wiring help

ive had an electrical fire in my 1990 defender 90 an some of the wires are totaled i have a wire behind the clock in the middle when i traced it back was a thick white wire can someone tell me what this is for an also the wires to the battrie meter in the main dash could you tell me what colour they should be as the wire that is conected to it looks like it was retro fitted by the moron who left the live wire to ark at will an cause this mess
cheers in advance

all white wires are ignition live ,feed to,switches/fuses ,as with brown wires they are all linked ,brown wires are battery live

thanks jamesmartin so should it power the 12v cigarette lighter or something else ?????????
cheers

probably battery meter if its thick

no this wire is in the center space not behind the dash it does seem a a tad big just to power one of (clock ,rear screed wash wipe ,or cig lighter )

the big white wires are usually behind dash or to fuse box below,i thought he may have used one as you would want ignition live for battery meter