There are fuses in the ring main units, I'm not sure if you use these down south but these ABB units are extensively used in the greater Auckland area.
The first switch of the bank is the isolator. Second cubilcle is the metering CT's and VT's. third is switch fuse with 50 Amp fuses. fourth is switch fuse with 80 Amp fuses. fifth is switch fuse with 125 Amp fuses.
I haven't seen 200 Amp ddo's and the end of this line is probably unable to supply that load anyway.
[This message has been edited by RODALCO (edited 02-28-2006).]
The product of rotation, excitation and flux produces electricty.