Fuse Holder

Good question Robin, welcome. Others here will be able to answer you better than me. But a few years back we had a couple of older fellas come round to change the fuseholder high up in the front hall. They couldn't remove the old plastic head, so they burnt it off with a blowtorch and then were able to fit the new one, all done live.

Live working. What fun

Live Electric Cable Joint - YouTube



Z.

The answer is 'very carefully'.

A gloved worker will only touch one core at a time, and will have temporary insulation (think little pointy 'wizard hat' shapes  made of rubber) that they apply to exposed ends of cores they are not working on at the time, so the earth and neutral are covered when working on the live core and vice versa. A larger part of the risk is not shock, the gloves handle that, but rather being basted in molten metal if a short circuit occurs.

If the cable is to be cut then there are special insulating wedges and jigs  to drive between the cores, so that the cutting tool stops at the wedge, and only cuts -and the blade only connects,  to one core at a time.

There is a fairly serious training course for this that separates those who can from the rest. (I can't but I have watched..)


It may look agricultural getting the tar off an old fitting and re-terminating the cable ends but the method has been very carefully though out.

Mike.

Yes, it can be done with with proper training and PPE.

As has been said, the greater risk is agruably not electric shock, but a short circuit resulting in burns from both the arcing and from molten metal.


In some cases, the existing cut out and cable end can not be safely worked on whilst live. In that case they excavate outdoors and cut the service cable whilst live, and with proper precautions. A new cutout can then be fitted dead.


If all else fails, then the supply may be dissconnected by removing fuses at the substation or elsewhere. That interupts supply to many other customers and is very much the exception and not the usual way of proceeding.

Thanks for your answers.  "Very carefully" seems to sum it up.

Many years ago I asked a chap from from the Yorkshire Electricity Board (as was) how on earth would they safely splice the supply cable in my front garden while working live. His reply was: "Mr Wombat, the official answer is that our procedures and protective equipment are such that it can always be done safely. Unofficially between you and me, it makes a hell of a bang."

I have watched live jointing under my lawn (normally, nobody, but nobody digs holes in my lawn) and in the street. As Mike says, it is done with insulated or non-conducting tools and a lot of skill. They seem to dig quite a big hole, but I am sure that if you can sit on the edge and work comfortably, it must be safer.

The procedure in holes used to require two out of three items from: insulated gloves, rubber mat, insulated waterproof boots.  IIRC the mat counted even if the hole was very wet.  The hole needs to big enough to be able to safely avoid inadvertent body contact.  These days I think any live exposure requires an appropriate visor too and flameproof overalls.  Thousands of these operations are done each day without incident and its almost exclusively short cuts and unapproved practices that lead to incidents.  There are still plenty of things that have to be done dead.

Now and again you will see a linesman "flying" out of a trench.