UK Power Networks, hot working

Yes, live working is common, though not universal.

New or replacement service cables are usually live jointed to the main in the street.

Renewal of an existing service cut out is often avoided whilst live. It is common practice in such cases to excavate outside the premises, cut the service cable whilst live, renew the cut out, and then live joint the service cable to restore the supply.

When we had our meter and service head (cut-out) moved, the pilc cable was cut and a length of split-con from the new cut-out was joined on. All whilst live.

I have also witnessed a cut-out being replaced - like for like with the plastic type. Quite amazing to watch, since the location and access was poor.

Both these jobs in the old MANWEB area.

Clive

Not UKPN area, but in SSE territory where we work, when a service head replacement was needed, they did as described above, cut the service out live from a pit outside the house, but then TNC-S'd it (PME) because that's the policy in that area because of deteriorating u/g cables, and replaced it with a bit of cu/al concentric to the new cutout. Ze improved remarkably

In the old Wessex region of SSE it would depend upon what type of service head and cable they had in the van at the time as to what you got, a great deal of the jointers didnt have a clue, about the difference between cable sheaf and pme. ( I know I used to work for them).

So I take it they cut/connect Line & neutral cables separately to avoid them from touching?


Does anyone know of a video showing ukpn doing this?


Thanks for your replies guys.

Although not a video, there is a very good blow by blow picture book tutorial in

The UKPN jointer's handbook.

It is big, because of the pics, and you need to subscribe and verify your Email adress to download it, in about 5 parts.


Subscribe here login/reister page



Then do an all category search, for "LV" only works if you are logged in.

Top matches....
https://g81.ukpowernetworks.co.uk/search?category=any&doctype=any&Phrase=LV&Page=1



I presume your interest in insulated hacksaws, core separating wedges etc is academic! Do not be tempted to do anything silly.


Round here they can replace a cut out onto live ends, but if the cut out position needs to be be moved, or there is reason to suspect asbestos in the cut out, or the end of the cable is damaged or too short, then the standard method is to cut outdoors and bring a new tail in - any join nearly always has to be outdoors as the joint is about 2 ft long and 4 inches in diameter.

A very interesting read. Thanks for the link and download instructions. Some pictures make me think (again) how much more "expressive" the old colour-codes were - prettier, too. 


The work on cutouts in a confined space sounds a little hair-raising, particularly if the pscc is more than one or two kA.

Indeed, but if the rules are followed, there is no time when both L and N are exposed, clever things are done with 'wizard hats' of site applied insulation and spacers, so when L is bare, N and E are covered, and vice-versa.

I remember seeing a couple of guys changing the head in the house next door. They had trouble getting the cable out of the old head, and ended up burning it off with a blow torch. All done live, or rather hot.

So I take it they cut/connect Line & neutral cables separately to avoid them from touching?

I watched (what was then) YEDL replace a 3-phase cut-out live. Basic procedure seemed to be disconnect one wire, then put a temporary sleeve over it, before moving onto the next. Reconnect in reverse as it were, so at any point in time there's at most one bare live end.


When splicing in to a live main, I think neutral is never cut (lost N is a bad thing on any 3-phase system, let alone a broken PEN) - they even have designs of cables that have a little extra length in the "armour" (N/PEN) wires so there's enough slacks to they can be pulled away from the cores without cutting them.


   - Andy.