Cable protection

[Richard C]

Rather than use plastic sheathing/capping, I’ve been using steel capping on all the wiring to existing sockets/light boxes (most of the plaster has had to come off!) & any new ones that have been added, including any cables run in the safe zones.

I’ve bee doing this on the assumption that it would improve safety as a masonry bit will go through plastic but not steel. After re-reading the regs, I’ve now had a horrible thought that perhaps I should have bonded the steel capping to the earth terminal in the box! Is this required or does steel capping qualify a mechanical protection not needing an earth bond.

 

[joe-90]

There's a thread just down the page a bit called 'capping'.

You should find it useful.

//www.diynot.com/forums/viewtopic.php?t=72404

 

[RMS]

metal capping does not require bonding.

Although it will provide better protection than plastic it will not stop and masonry bit drilling through it. ie. safe zones.

 

[joe-90]

I disagree RMS. I can easily tell by feel if I hit some capping then I shine a torch down the hole and look for shiney bits or a small insulated screwdriver will feel smooth rather than rough. Then again I use a battery drill without the hammer.

 

[RMS]

lol,

can you be sure that all DIY'ers would carry out your procedure?

 

[joe-90]

I guess not, but I'm sure you recognise it like I do.

 

[RMS]

Think most sparks have been there.

 

[Richard C]

RMS; thanks for that, I was beginning to think I had severely dropped off but you’ve set my mind at rest. I do, however, agree with joe-90; it’s almost impossible to drill through steel with a standard masonry bit even on hammer as it just doesn’t have the correct cutting angles (trust me I’m an engineer!), this is why I’ve been using it, although I can appreciate that a true muppet could persevere to the extent that they could probably grind/bend their way through almost anything!

I’m obviously not a spark but I do have electrical training & some commercial inspection/testing experience as part of my background so I don’t really understand why steel capping is not mandatory (very little difference in cost) as it would be of far more benefit than some of the seemingly, fathomless (to me anyway) other regulations in force!

 

[TopTrumper]

RMS; thanks for that, I was beginning to think I had severely dropped off but you’ve set my mind at rest. I do, however, agree with joe-90; it’s almost impossible to drill through steel with a standard masonry bit even on hammer as it just doesn’t have the correct cutting angles (trust me I’m an engineer!), this is why I’ve been using it, although I can appreciate that a true muppet could persevere to the extent that they could probably grind/bend their way through almost anything!

I’m obviously not a spark but I do have electrical training & some commercial inspection/testing experience as part of my background so I don’t really understand why steel capping is not mandatory (very little difference in cost) as it would be of far more benefit than some of the seemingly, fathomless (to me anyway) other regulations in force!

Richard, you might have a good theory on capping, but practical protection? i think not.

 

[RF Lighting]

it’s almost impossible to drill through steel with a standard masonry bit even on hammer as it just doesn’t have the correct cutting angles (trust me I’m an engineer!)

Try it, and you may just be suprised at how easy it is to drill through.

In my experience it is easier to drill through steel capping than some brick / stonework.

When fixing steel capping it is common to drill stright through the lip of the capping and into the brick with a standard masonry bit.

 

[Qedelec]

The only purpose of capping, whether plastic or metal is to protect the cables from the plasterers trowel.
if you are concerned about protection, conduit is the best route.

There is cable available with a thin earth sheath which would also afford shock protection.

 

[jj4091]

RMS; thanks for that, I was beginning to think I had severely dropped off but you’ve set my mind at rest. I do, however, agree with joe-90; it’s almost impossible to drill through steel with a standard masonry bit even on hammer as it just doesn’t have the correct cutting angles (trust me I’m an engineer!), this is why I’ve been using it, although I can appreciate that a true muppet could persevere to the extent that they could probably grind/bend their way through almost anything!

I’m obviously not a spark but I do have electrical training & some commercial inspection/testing experience as part of my background so I don’t really understand why steel capping is not mandatory (very little difference in cost) as it would be of far more benefit than some of the seemingly, fathomless (to me anyway) other regulations in force!

Richard, you might have a good theory on capping, but practical protection? i think not.

And very little difference in cost, I think not

 

[Richard C]

Try it, and you may just be suprised at how easy it is to drill through.

I have hit a steel cable cap with a standard masonry bit, rather stupidly one I had previously put in feeding an under worktop fridge S/O! You definitely know you’ve hit it which should tell you something ain’t right. It won’t protect against nail guns & the like & if determined you will eventually grind & bend their way through it but it’s certainly more robust than plastic & if I'd used that, I would have had to rip the whole lot out again to replace the cable!

With regard to the extra cost, I’m buying Galvanised steel capping for less than £1 per 2m length; it’s about 2x the cost of plastic but the extra this will add to a rewire will probably be less than £30 for a 3 bed house; nothing when compared to the cost of the cable, fittings & labour!