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.

 

[greengrass66]

If all power was not isolated e.g lights, heaters then it might not have taken more than 30a of fault current to blow the 100a main fuse.

 

[telectrix]

ah , but these clever little 3036 fuses were programmed to only blow on a shorted cable in a safe zone. hee, hee.

 

[mechelec]

Wrong size fuse wire/nail used in carrier or aged main co fuse

 

[sedgy34]

Wrong size fuse wire/nail used in carrier or aged main co fuse

agreed the old nail scenario

 

[PC Electrics]

Doesn't really surprise me tbh. 3036s? Might as well be nails!

 

[markthespark]

I cut through a live 2.5mm cable in a loft once and it blew a faulty joint under the street! Bypassed the 30 amp 3036 fuse and the 100 amp cut out.

 

[diditrain]

No, nails were definately not in service

 

[plugsandsparks]

Might be worthwhile renewing the wire though as it has had to deal with a bit of a shock

 

[sedgy34]

maybe that main fuse was down to its thread anyway and popped first, it may have been older than our dinosaur friends on here lol

 

[Strima]

The paperclip in the BS88 wasn't of the correct rating.

 

[boberty]

Paperclip! More likely tobe foil from a cig packet if its that old

 

[Des 56]

Which fuse modification is best I wonder

Does tin foil from a smoke packet have the ability to withstand higher fault currents than the paper clip ?
What about the 6" nail,is it able to discriminate with the foil, surely the sequence should always be

Foil in the plug top,paper clip in the fuse board and a 6 " nail for the meatier supply fuse,anyone think differently ?



The history of these fuse adaptions is also varied according to the Wiki site

Foil is getting much easier to obtain with the advent of the roll variety,especially for cooking the bacon,it was rare at one time,found only in Woodbine packets

Paper clips were possibly only made of wood, so have no real history,especially when compared to the 6" nail, which along with its use as a service fuse,was found to be ideal for making wood stick to other pieces of wood,but its original service fuse use will continue until a better alternative can be found

These adaptor items have been known to save on possible costly and usually un justified employment of electricians
With the demise of the trade,its probable,fuse adaptors and their use will continue to flourish

 

[Dave 85]

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.

 

[Dave 85]

Another one Ive seen is an open backbox with a 6mm in a TB filled with wet plaster, someone complained it was smoking while the plaster was drying out. When I went to the job all the clips holding said 6mm to the joist in the garage appeared to have melted, circuit still live. Both occasions the fuse had 30A fusewire in it.

 

[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.