btw - uninsulated tin cable in new enet has fibre-like properties 
anyway i would change fibre for silver - receipe can be unchanged - but it wiuld be good for the sake of rationality to call it silver cable.
GOLD - actually gold is very good electric conductor - and i would suggest making it a little worse than copper
Apropos aluminium - this is way better idea than tin cables actually - aluminium is about 2 times more lossy than copper, so is the tin cable in current setups- I would make this somewhere between tin and copper, and with aluminium requiring more energy to create( liquid salt electrolisis = lots of EU + machine) i would make it between tin and copper for energy loss but capable of 512 eu and require 2 rubber as gold cable 
That would make it pretty good material for use apart copper and gold as it will be neither of them - depending on use.
so :
fibre(silver) : 0.025 eu / block - no electrocuting - 8192 capable
copper : 0.06 eu / block - uninsulated - 0.16 - electrocuting 128 eu capable
gold : 0.08 - uninsulated 0.18 - electrocuting - 512 eu capable
aluminium : 0.1 - uninsulated 0.2 - electrocuting 512 eu capable (with 3 rubber 2048 eu capable ? )
tin : 0.18 - uninsulated 0.28 - NOT ELECTROCUTING - 32eu capable
iron : 0.25 - uninsulated 0.35 - electrocuting 2048eu capable
and btw - is there a way to make fibre cables glow proportionally to conducting current ?