Main fuse blows before MCB.

[Deleted account]

Are you sure that it was the main fuse. Chinese whisper.

plumber tells customer - customer tells you-

did the plumber tell customer correctly
did the customer understand correctly
did the customer tell you correctly.
did you….you get the jist…



My thinking it was the switched fuse that blew not the main incoming, but terminology got mistranslated down the line.

 

[Bobble23]

Thanks all. To be honest Paignton Pete you might be right, though he did say they were rummaging around in the cupboard with the main cut-out in it. Either way interested to read pc1966 and how it's not quite as cut and dried as MCB always trips first, main fuse second. Always something to learn in this job. Mainly to keep away from plumbers.

Thanks again.

 

[GLENNSPARK]

Mcb's are resettable....fuses aren't...
Every time you subject a fuse to fault, it's going to stress it...

Assuming it was a KMF you fitted...
These typically come with an 80A BS88 which won't necessarily provide you with discrimination between 80A & 100A...
(assuming it was a 100A BS88/BS1361 in the DNO's cutout anyway.....could've been as low as 60A)