MV Cable Extension

Assuming that it is inside the enclosure I see no problem with this.

If it is outside the enclosure, then you will need to ensure adequate continuation of the outer insulation over the separate joints, and also, if armoured, earthing of the sheath.

Also, if it is an outside joint, remember eddy current considerations where the single core cables enter the enclosure, ie. through a single entry hole or ensure a slot exists between separate holes.

Thanks for the prompt response

The proposed joint is outside the breaker panel but within an underfloor cable trench.

If it is difficult to enter the 3 x 1 core cables through a common hole, we shall replace the gland plate with an aluminium plate or bakelite sheet to prevent eddy current heating

My advice is to go for a straight through joint at a suitable location near cable trench . It will be safer and make proper termination to the breaker.

What does your country/ local codes require? Your splices can be as pretty as a flower but if they're outside of the governing code(s) ...... Not knowing what country your working in, you might want to research it a little more before spending time and money doing something that will not pass inspections, or at least that's what I would do to start with.

Oh, damn, I cut the cable twice and it is still too short....

now, do you even have to say that? I mean the guy is already miserable. Cut too short. I'll call it "irreversible".

Yep. Measure once, cut twice.

If the cable has to be longer than the maximum delivered length-even it is a new run-you have to use a joint.

However, 2 m before termination it is not so elegant way to joint it. This point is a source of another possible-

additional- fault [theoretically, at least].

Actually the cable is pre-existing. The fault was in the old VCB panel which caught fire and the cable termination inside got damaged as well. After cutting out the damaged portion, the cable is short by 2m for re-termination in the new VCB Panel. The other end of the cable is 200m long and is buried in the ground with no hope of pulling it up.

Hence we are looking for an out-of-the-box solution.

I have seen HT Aerial Bunched Cables with straight thru joints hanging loose in the air. Hence I felt we could extend the leads by a couple of meters. However most of the people I have asked so far are sceptical. So I guess it needs re-thinking

Check out this image on this link : http://www.tehnosistem.co.rs/str6_eng.html

It seems to me that your own link answers your original question!

Now, whether it meets code in your locality and situation is a totally separate question that must be answered before you proceed.

Finally, make sure that, assuming it does meet code, that the splicing is done by someone fully trained in the use of that particular splicing method for that kind of service. 6.6kV splicing is not for beginners!

So much for the guesstimate! Now, how can we justify our cost over-runs?? Or, is that just cutting things too close

My suggestion: install a 30 ft pole in the appropriate place to install a junction box on the pole for the connection you need, travel up the pole, going through the air and attach the new cable to the building at proper height. Connect the new end where appropriate .

Employ a cable jointer that knows what he is doing. If I had to do this joint I'm afraid "it would be inconvenient" wouldn't be a valid argument.

A trifurcating joint (look it up) is near a metre long.

It can be done by using individual straight joint kits but each cable should be carefully bunched and insulated. Also the straight through joint kits voltage rating should be matched with the voltage level.

Thanks for the confirmation