Did a bit of digging today.

[Bobster]

Anyone seen a joint like this before? I certainly haven't.

400mm 3core going into it. 6 x 630mm singles coming out (2 per phase) @11kv

Found a short to earth on two phases.

 

[Knobhead]

It’s an 11KV trifurcating joint.

Will try to find the details of why there used now, it’s down to how switchgear manufacturer make the terminal boxes for single core cables only. I’ve got a PDF of the methods and standards.

 

[Bobster]

Never seen one like it before. Almost looks like its been a home made job. Fibreglass filled with tar or pitch.

Will be spiked on Monday ready for the jointers.

 

[Knobhead]

Have a look at http://www.sppowersystems.co.uk/newconnections/pdf/CAB-04-009%20Issue%202%20-%20Policy%20&%20Application%20Guide%20for%2011kV%20Pol.pdf

 

[Knobhead]

Have fun spiking the polymeric cables.

The lecy boards have had trouble with them, the spike fires in OK, now try getting the bugger out! It grips the spike.

 

[Bobster]

I've had to spike quite a few de-commissioning a substation on site. I diddnt have too much trouble with them... Was a lot more difficult inside the cable trenches. Not to mention having to fill in confined space permits and special risk assessments.

 

[Knobhead]

Just been thinking about this, 400mm in and 6 x 630mm out? Seems a bloody funny set up to me! I can see the singles, but 6 of them?

 

[ACDC]

Wow, that is a impressive joint! wish i had opportunities to get involved with HV. espeically the spiking part

 

[Bobster]

It is a funny set up, was peiced together from what was already laid. As for 6 coming out as you said earlier it's how the terminations in the switch gear is set out.

Ill get more photos on Monday if you wish of the switchgear or of the joint as a lot more has been dug out.

 

[rfears]

Call The Time Team? :wacko:

 

[Bobster]

Call The Time Team? :wacko:

Felt like someone from timeteam digging round the singles with a trowel.

Was lucky really there are 4 of them joints right next to each other and the thumper only gives a rough location of the fault.

 

[Engineer54]

I thought i could see evidence of another similar joint in your photo's. Those thumpers normally give a pretty clear indication of where the faulty cable is...lol!! So are you involved with the cutting out this exposed joint and replacing it with a new one?? ...Fun and games that should be...lol!!

I'm sure others, like myself would very much appreciate a photo or two of the new joint prior to being filled, ie...showing the connection arrangement(s) between the multi core and single core cables etc...

 

[Engineer54]

Have a look at http://www.sppowersystems.co.uk/new...- Policy & Application Guide for 11kV Pol.pdf

I don't think some of those joints shown in this guide are up too much. I like to see a good 4 to 6 inches of adhesive heat shrink going back onto the cable sheath at each end, especially when being direct buried, rather than just a couple of inches shown here...

Another thing i noticed, there doesn't seem to be any armouring on these HV/MV direct buried cables, only the copper screen. I'm basically used to seeing the screen around each of the cores of MV multi core cables, in the form of a thin copper steamer tape, against a semi conductive outer layer of the cores... But there are i know, many different cable make-up arrangements out there...

 

[Bobster]

I'll only be in charge of proving dead and making it safe for the jointing team to come in. I will try and get photos.

There are 4 identical joints right along side one another (can just see the edges of two of them in the photo).

The reason I think the thumper wasn't as accurate as normal was the fact 2phases were hard down to earth, so it wasn't producing much of an audible arc. The fact there was 8 foot of soil above the concrete protection flags probably didn't do much to help.

 

[SPARTYKUS]

Great thread, would love to see more piccys too!