strange t&e cable damage

M cebee

looked at a problem today

short-circuit on a 6 amp lighting circuit

unfortunately the circuit is wired using inaccessible junction boxes and the cable also is mostly inaccesible

i noticed that the earth sleeving at the DB seemed to be burnt .I stripped the t&e back a good 2 feet and
the brown and blue core insulation
seems to be burnt off-but no externsl sign of damage

wiring is newish pvc t&e
neutralized
all mcbs
no rcds/rcbos fitted

i thought maybe lightning or fault current/return current from another circuit.

any ideas?

i'll be going back after the christmas when hopefully cable runs and joints will be more accessible

Stoner

slightly obvious suggestion, but did you consider a cable manufacturing fault, as you know they do happen, tests are passed then under slight load over time the fault develops, poor insulation gives way and the burning develops masking the cause.

M cebee

thought about that alright
the burnt earth sleeving in the board is strange

Bruthal

Is the copper discoloured? It could have been a bit of cable previously overloaded when used before this installation.

M cebee

robbie7730 wrote: »

Is the copper discoloured? It could have been a bit of cable previously overloaded when used before this installation.

could be-i'll try to post a pic
i was a bit confused by the damage along the length of the cable