----- ----- Final circuits 32 A 5 s 1 s Distribution circuits 5 s 1 s
Remember the mantra: earthing protects by reducing the duration of touch voltages. Bonding protects by reducing their magnitude.