Can't connect the SWA cable. Practical help please.

[Onoff]

There was some b@llocks from memory with the NICEIC wanting to "de-neutralise" the earth. 

Edited Thursday at 23:01 by Onoff

[Nickfromwales]

1 minute ago, Onoff said:

There was some b@llocks from memory with the NICEIC wanting to "de-neutralise" the earth. 

Star generation put paid to that anyways lol. N/E....Tomayto/tomato.

[andyscotland]

9 hours ago, joth said:

Funny enough the last electrician that worked on my CU (in 2024) complained it must have been installed (in 2021) by someone old school as black was sleeved as blue, and the modern convention is to eschew black as neutral. I just smiled and nodded (perhaps with a shut up and do what you're here to do vibe)

 

Interesting... I wonder when that changed. Certainly after I trained (which was a while ago, though well after the new colours were introduced).

 

Very helpful to know though!

[saveasteading]

8 hours ago, Nickfromwales said:

not one of them will pick up all the cable clippings etc after them

On a site they will claim the slab is dirty and its not their job to clean the floor.

If the floor is clean.... they were going to do it later... but progress is the priority.

terrible.

 

So have I picked up my clippings which are on earth or tarmac?  Some.  I'll have a word with myself later.

 

I bought a box af SF. It reads as if it is unbranded but it's the same as the existing one.... pop outs not grommets.

Also lever connectors. 

No excuses left...but what if I can't see any stray wire causing a short?

[ProDave]

26 minutes ago, saveasteading said:

No excuses left...but what if I can't see any stray wire causing a short?

MCB or RCD tripping.  If RCD you need some test gear like an insulation tester.

[Kelvin]

21 hours ago, Nickfromwales said:

Bigger box helps, as it’s just punishing to struggle with a smaller box with everything in such close proximity. Also gives you the option to add to it later without losing too much more hair. 

If I’ve learnt anything building a house it’s that it’s usually best to fit something slightly bigger than you actually need if you have flexibility with sizing things. Anything I’ve done where the size is just right has ended up making the job harder. 

[Kelvin]

23 hours ago, saveasteading said:

Nice idea. But that was the easiest bit.

A really sharp knife helped too....must check I didn't do damage with it.

 

For connections inside the boxes I've used old-fashioned screwed terminal strips. 

Would modern lever connectors be better? I see some at screwfix are a fraction of the cost of the bigger name wago. I like the idea of getting second shots at it too, ie the lever releases.  The wago's I used once were push-in and perhaps fixed.

 

I'm thinking I will buy a better and bigger box today, and lever connectors.

 

The push in Wagos can be re-used. Twist the cable from side to side while pulling. 
 

[saveasteading]

1 hour ago, ProDave said:

insulation tester.

Could it be that the old cable has failed in flexing it? It has been there for the over 30 years I've lived here.

I was going to change it later but perhaps should do it now.

[Nickfromwales]

20 minutes ago, saveasteading said:

Could it be that the old cable has failed in flexing it? It has been there for the over 30 years I've lived here.

I was going to change it later but perhaps should do it now.

How many cores is the SWA? 

[saveasteading]

3 cores 

[TerryE]

BTW I personally always use crimp terminals on multi-core cables going into screwed connectors, especially if the cable is carrying a sustained high current load. However, these aren't needed for Wago type connectors as the connector maintains good contact if the multi-core deforms under clamping load.

[saveasteading]

This is the old cable, coming from the attic, then was into the conduit bottom left.

 

It did feel a bit stiff as I bent it around, but attributed that to many layers of gloss paint.

 

BTW I am aware that the wall needs painting and the corner needs a new block.

The sun is doing a good job in exposing an ancient layer that was painted over dirt, well over 30 years ago i think, so I'm letting it. The cladding was about 1930 and still has a resinous smell when cut. 

It's been overpainted thrice in my time here. The first by professionals who i think only prepped when being watched.. some failed in a few years. The second time by 3  steel cladders waiting for the next job... lasted well. Third by me in lockdown... and that has stayed put too.

 

I'd like to make the corner with 2 splays out of one block of wood, rather than rectangular with 2 wedges added. But it would be a big lump of wood  and I'm not sure I have the skill. Hence years of not getting round to it.

[dpmiller]

is that T&E? I'd be replacing that...

[saveasteading]

10 hours ago, dpmiller said:

that T&E? I'd be replacing that..

I am. I thought I'd do it in stages. 

 

For my education, why is T & E wrong in principle?

[Onoff]

58 minutes ago, saveasteading said:

I am. I thought I'd do it in stages. 

 

For my education, why is T & E wrong in principle?

 

UV from sunlight degrades the sheath is the main thing. You could run a line of conduit and put it in that. 

[saveasteading]

Yes I've even got the conduit ready.

 

The existing cable ran underground for 25m then up a pole to a 500W. That must have been pushing its capacity. floodlight. I changed that to 30W.

 

It now supplies an electric gate which is quite low power.

 

I'm thinking an outside socket would be a sensible addition for gardening but perhaps also car charging..... slow only.

 

So I'm thinking the cable should be bigger than smaller. 2.5mm T&E ?

