Alternatives to PVC trunking

[Ric2013]

It is RCD protected. Surely the 50mm is about RCD protection?

If the same zone issue applies, then I make my battens and board 56mm thick at least. But this may be stretching interpretations IMO as then the PVC trunking needs to be in prescribed areas/RCD too?

PS Apologies for LSOH comment. I have looked into it, and some LSF cables are not PVC free, but I think LSOH LSF is.

 

[Ric2013]

To clarify, I meant a batten each side of cable, and a board as a form of capping. NOT the whole wall.

Warning stickers on the board too.

Leaving plenty of space inside the boxing to avoid heating the cables.

 

[JohnW2]

It is RCD protected. Surely the 50mm is about RCD protection?

No. If it's buried less than 50mm below the surface of a wall, it has to have both RCD protection and be run in safe zones. It's obviously a matter of opinion as to whether your board/batten counts as 'a wall' but it does theoretically pose much the same problem, that someone who didn't know the cable was there could screw/nail/drill through it.

If the same zone issue applies, then I make my battens and board 54mm thick at least. But this may be stretching interpretations IMO as then the PVC trunking needs to be in prescribed areas/RCD too?

It (the PVC trunking) would have to be RCD protected and 'in safe zones' if it were buried in a wall. However, it's usually on the surface, hence visible and therefore not posing the issue of a 'cable concealed in a wall'.

Kind Regards, John

 

[Ric2013]

Interesting. I knew about safe zones, but thought they extended all the way through the wall's thickness.

Had hoped the batten and board would not be considered concealed. Covering with perforated hardboard might also get around it? You can see the cable, as someone previously commented.

Would avoid

someone who didn't know the cable was there could screw/nail/drill through it

as it seemed like something strong to fix to...

Yet there is a commercially available pine capping. Looks good on light drops, but too small to fit a 6mm T+E.

I suppose it depends if the batten and board be considered a form of trunking or not. Possibly best to put some hardboard BEHIND the cable too, then it is off the wall surface, just to follow the rules to the letter?

 

[JohnW2]

Interesting. I knew about safe zones, but thought they extended all the way through the wall's thickness.

They essentially do, but that doesn't alter the fact that cables less than 50mm deep have to be in those safe zones (and RCD protected).

Had hoped the batten and board would not be considered concealed.

As I said, that's a matter of opinion, and opinions will presumably vary. I would personally think that if you covered it with 'warning stickers' that would be OK - but others may disagree.

Covering with perforated hardboard might also get around it? You can see the cable, as someone previously commented. Would avoid

someone who didn't know the cable was there could screw/nail/drill through it

as it seemed like something strong to fix to...

Hmmm - I think I'll I'll leave you to argue with Mr Jobsworth about that one Maybe some little perspex/glass 'windows' showing cable would satisfy him!

IYet there is a commercially available pine capping. Looks good on light drops, but too small to fit a 6mm T+E.

I suspect that would have to be in a safe zone and RCD protected. After all, the whole idea is to just look like a piece of wood and 'conceal' the fact that there is a cable below. If it was obviously cable trunking/capping, that would be different, but presumably the whole idea is that it shouldn't look like what it actually is?!

I suppose it depends if the batten and board be considered a form of trunking or not. Possibly best to put some hardboard BEHIND the cable too, then it is off the wall surface, just to follow the rules to the letter?

I don't think that board behind the cable would be needed. In common sense terms, it's all down to how obvious/apparent it is that there is a cable behind it. As I said, I would personally be fairly comfortable if it was very clearly labelled - but others (maybe including 'inspectors') may well have different opinions.

Kind Regards, John

 

[Ric2013]

If it was obviously cable trunking/capping, that would be different, but presumably the whole idea is that it shouldn't look like what it actually is?!

Surprisingly, it looks exactly like the PVC version (even has a clip-in lid), except it is wooden.

I like the glass windows idea. Very quirky!

 

[ekmdgrf]

,

Regulation 522.6.2 states that: in fixed installation where impacts of medium severity can occur protection shall be afforded by: the provision of additional local or general protection against mechanical damage,

Okay, asked the question, that was the reply.

Does this mean batten and board (as I have plenty of it lying about, and a carpenter friend) would do?

I think you have to go back to your inspector with that question. They are the person who has to approve it, so while we can all pass opinion, it's only the inspectors opinion that matters.

