when looking at table 2a 7671 on site guide, the value stated for earth fault loop impedance using a bs 3036 fuse 45 amp with a protective conductor of 2.5to 16.0 is o.50ohms. now then at the begining of the guide it states the following Ze values
TN-S system 0.8ohms
TN-C-S system 0.35ohms
TT system 21 ohms
does this then mean that the 45 amp fuse can only be installed in TN-C-S systems due to the Ze values in the other systems are already to high without even taken in to account the circuits cpc?

this goes for all the stated values lower than 0.8ohms using other types of fuse.