Why?

[diditrain]

Working with a colleague today who drilled through a leg of RFC, not in a safe zone. The 30 Amp 3036 failed to operate, however the BS88 100 Amp service fuse ruptured.

 

[ipf]

My old boss cut through a 6mm, live on a 30A 3036, blew the arse out of his cutters, went and got his other cutters, assumed the fuse had gone, cut it again, another ruined set of cutters and circuit still live.

Still alive ? How did he know ? Pliers knackered too ?

 

[Dave 85]

Funnily enough, the guy used to carry 3 items to check if things were live...
A neon screwdriver
A GU10 holder with a bulb in
What he used to refer to as his 'live cutters'

Im not suggesting he used all 3 in succession, just whichever was closest to hand, this is actually a true story beleive it or not

 

[MarkieSparkie]

If you look at the manufacturers time /current characteristics for both types of fuses you will see that as the time becomes <0.1s (short circuit) the prospective current required to blow both fuses become increasingly convergent. As this ratio of currents becomes <2:1 discrimination is not assured, and this is the reason for their omission from the BS7671 graphs. So either or both fuses may blow depending on the load and characteristics of the installation and it's final circuits.

 

[Guest111]

Here,s 2 for you,a piece of copper pipe in a service fuse,an old spark many years ago had for years tested for live by touching wire with finger and suffered no ill effects until the day he did same trick in a loft and failed to notice the copper water pipe behind his head,apparently as he got in position to test the jb his neck came into contact with pipe,game over I believe the medics had a hell of a job getting his body out of the loft.Still not half as bad as a mate of mine who was an undertaker one night got called out to collect a body in a field when he got there a fireman asked if he had a head for heights,body was on a pylon the bloke shinned down an insulator to get some birds eggs and caused a flashover,apparently the body was cooked.

 

[SPARTYKUS]

^^^^ Jaysus! Just had my tea (spare ribs)

 

[diditrain]

Probably smelt like spare ribs

 

[boberty]

Was doing work at a farm many years ago. Had just started to drill hole through wall by some existing submains, when the boss came in and said he would do it. Didn't think I should in case i went through one of the submains. Needless to say as I was working elsewhere when all the power went off. When we got to where the boss was drilling he was a a bit dazed, half the tip of the drillbit was missing. Turned out that not only had the service fuses blown but also the ones in the pole transformer. opps.