main cut out blowing

[robbie t]

why would a suppliers main cut out fuse an old type 60 / 80 blow . just installed a socket i isolated the whole fuse board added a new socket spur off the ring ,tested R1 -R2 and insulation resistance all expected values .turned main isolater back on at the fuse board and there was no power ....... any idears

 

[telectrix]

terrible state of affairs when work eats into ale time.