Concealing cable bundle

[mikeey84]

Hi All, I'm converting an old kitchen into a downstairs loo, and upon removing the old cabinets, I've discovered that the wiring for the extension (lighting, socket ring, garage radial, cooker radial, I think) have been run surface mounted behind the units (cable tied as a bundle).

On one wall I'm planning a concealed cistern toilet, so can have them surface mounted there and hidden by the unit.

However they run for about 45cm along the side wall, and I've not got a huge amount of depth to play with, so a cabinet is a no go.

Any ideas what I could do, short of a full reroute of the cables?

I thought maybe a blanking plate, but they dont run straight, and I'm not sure on the visual aspect.

Other thought was some sort of capping, but not sure what spec is needed.

Any ideas?

 

[sparkwright]

Some questions first.

Do the wires run under the tiles to the left - or do they go through the wall?

Is there a consumer unit or fuse box very near?

 

[mikeey84]

Some questions first.

Do the wires run under the tiles to the left - or do they go through the wall?

Is there a consumer unit or fuse box very near?

I think they go through the wall, as they appear too, and that is where the extension starts, as in the new wall runs perpendicular to that point.

The consumer unit is about 2.5m to the right

All circuits are RCD protected, and we had a new CU installed about 3 years ago

 

[sparkwright]

Without making a massive job out of this, you could consider fitting an EARTHED metal plate (3mm minimum thickness I THINK) over the cables.

The problem is HOW do you earth this.

Running a 4mm2 earth cable from the consumer unit to this plate would be best, or only, way to earth it.

Bit of bodge, no substitute for re-routing and re-wiring, but what do you do?

 

[mikeey84]

The incoming water main, which is metal, and earthed/bonded back to the CU is about 30cm away. Could I connect to that?

Edit- my head is saying reroute, but that seems like a huge effort for 40cm of wire. I'd probably split a 40mm waste pipe and use that as surface trunking instead, and artfully decorate it!

 

[sparkwright]

Common sense would suggest just connect it to water main BONDING, however this is EARTHING. But it all gets connected to the same point. Let's see what the others think.

Another quick fix, though again not ideal, would be to fit a large inspection panel in the wall which would reveal the cables when opened. Again, subject to controversy, as the panel won't be an electrical accessory as such - but you have to use a bit of common sense in these situations.

 

[mikeey84]

Common sense would suggest just connect it to water main BONDING, however this is EARTHING. But it all gets connected to the same point. Let's see what the others think

I knew I would get it wrong, hence the use of both terms in my post

 

[EFLImpudence]

Without making a massive job out of this, you could consider fitting an EARTHED metal plate (3mm minimum thickness I THINK) over the cables.

Such a plate doesn't have to be earthed.

 

[mikeey84]

Such a plate doesn't have to be earthed.

Is that because the RCD means it's not needed?

 

[sparkwright]

Such a plate doesn't have to be earthed.

I assumed it would be, bearing in mind cables not in safe zones are required to be in earthed metal conduit, earthed micc and the like. Unearthed metal capping out of safe zones is never acceptable, even though it is paper thin.

 

[EFLImpudence]

522.6.204(iv)

 

[EFLImpudence]

522.6.202 A cable installed in a wall or partition at a depth of less than 50 mm from a surface of the wall or
partition shall:
(i)...
or
(ii) comply with Regulation 522.6.204.

522.6.204 For the purposes of Regulation 522.6.201(ii), Regulation 522.6.202(ii) and Regulation 522.6.203(ii),
a cable shall:
(i) ...
or
(ii)...
or
(iii)...
or
(iv) be provided with mechanical protection against damage sufficient to prevent penetration of the cable by
nails, screws and the like, or

 

[JohnW2]

Such a plate doesn't have to be earthed.

I assumed it would be, bearing in mind cables not in safe zones are required to be in earthed metal conduit, earthed micc and the like. Unearthed metal capping out of safe zones is never acceptable, even though it is paper thin.

522.6.202 A cable installed in a wall or partition at a depth of less than 50 mm from a surface of the wall or .... (ii) comply with Regulation 522.6.204. ... 522.6.204 .... (iv) be provided with mechanical protection against damage sufficient to prevent penetration of the cable by nails, screws and the like, or

Quite so - but, quite apart from regulations, just common sense....

... if the metal plate provides adequate mechanical protection to the cable, then it does so whether it is earthed or not - and it would be silly to suggest that anything metal which does, or may, come into contact with (the outer sheath of) cables has to be earthed!

Having said that, the regs do talk about "earthed metal conduit" as one of the options for buried cables but, unless they are thinking about conduit which is not thick/strong enough to satisfy 522.6.204 (iv) as regards 'adequate mechanical protection', this might be another example of the regs not necessarily being intended to make sense

Kind Regards, John

 

[mikeey84]

OK, so consensus seems to be that a metal covering, as long as it provides "adequate" mechanical protection seems like a reasonable, if imperfect, solution.

Now, I'm guessing that this is a can of worms, but is there an acknowledged definition of "adequate"?

Are we talking steel, and 1mm? 2mm? 3mm?

 

[JohnW2]

OK, so consensus seems to be that a metal covering, as long as it provides "adequate" mechanical protection seems like a reasonable, if imperfect, solution. ... Now, I'm guessing that this is a can of worms, but is there an acknowledged definition of "adequate"? .... Are we talking steel, and 1mm? 2mm? 3mm?

Yes, steel (or similar) and the thickness is as much down to common sense as anything else - as you know, the reg says, the idea is simply for it to be "sufficient to prevent penetration of the cable by nails, screws and the like".

I don't think there is any explicit definition of 'adequate' in the Wiring Regs (BS7671) but, like Sparkright, I seem to recall having seen a 'guideline' of 3mm somewhere (maybe in the 'On Site Guide') - and no-one other than a complete idiot would persist in trying to get a drill, screw or nail through 3mm of steel until they succeeded!

Kind Regards, John