LV fuse replacement safety

Standards overseas are politely described as flexible.

Inserting a good quality HRC fuse into a live circuit is FAIRLY low risk, though PPE should be worn for larger fuses, or when large fault currents are involved.

Would I wear PPE for inserting a 32 amp fuse in a control panel ? probably not, ordinary workwear should suffice.

Would I wear PPE for inserting a 100 amp fuse in a factory ? Maybe, it would depend a bit on previous history and on distance from transformer.

Would I wear PPE for inserting a 315 amp fuse in a substation ? Yes I would.

With large open wire fuses, or HRC fuses of doubtful quality the risks are serious.

Five and a bit decades ago Father taught me that a fuse should never be replaced without first having ascertained why it blew in the first place.

If the fault has been corrected, ideally replace off load.

Unfortunately, in some parts of the world, life is cheap.

The value of P.P.E.

Arc flash video…..

Arc Flash Video: When Increased Work Task Risk Level Not Recognized - Bing video

I do not like people nearby to me when I am trying to concentrate on a challenging task, like in this video. They can be distracting by moving about and talking. They can change the lighting level on the work being performed by casting shadows. Basically they should f off and leave the guy working alone to concentrate on his work.

I saw a sign on an old bus once, positioned just behind the driver. It said passengers should not distract  the driver when he is driving. In other words shut up and let him concentrate.

Z.

Kelly, I prefer to turn off via a main switch before removing any fuses. The new ones can then be inserted dead. Any covers of equipment can then be put into place or door closed. Afterwards the main switch can be turned back on again. Any explosion can then be contained within the H.R.C. fuse itself or within the equipment.

Weird robot voice explains the parts of an H.R.C. fuse.

HRC (High Rupturing Capacity) fuse - Bing video

Z.

I assume Kelly refers to this video. 

He does actually turn off the isolator  built into the transformer, and as he uses a neon indicator to check for live when he has finished, I presume he has the option of using it to check before he starts as well - we do not know how the video has been edited.

I agree it is careless and as an educational video likely to cause more problems than it solves.

The sheer weight of wire tangles around those horns suggests that those  fence wire ‘LT fuses’ blow quite often, and no one ever removes the old stuff. He seems a bit unsure about 1 strand or two in parallel per phase.

India is on my list of places where the normal rules of the game do not seem to apply, having been out there for work on a couple of occasions. I do recall in the supply to a clinic looking up at the HV feed to realise there was a splice (like you might do in a rope) with loose ends sticking out like a hedgehog, swaying about merrily in mid span on one of the phases, and on another occasion there was a hotel meeting room prepared for a conference, and to get power to the tables for the guests laptops, phone chargers etc (imagine a layout like lots of tables to watch a cabaret ) strips of carpet tape ran zig zag from table to table and at each intersection a pair of red and black singles emerged from a slot in the tape into a twist and tape joint for a 15A socket…

With transformers on the ground and open, for a while that country held the prize in my list for dodgy, much worse than the former eastern bloc. Then I went to South America for a while, it is fair to say that India is now in 2nd place.

Compare that with practice with Finnish 20kV live working on overhead lines, but more carefully. Note all those shorting links on the HV side before he goes near the transformer. 

Probably still beyond the pale for the UK, but quite safe when done well.

We should not mock really.

It is not that long ago that we sent little kids up chimleys to clean them.

Young kids climbing under moving looms.

Unguarded machines, belts, pulleys etc and loadsa people badly injured.

But the rich elite still made shedloadsa money.

Along came the naughty unions and called for better conditions, oohh how evil those unions were!

Those untidy Indian wires make even some of my less than perfect efforts look pristine.

Sing song……

I've watched the video again and your right there seems to be lots of bits of old wire left behind  i assume that he was told to get the supply back on as fast as possible this time round although I'm sure that eventually they have to clean up the installation get rid of the old bits (burnt offerings). There is another video of him replacing the HT fuses that's even scarier he's inches from live 11KV  lines with bare feet standing on a metal TX. Finally would anyone like to buy a kitten? The health and safety guy just had a litter

I did a job recently involving live testing. I did a loop impedance test and turned around to write the result down to see a Rhinoceros standing 500mm behind me watching what I was doing. Would have made a good training slide but no photos allowed in the non-public areas.