The problems are two-fold, the first is that the quoted regulation is very vague. What is an "impact of medium severity"? What is acceptable protection? Particularly bad is the phrase "can occur", since almost anything can occur. I'm sure one could interpret the the above regulation to mean that one should install concrete bollards on the end of your drive to mitigate the risk of a bus coming off the road, hitting your house and damaging the cable. Is that a medium severity impact? It is compared to 10KM meteor hitting your house.

As already stated too, the other problem is that covering the cable opens up a whole loads of other regulations and issues, so you need to be sure when the inspector calls, they don't take exception to them.

I find when seeking approval, it's easier to seek approval before doing the work rather than after

It might also be worth reiterating that the work has passed previous inspections but that this inspector decided that in their opinion it wasn't compliant.

 

[Ric2013]

I think you have to go back to your inspector with that question

I have done this, am waiting for his comment. Mind you, since, when the tenants eventually leave, I will be blocking off the stairs to that poxy room and fit a hatch instead, next time it is inspected, it will not be an issue...

 

[sparkwright]

I GOT IT!

Do the battens and plywood as you wanted, but make sure the width of the thing is no less than about 100 mm.

Drill a 2 or 3 inch diameter hole somewhere in the plywood, then, with short screws, fit a standard electrical blanking plate over the hole.

 

[Ric2013]

Sparkwright

You are a GENIUS!

The blanking plate creates the safe zones. Got it!

 

[JohnW2]

Sparkwright ... You are a GENIUS! .... The blanking plate creates the safe zones. Got it!

'Fraid not - we've been through this one before

Not unreasonably, an accessory only creates a safe zone for a cable connected to it (which most people would accepts includes a situation when there is, say, a connector block behind a blanking plate). If it were not for that twist in the reg, it would be possible to remove the accessory, but leaving the cable in place (now without a safe zone to be in).

Even if a cable creates a safe zone for a cable connected to it, other cables not connected to the accessory theoretically cannot take advantage of that same safe zone - for the same reason (the accessory and connected cable could be removed, leaving the other cable not in a safe zone).

If you wanted to do as has been suggested (and be compliant with regs), you'd have to cut the cable and re-join it (with connector block, Wagos or whatever) in a box behind the blanking plate.

Kind Regards, John

 

[Ric2013]

Even if a cable creates a safe zone for a cable connected to it, other cables not connected to the accessory theoretically cannot take advantage of that same safe zone

Not an issue in this situation.

Not unreasonably, an accessory only creates a safe zone for a cable connected to it (which most people would accepts includes a situation when there is, say, a connector block behind a blanking plate).

Hey... who was it offered me his PVC offcuts that he was going to bin anyway?

The regs are rarely pure and never simple, as Oscar Wilde would have said if he had been an electrician writing "The Importance of Being Earthed"

 

[sparkwright]

I'm not disputing any of what you say above,
but in a safe zone you could have a blanking plate with a live connector block behind it,
but
not a continious piece of cable?

Crazy isn't it?

 

[JohnW2]

Even if a cable creates a safe zone for a cable connected to it, other cables not connected to the accessory theoretically cannot take advantage of that same safe zone

Not an issue in this situation.

I realise that - I was merely mentioning a commonly not realised extension of what I was explaining about the regs.

Not unreasonably, an accessory only creates a safe zone for a cable connected to it (which most people would accepts includes a situation when there is, say, a connector block behind a blanking plate).

Hey... who was it offered me his PVC offcuts that he was going to bin anyway?

Certainly not me

Kind Regards, John

 

[Ric2013]

Lots of issues to consider. Why do you think that, on balance, I previously decided to leave it as it was, clipped direct?

Garr! Oh well, will see what my electrician comes back to me with. Although it may well NOT be him who does the next EICR, so then it's someone else's opinion of what is acceptable. It isn't an HMO, so I don't have a requirement to have a test certificate, it just needs to be safe, and if I manage to address this one issue before I am taken away by the men in white coats, it will be.

If anyone on here is qualified and works as an electrician and wants to take the responsibility of giving me a professional opinion of how this timber trunking can be made not to be a wall and sufficient for purpose (given photos and full details), PM me please, as I may have a job for him or her, if I can't get any sense from my electrician.