Why Did Fuse Blow.

[Ross1]

Hi guys,

One of my guys drilled through a ring main cable today on the 1st floor of a company, knocking out the MCB, RCD feeding the MCB and the BS88-2 fuse in the basement.

Why did it blow the BS88 fuse?

Cheers

 

[Wilko]

Shouldn't have, but did. I'm leaning towards a heavily loaded BS88 fuse popping it's cork. Is that likely?

 

[Rpa07]

Question is - How big was the bang at the drill bit? Did he have to sit down afterwards?
My other question is - did you have a replacement BS88? That is a serious question because, as I'm starting out I am squirrelling away spares like BS88 BS1361 fuses of different sizes for when they are needed either for your/this reason or a call out reason, they will always be around.
Agree with Wilko - if you tested all the BS88's out there I'll bet they pop at different loads (obviously this test would be the end of them but you know what I mean) same with mcb's as we can't test them - rambling now! Cheers

 

[UKMeterman]

Have a look at the energy let through table on this data sheet, https://www.tlc-direct.co.uk/Technical/DataSheets/Wylex/WylexNsMcb.pdf it should help to explain.

 

[Dan]

Have a look at the energy let through table on this data sheet, https://www.tlc-direct.co.uk/Technical/DataSheets/Wylex/WylexNsMcb.pdf it should help to explain.

@Louise some more manuals for you.