Question from a non-electrician, so excuse my ignorance. The main fuse holder in my house has just been updated to a new one, owing to my existing one being about fifty years old. How is this done with the incoming cable still live?
A lot of cable jointing is done live, and it can be interesting to watch this if you get the chance.
Some authorities consider that smaller cables jointed from larger ones are the greatest risk. Not the making of the T joint, but any subsequent work on the small cable.
A short circuit on a large cable makes a large bang but should promptly operate the fuses in the substation. A short circuit on a small cable such as the feed to a lighting column may continue to arc for some time as it gradualy burns away.
I once saw an accident resulting indirectly from live jointing. A jointer was doing a routine job with the usual precuations. As the connection was made, a shower of sparks resulted. Some landed in the back of the van on a rag soaked in petrol that had been used to remove bitumen from the hands.
Van caught fire. I did what I could with several large extinguishers whilst someone rang the fire brigade. Van total loss before fire brigade arrived, partly due to explosion of a propane bottle.
A lot of cable jointing is done live, and it can be interesting to watch this if you get the chance.
Some authorities consider that smaller cables jointed from larger ones are the greatest risk. Not the making of the T joint, but any subsequent work on the small cable.
A short circuit on a large cable makes a large bang but should promptly operate the fuses in the substation. A short circuit on a small cable such as the feed to a lighting column may continue to arc for some time as it gradualy burns away.
I once saw an accident resulting indirectly from live jointing. A jointer was doing a routine job with the usual precuations. As the connection was made, a shower of sparks resulted. Some landed in the back of the van on a rag soaked in petrol that had been used to remove bitumen from the hands.
Van caught fire. I did what I could with several large extinguishers whilst someone rang the fire brigade. Van total loss before fire brigade arrived, partly due to explosion of a propane bottle.
