The chock block is actually joining two twin and earth cables. You can see the two neutrals, but the earths and lives seem to have 'become one' in the photo.
The earth terminal block has completely melted.
This was an attempt by some sparky to split up a a single large flat into two smaller ones. He fitted a new fuseboard, and split the circuits best he could - splitting one by joining it in the old CU. He had two individual DNO supplies within a single fuseboard - Very dangerous.
The neutral supply for one of the flats was lost - most of the flats share a TP UG incommer, but the new additional flat created was fed overhead from a pole, as this was more convenient by the looks of it. It was this neutral that dropped. As the spark had not split the circuits very well, he still had lighting circuit earths joined together in places, and again, had two circuits from two different supplies in some joint boxes where he had done the splits, but commoned the earths. As the supplies where all TN-C-S, with the lost neutral, all the current from one flat went sailing down the earths that where common to the flats.......in this case, the lighting circuit was the best route. There was a fair load, as there was no central heating in the new flat.
We have had to strip out both lighting circuits, and rewire them completely. The spark actually did manage to split the socket circuits ok. I guess he bodged with the lights because he could not get above the ceiling.
I should have taken more photos of the damage, as it was not just limited to the terminal block in the CU.
