Heres a few pics for the photos for discussion forum i took today on a job yesterday, to move a consumer unit onto another wall ( about 1 meter away).
Was under the floor sussing out cables as nothing was marked, and found this J, thought it was long dead.
But my trusty VOL-CON elite told me otherwise. And it never even blew the fuse (rewirable). Little info. 2.5mm T+E leg from a ring main returning to the CU, jointed in a 30A JB. The phase conductor was melted all the way back to the white clip in the pic.
Water must have filled the box as its below the kitchen.