Channeling cable into blockwork- conduit required?

[foodie]

Having some building work done was talking about where wiring is going etc.As my dad was a sparks (now retired), I fully expected for it to be done how my dad would have done it- wires into pvc conduit and then ready to plaster over

However, the builder says that's now unnecessary and that once the cables into the channel, they are fixed and then it's just plastered over.

I'm not sure whether times have changed or the sparks will just be doing it because it's cheaper/ easier?

Collective thoughts from others would be appreciated.

Thanks,

[Djtemeka]

As far as I'm aware it needs to be metal cover over the cable to stop drilling into it. Plastic conduit won't stop the drill bit

[hairyben]

Djtemeka said:

As far as I'm aware it needs to be metal cover over the cable to stop drilling into it. Plastic conduit won't stop the drill bit

Even metal capping wont stop a drill unless you're quick.

Technically its permissable to bury cables direct in plaster but some form of containment is generally considered better practice.

[CrutyRammers]

Djtemeka said:

As far as I'm aware it needs to be metal cover over the cable to stop drilling into it. Plastic conduit won't stop the drill bit

Neither will metal....guess how I know.

[Belle427]

This is generally what is used, its often forgotton about because it can be a nightmare to fix properly in some walls and takes longer to install.
I think its only designed as protection from plastering trowels and the making good of the wall.

[48k]

We're doing a renovation project and all cabling is either in conduit or covered with capping. Protects the cables from plastering and allows us to pull cables through afterwards too if needed.

[brrapp]

48k said:

allows us to pull cables through afterwards too if needed.

This. Even if you're ignoring the safety aspects, surely it makes sense to future proof it in case you need to rewire or change things at a later date. In a few years time you decide you need to make changes, if the cable isn't in a void or in conduit, you'll be destroying decor and having to raggle and replaster all over again.

[Andehh]

brrapp said:

This. Even if you're ignoring the safety aspects, surely it makes sense to future proof it in case you need to rewire or change things at a later date. In a few years time you decide you need to make changes, if the cable isn't in a void or in conduit, you'll be destroying decor and having to raggle and replaster all over again.

If our new build is anything to go off, the cable is installed in a plastic half conduit that is so tight to the blockwork the cable is clamped.

Power you are unlikely to ever need to pull out & just install more then is required data/other cables. Might be over thinking it OP?

[Muncher]

My uncle runs an electrical contracting business and I just asked him the exact same question about cables in my garage which will be rendered over.

He said they can be covered but in practice it adds cost, provides little protection and in most cases the plasterers don't like it as the plaster doesn't bond to it very well so they often get asked to remove it anyway. He has said just tack it to the wall with clips and that will be fine.

[Ganglandboss]

There is no requirement for any sort of capping or conduit for cables run in prescribed zones (straight horizontal or vertical runs from a wiring accessory, or within 150mm of the top of a wall, or a corner where two walls meet).

I have heard all sorts of reasons for running capping, including 'it protects the cable from lime in the plaster' and 'it protects the cable from nails'. Both of these are b*ll*cks. The normal method of fixing capping to the wall is by using nails, so it will provide bugger all protection against one.

The main benefit of capping is it protects the cable from damage by the mud-slinger's trowel. It may also help if you want to pull in more cables in the future, but proper round or oval conduit is better for that.

Personally, as a qualified spark, I have always run capping if somebody else is plastering, but I am more than happy not to bother if I am making good the plaster.

[Alucidnation]

Ganglandboss said:

I have heard all sorts of reasons for running capping, including 'it protects the cable from lime in the plaster'.....

So, why is this particular reason 'boIIocks'?

[CoolHands]

Presumably because lime does not cause deterioration in pvc sheathing.

[Ganglandboss]

CoolHands said:

Presumably because lime does not cause deterioration in pvc sheathing.

Correct. I'm not even sure gypsum plaster has any lime in it anyway, but whatever its specific contents, plaster does not degrade PVC.

[jas xjr]

Ganglandboss said:

Correct. I'm not even sure gypsum plaster has any lime in it anyway, but whatever its specific contents, plaster does not degrade PVC.

but trowels can cause some damage

[Ganglandboss]

jas xjr said:

Ganglandboss said:

Correct. I'm not even sure gypsum plaster has any lime in it anyway, but whatever its specific contents, plaster does not degrade PVC.

but trowels can cause some damage

That's what I said.

[hairyben]

Ganglandboss said:

Correct. I'm not even sure gypsum plaster has any lime in it anyway, but whatever its specific contents, plaster does not degrade PVC.

Perhaps lime was more relevant to rubber cables? Some of the modern solvent etc adhesives used in building are probably best kept away from cables though...

[Alucidnation]

CoolHands said:

Presumably because lime does not cause deterioration in pvc sheathing.

Correct, however in 'days of old' a lot of houses where rendered and the render sometimes had lime but then had finish coat plaster, and it is the render coat that can dry out pvc.

[hyphen]

jas xjr said:

but trowels can cause some damage

The plasterer would need to be pretty useless to damage a cable plastering, more so if a bonding coat has been stuck over it initially as is often the case,

OP- I think it is the right thing to do from a customer point of view, but adds more time/hassle and increases the quote price so many sparkys try to avoid it I guess, plus in the future its more money for them to have to re-chase a cable then simply pull it though a conduit too.

[Alucidnation]

hyphen said:

The plasterer would need to be pretty useless to damage a cable plastering, more so if a bonding coat has been stuck over it initially as is often the case,

OP- I think it is the right thing to do from a customer point of view, but adds more time/hassle and increases the quote price so many sparkys try to avoid it I guess, plus in the future its more money for them to have to re-chase a cable then simply pull it though a conduit too.

And how do you think bonding is applied?

TBH, all of what you have typed there is complete st.

[227bhp]

You have zero chance of pulling a cable through a nailed/screwed on cable cover. The ones that allow you to do that are tubular conduit.

It is a bit of a waste of time really, I can see no advantage at all, it just looks a bit better before it's covered over.