 

[andyscotland]

1 hour ago, saveasteading said:

I'm thinking an outside socket would be a sensible addition for gardening but perhaps also car charging..... slow only.

 

So I'm thinking the cable should be bigger than smaller. 2.5mm T&E ?

 

The cable sizing partly depends on where/how the circuit is supplied from and the sizing of the protective device. Is this direct from the consumer unit or a fused/unfused spur from something else?

 

I assume the circuit already has RCD protection (wasn't always provided for exterior lights in the old days but definitely required for a socket).

[Nickfromwales]

41 minutes ago, andyscotland said:

 

The cable sizing partly depends on where/how the circuit is supplied from and the sizing of the protective device. Is this direct from the consumer unit or a fused/unfused spur from something else?

 

I assume the circuit already has RCD protection (wasn't always provided for exterior lights in the old days but definitely required for a socket).

One get out of jail option here is to leave it on an MCB, and fit an RCD socket. If the ‘dodgy’ cable is to be left on for any amount of time.

 

Link

 

Sounds like this is a split load board from previous comments? If so, and it’s “high integrity” you can put an MCB before the RCD, same thing if it’s a dual RCD CU. No more nuisance tripping then. 

[saveasteading]

3 hours ago, andyscotland said:

the circuit already has RCD protection

The circuit/ fuseboard/ RCD etc were all replaced professionally when we moved in. However this cable is  off an existing internal circuit.

When the old cable that I  am replacing used to cause cuts in wet weather, presumably a fault underground  it could trip at any one of three trips.

This tripped at the RCD which carries the whole house circuitry.

I could take pics if that helps, and avoids me using the wrong terminology.

 

3 hours ago, Nickfromwales said:

If the ‘dodgy’ cable is to be left on for any amount of time.

 

That is not the plan.  If I can get this to work as is, then I will proceed and change the old cable within 2 weeks. New cable in trunking , up into the dry and spacious attic and do a new box connection there. The existing cable I assume to be sound where it is indoors.

I am now thinking that @ProDave 's point of the old cable shorting, and likely to be caused by the bend I've put on it (it was all working except in very wet weather).   So for now perhaps to  just replace a couple of feet with new bendy cable, and keep the old one straight.

 

I should say that I did ask a couple of electricians to do this, but they have been 'too busy' for 6 months now. 

For obvious reasons they'd rather do new, clean work than this sort of thing.

All decent small contractors are fully booked and turning work down in the SE. Any that are available will likely be as good as me but less interested.

[andyscotland]

5 hours ago, saveasteading said:

 However this cable is  off an existing internal circuit.

 

Is the internal circuit a ring main, or something else?

 

Is there a fused spur unit where it connects to the internal circuit, or is it just connected to the back of a socket / a junction box etc?

 

If it's connected direct (e.g. it is an "unfused spur") then it should be wired in the same size cable as the rest of the circuit (likely 2.5mm²) but it can only serve a single point (single socket/double socket/light).

[saveasteading]

For interest.

I've found this connection box in my stores. It seems to be very classy with 3 screw-in sleeves with integral and tightening seals. The box back is completely in one piece of moulding, and the holes are made by tightening in the sleeves, whence the knockouts break off.

Also a connector block.

 

It is made by els Spelsberg, and also labelled Attema. New names to me but the build quality (and attention to detail) is astounding.

 

There are also 2 sealing grommets stuck to the front plate, presumably to seal the screw holes.

I cannot figure out what the rubber strip joining these grommets and extending to the rim seal is for?

 

PS. Ive found it is available at SF for £8.99. But it is described as "unbranded". 

Edited Sunday at 15:16 by saveasteading
PS

[Nickfromwales]

55 minutes ago, saveasteading said:

I cannot figure out what the rubber strip joining these grommets and extending to the rim seal is for?

Sacrificial, as it's part of the manufacturing process where the material is injected.

[Nickfromwales]

57 minutes ago, saveasteading said:

It seems to be very classy with 3 screw-in sleeves with integral and tightening seals

AKA cable entry / stuffing glands. I use these exact same boxes on outdoorsy stuff, and like the fact the lids are click on / off.

 

I always set the box in place, drill the fixings holes, and then remove. Then I apply a bit of CT1 to the holes and put the box back in place so the screws go through wet CT1  for belt & braces; even more so if the box is subject to driving rain.  Apply just enough so that it gets displaced and comes through the fixing holes.

 

You'll notice the 4 square tabs that are visible at the centre of each side. Ironically, these are drain holes, and you should punch out whichever one is the lowest point of the box, when mounted. This allows any water or moisture to escape in the event of some getting in there, howsoever. Basically so the box cannot slowly fill with water /moisture over time.

 

I also seal 3 sides around with the same clear CT1, but never do the bottom edge, for the same reason so that any water that gets behind can run down and out.

[SteamyTea]

On 26/07/2025 at 09:31, saveasteading said:

now supplies an electric gate which is quite low power

May have a high start up load. Induction loads are pain.

[Nickfromwales]

1 hour ago, SteamyTea said:

May have a high start up load. Induction loads are pain.

These are usually geared down to hell, so next to nothing for start up loads/shunt resistance. Was DC on the last few I installed (SELV).