Light switch - loud pop and charring

fenwick458

normally if RCD protected you short live and earth out you get a tiny spark and the RCD disconnects. that amount of black charring is only possible from Live-Neutral shorts if protected by an RCD, or if unprotected then yeah a Live to earth fault. 
have to wonder who wired that consumer unit up like that, it obviously newer than 2015 so would have come with 2 RCD's but only one has been fitted?
OP are you sure the RCD works and is actually wired up, if you turn the RCD off do the lights go off?

Risteard

fenwick458 said:

normally if RCD protected you short live and earth out you get a tiny spark and the RCD disconnects. that amount of black charring is only possible from Live-Neutral shorts if protected by an RCD, or if unprotected then yeah a Live to earth fault. 
have to wonder who wired that consumer unit up like that, it obviously newer than 2015 so would have come with 2 RCD's but only one has been fitted?
OP are you sure the RCD works and is actually wired up, if you turn the RCD off do the lights go off?

An RCD will do nothing to restrict the fault current though, but only the duration of the fault.