Terminate SWA armour outside and take just internal wires into house/CU?

[sparkwright]

It's interesting how the bedding on SWA can vary.

Some is crumbly.
Some is like cable sheath.
And some is really, really tough.

One would like to think if the bedding was tough, then it could be considered to be the equivalent of a normal sheath, but common sense doesn't come into it.

I suppose larger SWA has tougher bedding, perhaps.

Haven't seen that clear sellophane type stuff in SWA for a long time. Anyone know why?

 

[ban-all-sheds]

My other question to the OP would be how has the 6mm conductor size been arrived at?

My guess is not by any method which would have credibility wrt an EIC.

 

[JohnW2]

I'm not so sure. A directly buried SWA might develop a fault, especially if the outer sheathing is damaged on installation.

Nothing is impossible, but I would think that extremely unlikely. Even if, after a few decades, armour exposed during installation (that, in itself, unlikely) 'corroded away', there's no particular reason why a 'fault' should develop in the cores. Of course, particularly if it hadn't been buried deep enough, there is always the risk of damage by humans (spades and pick axes!!). However, I would personally be happy to live with that extremely small risk. Indeed, if the worst came to the very worst, it would only take a few minutes to disconnect the cable at the CU (or an intermediate JB, if one were present).

My other question to the OP would be how has the 6mm conductor size been arrived at?

Yes, I nearly asked that myself. However, it sounds 'more than enough' (particularly if one assumes that he intends to continue feeding it from a 32A MCB) and I have nothing against 'future proofing', particularly when one is talking about buried cables!

Kind Regards, John

 

[JohnW2]

It's interesting how the bedding on SWA can vary. ... Some is crumbly ... Some is like cable sheath. .... And some is really, really tough. ... One would like to think if the bedding was tough, then it could be considered to be the equivalent of a normal sheath, but common sense doesn't come into it.

Indeed but, as you imply, the problem is the variability. It would probably not be very satisfactory if users (be they electricians, DIYers or whoever) had to make case-by-case individual judgements as to whether the bedding of a particular bit of SWA was, or was not, adequate to be regarded as 'sheathing'.

Kind Regards, John

 

[333rocky333]

Thanks flameport, I will replace that MCB,

There no longer generally sold, you can order from MEM but takes time and a lot of money

 

[JohnD]

you would find some on the used market. Fleabay will have some. Easier if compatible (as with some Memera CUs you can fit Memshield components) as it is much more common brand in commercial and industrial installations than in houses.

Are they the same as these?
http://www.ebay.co.uk/itm/MEM-QEB-TYPE-1-M6-5-10-16-20-32-40-45-AMP-BS3871-MCB-TRIP-EATON-CIRCUIT-BREAKER/281478589553?_trksid=p2047675.c100005.m1851&_trkparms=aid=222007&algo=SIC.MBE&ao=2&asc=40760&meid=ca47d0dd23034ce59e2d59c0cc01a82a&pid=100005&rk=2&rkt=6&sd=201768378207

I see they are marked M6

 

[Iggifer]

Are they the same as these?

Yea they're the same. Have the same breakers in my flat, they're reasonably common around here.

If there's a board with 3871's in it, it's either Wylex, MK or MEM round here. Very rarely see Crabtree (at all really), Square D, Proteus, GET/Vynicker, Volex. Don't know if that's a regional thing or just how it was.

We have a lot of Eaton/MEM installed round these parts generally as it's on the council spec

 

[john4703]

I was thinking about the original question. The ideal would be to run the SWA to the consumer unit. SWA hidden behind plasterboard in a safe zone is fine. The problem is the two bends one outside and one inside the building.
I was thinking that if the original poster had a very long drill bit and skill he could drill a hole starting say 1500mm from the floor inside and angle it so it emerges 100mm above the ground outside. I've done holes like that using a short drill bit and loads of screwed on extensions. It gets hard and slow but can be done and the advantage is the the bends in the swa are slight so do not take it far from the wall surface. I admit is is hard to do, if I was doing it I'd start with a 10mm pilot hole then increase it to 18mm. The hardest part is getting started but after the first couple of hundred mm it keeps on track.

 

[JohnW2]

I was thinking about the original question. The ideal would be to run the SWA to the consumer unit. .... The problem is the two bends one outside and one inside the building.

I agree, on both points.

SWA hidden behind plasterboard in a safe zone is fine.

If it's SWA, it doesn't even have to be in a safe zone (although it probably would be, anyway)! Getting the SWA behind don-n-dab plasterboard (without too much destruction) could be the main difficulty.

Kind Regards, John

 

[RF Lighting]

I don't think anyone has mentioned so far that if the swa is run all the way to the CU then the cable will not require RCD protection which is the best design.

 

[deadshort]

The supply has an RCD main switch already fitted.

Regards,

DS

 

[JohnW2]

I don't think anyone has mentioned so far that if the swa is run all the way to the CU then the cable will not require RCD protection which is the best design.

True - but without some non-trivial surgery, I don't think that CU could provide a non-RCD-protected way.

Kind Regards, John

 

[Iggifer]

True - but without some non-trivial surgery, I don't think that CU could provide a non-RCD-protected way.

Kind Regards, John

Switchfuse in the (presumably) external meter cabinet. Job done. No RCD, no internal SWA. Everyone's a winner

 

[333rocky333]

Haven't seen that clear sellophane type stuff in SWA for a long time. Anyone know why?

maybe it smoked or gave off fumes, I quess the makers have never ending regs nowadays

 

[Iggifer]

I had some 25mm 4 core last year from a leading national wholesaler that had cellophane in it.

Perhaps it's just manufacturer specific?