I did a board change a couple months ago - everything hunky dory.
Got a call back to same house last week, asked the guy what was wrong. He said the shower wasn't working. I asked what actually was happening with the shower?
"Some smoke" was the reply.
A "friend of the family" had changed the guys shower since my board change.
Cover off, the neutral was black instead of blue.... crispy and brittle insulation. A little tug and it just falls out the terminal block. Same with the c.p.c.
Pulled spare cable out the wall, new bit of block, reterminated, tested and everything good again.
Sorry, no photos. But it shows you how easy a loose termination can start overheating, and may, in the right circumstances, cause a serious fire.