A good while back I had some cable laid under the patio into the garden for future use - most probably pond pump and garden lighting.

The sparkie taped up the end of the cable out there where the wind blows and the rain falls.

I'm getting twitchy - especially as I periodically suffer from a power mains ring gremlin causing the central trip switch to go - tho' no individual power circuit's switch (RCB?) trips and the house lighting remains unaffected.

Yep I've had the system checked twice now by competent sparkies and tho there were a couple of issues sorted, the phantom tripping continues.

What device should I get to terminate the 12mm cable rather than rely on the sparkie's red tape?

Yours thankfully, Green Fingers

PS Liked the jokes!  

Thanks for the quick response. Cable isn't on a specially/new dedicated RCB. Its linked (a spur probably)into one of the (5) power main rings/circuits in the house - each of which has its own trip. (It does have its own wall switch inside the conservatory)

12mm i assume as overall diameter.

No need for specific RCD for outdoor kit, it can share one with your ring mains if is a split load board used.  (although it is better on its own).

Even if it had its own MCB, and this was off, then the N would still be connected, and the RCD could still trip.

Best to disconnect, not terminate the end.

If you want to terminate it, i would use a 'pot end', which is basically a resin joint with only one entry(or the second entry closed off).  Cut all armours off, cut each conductor to a diferent length, and fill the joint.

Very surpised he livened it up at all

BTW, TT systems are predominantly overhead, but can also be from undergorund networks.

As Lec is implying one cannot really generalize Handy.

For example you can have overhead cables and have a PME (Protective Multiple Earth) which makes what many would think as a TT arrangement (overhead cables) is actually TN-C-S (Terra-Neutral-Common-Split).

Lec: agreed but I have a habit of automatically fitting RCD's to outside circuits like I breath automatically. God knows why coz as ya say if the CU has an RCD 30mA then why not. One probable reason I do it is so the client can isolate that ONE circuit as RCD's in CU's tend to be expensive and RCBO's even more expensive.

12mm probably outside dia.

RR

I did not mention number of cables on overhead supply Plug - but agreed 2 and 2 then it has to be TT.

Ray

TN-C-S = terra neutral combined seperate.

meaning N and E combined in supply and seperate in installation

the N combined with the E utilises a PEN or CNE conductor.

In the old school days, all overhead where TT, but as time has gone by, most overheads are PME complient.

Im PME is available, it may not be used in some instances anyway, eg. swimming pools, petrol station forecourts etc

[quote author=Green_Fingers  link=1089393180/0#11 date=1089637355]When the patio was laid the contractors had this 12mm diameter (external) black "heavy rubber" cable laid under the paviours and out into a bed of cobbles. [/quote]

Is it not Steel-wire Armoured (SWA) cable, then?

You shouldn't just bury an unprotected cable.   If it's not SWA, is it in any sort of conduit?    Do you know how deep it is buried?  Do you know if there is warning tape above it?

Sounds like there might be a number of things wrong here....