I don't recall a BS for "oops extension pieces" (to mis-quote Starrett's oops-arbors) - in which case 511.2 is probably the way to go.

In the first photo it looks to have been installed at a bit of a jaunty angle though  ... which might make me suspect that the extra lengths involved are acting as a lever and putting more strain on things than would ordinarily be the case ... which if can't be corrected would make me wonder about 134.1.1 (Good workmanship .. and proper materials).

   - Andy.

Normally on smaller cables one uses a short length of the same size conduit as the gland hole to do this, much as one would for pyrotenax cables. Modern way seems to be to waste a length of metal trunking and use a few inches  of it or have an adaptable box with nothing in but the cores and a bit of wiggle length.

However, as this stuff is presumably about 3 inches in diameter and the glands will look like soil pipe fittings, so perhaps not at this scale.

So, first how well does it make electrical contact - would it handle the full PSSC?

Then, does it satisfy the environmental requirements of the location ? - looks not to be IP anything but I don't think the bare gland was IP44 either...

Third, Is it putting an excess strain on the gland plate or box ? - if so the cable fixings may need revisiting.

So probably could be OK, if done well, but of that we need to be confident.

Oh, also, why is there  a machine screw sticking out the side ?

Mike.

Michael MacMillan said:

We have some reservations accepting the installation, therefore I am seeking some clarity on the following points:

• Is this an acceptable installation method under BS7671?
• What specific clauses in BS7671 would these pieces have to conform to (511.1?)
• is there anything in the Regulations that would allow this installation to be rejected?

The IP rating that could have been achieved by the original gland is now, sadly, not achievable.


Are there any prevailing environmental conditions? Is corrosion prevention suitable?

This kind of question is really difficult to answer accurately without seeing it "in the flesh" because we have no context, especially with such limited snaps.

At the end of the day, I'd be worried about the ongoing continuity of the SWA connection to PE - which it will need at least at one end (for safety, extraneous-conductive parts definitely here) but also perhaps to control touch-voltage at the other (or for other purposes).


Also, from experience ... are there any other contractual requirements that might not be met ?

Aside from all that ... the "fix it r" option at this stage may well be a potted junction to extend the cable (depending on lengths of run) ... which might prove a nuisance in the future.

The oops arbors look good for folk like me who sometimes  cut twice and measure once.... or something like that. Thanks for pointing them out, I was not aware and originally thought you were joking.. No use to the original post of course, but now I know what I need for Christmas. Sad isn't it.

Mike.

My guess is that the set screw is there as a kind of earthing stud to bond to.

earthing stud to bond to.

And if so, on a circuit with 240mm2 conductors it looks woefully under-size for carrying the sort of PSSC one might imagine.

What is it - M4 perhaps ?  M12 or perhaps M14 would be more like it.
Unless it is something odd, like a 10km run for a voltage drop compliant supply to a single 13A socket of course. But I think we can assume not, and at 0.2 ohms per km, guess at something in the region of a 400- 600A supply with a few % volt drop, and then a PSSC of 20kA or more is quite credible and should be allowed for - hence my concern about the current handling by things that just hang on by the threads where it meets the box and the gland. (the armour is probably made of 90 or so  2mm dia or 60 or so 2,5mm dia steel wires, and the cable will have a 1 second withstand of at least 30kA. To preserve the rating that sort of steel cross section needs to be in the extension too.)

M.

"5 core" cables suggests one core as the earth, together with three phases and a neutral. If this is so, then an earth core reduces concerns about the fault current withstand of the extension pieces.

Thank you all for the responses so far, very helpful.

For further context, there are eight 5C, 240mm2, SWA cables in parallel - TPN+E each.

Only two of the cables have been made-off too short and fitted with these extension pieces.

The small stud visible is an M6 connection for additional earthing, along with the cable gland earth tag, and the gland-plate earthing.

The installation is on an Island in Scotland, and has been deemed as a C5 Marine Environment (highly corrosive), therefore I share the concerns of ongoing reliability of the earth continuity between the Gland, Adapter and Gland-plate.

The cable gland manufacture has confirmed the gland is capable of handling the full PSSC, but i have aske the Contractor to provide confirmation via calculation that the adapter piece can withstand the full PSSC.

I will also challenge on Clause 134.1.1, given the other six cables have been made off properly.

Many Thanks!

One more thought to add to the mix - what's the conductivity of 316 stainless steel like? (I've a feeling that SS is often poorer than plain steel, which in turn is poorer than brass or copper) so it might run a fair bit warmer under fault conditions than an equivalent conduit coupler for instance.

   - Andy.

Yes, the conductivity is only about 20% to 25% of low carbon steel; and 2.5% of copper.