alternator wiring fire

Hi all,
I need a bit of help with my alternator wiring as it's all gone horribly wrong!
I have a 1983 series 3 with a 200tdi engine. this was done before i bought it and all the wiring seems quite dodgy. I recently replaced the Lucas A127 alternator as the old one was battered. Everything seemed good until I was driving it yesterday and there was lots of plasticy smoke from the bonnet. The 3 wires from the alternator are completly fried and have split in severel places. There are 2 thick wires and a thin one. It looks like one of them goes to the starter motor but I'm not sure where exactly they are meant to go? Any help would be appreciated also what size wire am i meant to use? Thanks

the 2 thick wires are battery feeds they can and often join battery cables at starter ,the thin one goes to ignition light

thanks mate so the alternator and starter motor share a wire to the battery?

yeah i get it now so really I can bypass the starter and wire it straight to the battery? I want to keep them well clear of the engine block thats what caused them to burn

you could ,feed for the car also comes from starter