Iv just a an electrician friend (cheaper;)) install a dedicated consumer unit just for my hifi direct from my meter end bypassing the thinner old wiring,I have got seperate RCBO's (does over current and 30ma trip in one) for each bit of kit also fitted a new earth rod with 10mm.
Running 6mm copper in radial circuits this consistently sounds & looks on tv better than ANY mains product Iv ever tried period all wanky wires etc are just out of their legue in comparisson.
Any normal leccy guy will say that 2.5mm twin & earth will run a hifi fine yes it will but it wont lower the impeadence like this does thats what you need to do not constrict dynamics with complications to the circuit the simpler path the better.
Several mates inc my leccy friend have the same MEM CU's in their kit too & no mains filters make any difference apart from degrading it as demonstrated when I briefly tried a PS audio P500 wich made my mates cd player sound slow via his dedicated line & no better on my old mains ether!
The cost mine was £300 ;) thanks mate but could differ depending upon who installs it.
JUST TO ADD DO NOT TRY TO DO ANY WORK ON MAINS ON YOUR OWN THIS WAS DONE BY A PROFESSIONAL !
The results a massive soundstage a blacker background Iv heard things that where not there before stuff like Floyd sounds superb the volume control can be pumped up a lot more without congestion or going brittle at the topend,oh the bass depth tightness and control are exemplary as are the mids too little outlay for BIG gains not a hifi wanky ad in sight MEM will start been in hifi ads soon
I guess the critics will poo poo my post now saying this dont or cant work you should hear it it does!
Feel free to PM questions that I cannot reply to,to keep within this forums rules thanks.