Blagdon Powersafe kit connection problem Ask questions and find answers to many subjects relating to electrics and electrical work

[daveace]

Hi folks,

I have the Blagdon Powersafe 20m kit (Google "blagdonthepondmasters.co.uk/objects/pdf/Power_Leaflet.pdf") installed in my garden but recently I noticed the RCD was tripping, and I have discovered rain is getting into the connection between the regular 3 core flex and the armoured cable causing a short. If you are unfamiliar with the product all connections are fixed in order to maintain their IP rating and comply with regs, and before you ask, everything is installed in accordance with the manufacturers recommendations and the connections are as tight as possible.

Although out of warranty, the manufacturer has offered to send another kit, but this means digging up half of my garden, which I am obviously trying to avoid.

The question is this - can I connect an armoured cable to a standard 3 core flex thereby replacing the leaking connector?? Would an IP68 connector (http://www.awin1.com/awclick.php?mid=1228&id=61071&p=http://www.screwfix.com/p/ip68-cable-connector/47675) housed inside an IP66 enclosure (http://www.awin1.com/awclick.php?mid=1228&id=61071&p=http://www.screwfix.com/p/ip66-enclosure-125mm/50115) be OK or is it simply not possible to connect an armoured cable to a 3 core cable?

At the moment the leaky connector is wrapped in plastic which is doing a temporary (but very ugly) job, but I'd rather leave it like that than cut the cable only to find I cannot reconnect them.

Thank you in advance for any constructive help you can offer.

[collectors]

Use a connection box that a swa glad can be used with using the earth washer with tag to enable earthing of the steel wire on the swa cable. Dont use one of the tubular connectors as you will loose earth continuity on the steel wire of the armoured cable.

[ericmark]

I think to comply with Part P you have to follow manufactures instructions when fitting a pre-assembled unit.

If Part P is not an issue then experience has shown me near impossible to stop water getting in a joint which with the suns warmth and with air inside is forever trying to suck or blow out air.

The only way is to fill the space with a solid or liquid and not air.

There are many methods used the most common is called potting. This means some two part mix is poured in and then becomes solid. There are two basic types the standard non re-enter-able and the stuff which sets like a jelly and you can with some work dig it out again.

Often I have was Vaseline jelly and warmed it before filling the void. Don't use grease it is slightly corrosive and some type may not insulate as expected.

Keep joint boxes out of the sun and if possible out of water. Vaseline jelly not only helps keep water out but also ensures any screw fittings don't bind as they are tightened.

Buried cable joints need to be epoxy resin filled. Using resin lined shrink sleeve will also work. Silicon sealant will often do the job but it has to be right type. The type cured with moisture is best. However unless you deal with RS Components getting correct sealant from DIY shed is near impossible.

There is no one way but a whole host to do same thing. However I buy from an electrical whole sale outlet. Some items can surprise one. For example Wellingtons do not insulate. They have graphite in the rubber mix to stop static build up. Hence warning about grease. Vaseline jelly has been used for years however I have had some funny looks for keeping a stock because of it's other use!!!!

[daveace]

Use a connection box that a swa glad can be used with using the earth washer with tag to enable earthing of the steel wire on the swa cable. Dont use one of the tubular connectors as you will loose earth continuity on the steel wire of the armoured cable.

OK, that's great! I understand how to cut the swa cable and fit the gland, but how do I earth the tag? I understand how it works if I were terminating it at a consumer unit but I can't figure it out when it is outside.

[ericmark]

In a splice kit you will have a split collar which goes under the steel wire armour to stop the armour digging into the cable inside it. When working at the end of a cable it does not need to be split. So you find some tube that will fit over the inner sheave and then with a jubilee clip fasten a earth cable to the steel wire armour. You must have inner tube to stop crushing the SWA into the inner cable. The whole thing then goes into either epoxy resin.
An example here Google "screwfix.com/p/prysmian-puj10cc-resin-joint-10mm-4-core-max/43363" in screwfix catalogue. Although this example is too big for what you want.
One method I have used in the past is a conduit box like this Google "screwfix.com/p/20mm-2-way-galvanised-conduit-box/46004" with a gland Google "screwfix.com/p/external-gland-kit-20s-ip66-pack-of-2/25996" and a stuffing gland Google "screwfix.com/p/male-comp-gland-black-20mm-pack-of-2/80851" with crimp connectors one 3mm brass screw for earth and fill with potting compound. Not really the best as the steel box threads can corrode and lose the earth however so can the SWA so I would use a smear of wax (As had that at hand for cutting threads on conduit) on the threads.
Again you can fill the box with anything water proof and even melting candle wax into the void will stop water ingress. Really case of using common sense.

[collectors]

The swa gland is supplied with a brass washer that has a protrusion sticking out with a nut & bolt hole, this is the earth tag. So even if you are using one of the swa cores as an earth, still put a link from the earth terminal to this tag.
If you was using a metal box it would be normal to dill the box in line with this washers bolt hole & bolt through the box & washer. But in your case, bend this part of the washer up & connect to the washer inside the box with a short bit of cable to your earth connector. .

[daveace]

Thanks everyone - that was a great help!