cable jointing business

[stuartR1963]

Hi all, in some point in the future I am considering looking into cable jointing. I am sure the pay is great kind and I am kind of looking forward but I also have some concerns.

First of all I understand that most of the time cable joints need to be done live (which I find ridiculous) to avoid inconvenience to customers when joining new/ and or repairing 415v 3 phase and 230v single phase services.

I will get to my main concern, lets say for example I was joining a new service cable from a house to main 3 phase cable in the street, is it true if you were to short circuit any of the phases to neutral or the armor earth (accidentally of course) that the fuse back at the substation won't bat an eye lid (will not blow) and that the short circuit will continue to arc and bang rearranging your face in the process and possibly blinding you.

I am sure when I decide to apply I will get proper years of training and shown the correct way to do it, but is it true that the fuse in the substation won't operate if you get it wrong?. That is just my main concern and is holding me back from applying, the other concern is possible electrocution, but I am sure there will be proper ppe rubber gloves ect.

please share your experience and advice.

thanks in advance

 

[Iggifer]

The fuse may operate, it may not.

Have a look at this video, not a jointing fault, but a nice big bang none the less.

//www.diynot.com/diy/threads/nasty-11kv-bang-on-itv-news-video.449011/

There just is no way to do it dead, that's why there's years of training and PPE. We were talking about this the other day, cable jointing and a linesman are the two jobs you couldn't pay me enough to do. I nearly applied for a WPD apprenticeship a few years ago, but the linesman bit put me off.

 

[stuartR1963]

holy f***, I am scared now, hopefully 415vor 240v won't be as bad as bad as that, and please tell me they don't join 11kv ring mains live as well!?

 

[Taylortwocities]

Mate, you can get killed by a lot less than 240V.

 

[stuartR1963]

I know it can, I think a voltage even as small as 50v with enough current can kill you. what I meant was the arcs and bangs hopefully won't be as bad.

 

[ross94]

It can depend on how far away the cable joint is from the substation,if its a few hundred meters away it will most likely not blow on a short circuit. the substation is fused around 400 to 630amp per phase they are slow acting fuses. It really depends, if the fuse is aged and is tired ,heavy loads from the houses or faults in the past which has put it under strain, the short may just push it to its end and it will blow taking out a 3rd of the street with it.

there will be people on here more experienced than me who will give you a better answer. All I can say is it may or may not blow it really depends, but most of the time I don't think it will blow sadly.

 

[PBC_1966]

I think a voltage even as small as 50v with enough current can kill you..

I believe it's on record that a 32V rural farm installation has proved fatal at least once, although it must have been a pretty rare set of circumstances for that to have happened (person up to his knees in mud, somehow wedged in contact for a long time, etc?).

But keep in mind that while low voltages don't generally pose an electric shock risk, if the source of the power has a low enough resistance, they can still pose other dangers from the amount of power which can be generated into a short. Years ago when I worked for BT I was shown a burned spot on the wooden floor directly below the main supply busbars. It was where somebody in the past had thought "It's only 50 volts" and had become careless, dropping something (I forget what I was told it was now - a screwdriver perhaps, or an offcut of bare conductor) across busbars connected to battery banks capable of delivering thousands of amps into a short-circuit. The result had been an almost instant blob of hot molten metal falling to the floor.

Even something like a 12V car battery can be dangerous in this respect because of the low internal resistance, as a few unfortunate people who have shorted rings on their fingers across one will attest.

 

[Adam_151]

I think you have to decide if you are trying to get into it for the correct reasons; You state that you are sure the money is good, but then give the impression that the whole concept makes you un-easy. Perhaps its not for you.

Of course the folk who do this are trained in the ways of working to enable it to be done safely and the procedures are judged to comply with the EAW regulations, but it does require the individual doing it to trust the methods of working and not get twitchy unnecessarily, etc. I'd hazard a guess that there are folk who start of training for this and get quietly pulled aside told that they are not suitable

Do it if its what you want to do, don't do it because you think its good money


I always find it interesting to watch when its being carried out

 

[sparkwright]

I have to say it doesn't appeal to me.

Stuff the money.

Are you in a situation where you can afford to take the course, and then decide to jack in later on?

 

[Lectrician]

holy f***, I am scared now, hopefully 415vor 240v won't be as bad as bad as that, and please tell me they don't join 11kv ring mains live as well!?

HV underground is always done dead, dead AND the cores earthed down in case it did become live. The HV network and switching is built for redundancy, all the HV kit wired in a ring, but you're able to switch out sections of the ring to work on it while maintaining full supply.

I have seen some 11kv overhead done live, but not sure how common this is.

 

[stuartR1963]

Well, I would say I am quite good and knowledgeable with electrics. I have worked live on some occasions where it is unavoidable. biut just take my time and concentrate and make sure it is correct, but I was also in safe hands that the mcb's or rcd in the fuseboard would back me up if something wen't wrong. I rarely had any accidents and have been quite successful.

I will probably go for it in the end. reading your replies regarding the substation fuses blowing or not, I will try not get to over concerned about that possible risk, I will just take my time and make sure I am doing it correctly and I should be fine.

thanks for the replies

It reminds me a bit like joining the army (never actually did it) the experience in the army I am sure would be great traveling around the world, but there is always that chance you have to go to afgan or something and get killed.

 

[sparkwright]

Up to you. If you fancy spending most of your working life kneeling down in some hole ****ing about with very live electricity.

 

[ross94]

lol, you could work on changing insulators on constantly live 275kv or 400kv pylons in the middle of nowhere. the pay won't be half high for that!.

 

[Screech20]

As said above, the fuse may, or may not blow.
Like you said, don't get overly concerned about the possible risk. You need to learn to trust your equipment and follow policy's and procedures And you'll be fine.
You'll hear horror stories and see things go on, but don't let that bother you, I don't.
If you do the course, who do you intend to work for, a company or for yourself?

 

[EFLImpudence]

It reminds me a bit like joining the army (never actually did it) the experience in the army I am sure would be great traveling around the world, but there is always that chance you have to go to afgan or something and get killed.

You may get killed driving to work - what about driving as a job - too risky?