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Protecting wires in Wall
stevebubs - 22/2/21 at 03:37 PM

Remodelling the kitchen and dining room at the moment, including relocating sockets on the right main and light switches.

What is the accepted way of protecting these wires when we plaster over them?

They will be covered by an RCD but would prefer something over the top as well - was considering putting in metal capping over them but unsure whether it would have needed to be earth bonded.


nick205 - 22/2/21 at 04:09 PM

First off, I'm not an electrician or qualified as such.


In my previous house the wires were covered with plastic trunking like this:

https://www.wickes.co.uk/Wickes-P VC-Protective-Channelling---White-25-x-8mm-x-2m/p/710898?utm_source=google&utm_medium=cpc&adpos=&scid=scplp710898&sc_intid=710898& gclid=EAIaIQobChMIrLiSqe797gIV2-3tCh0sWwWwEAQYASABEgIY_vD_BwE&gclsrc=aw.ds


My current house is timber framed so the wires run the within stud walls.


IIRC the wires are supposed to run verstically and horizontally, not diagonally. Diagonally run wires are too easy to drill into.


Above all make sure you comply with the relevant rules and regulations. It's advisable to seek the services of a qualified electrician.


theconrodkid - 22/2/21 at 05:34 PM

as above ^^^ wires go verticaly or horizontally, i would use conduit as there is a chance or removing / replacing it should a problem arise later on.


harmchar - 22/2/21 at 06:09 PM

Don't want to come across as a smart arse, but the fact questions are being asked about electrical protection, surely means you are not qualified to do the upgrade.
https://www.electricalsafetyfirst.org.uk/find-an-electrician/building-regulations/england/
Might get some advice on above link. It's different rules for you guys in England, but I'm sure you have to have knowledge of Part P before you carry out any electrical work to your property.
At the end of the day, it's all about doing it safely.


cliftyhanger - 22/2/21 at 07:39 PM

quote:
Originally posted by stevebubs
Remodelling the kitchen and dining room at the moment, including relocating sockets on the right main and light switches.

What is the accepted way of protecting these wires when we plaster over them?

They will be covered by an RCD but would prefer something over the top as well - was considering putting in metal capping over them but unsure whether it would have needed to be earth bonded.


protected by being either 50mm+ deep, 3mm of steel and/or an RCD. As above, only vertical or horizontal runs.
Good practice to use capping, PVC is ok, you are not trying to protect the wires from screws/nails, only idiots And the RCD makes sure they don't die.


SteveWalker - 23/2/21 at 12:00 AM

Not only just horizontal and vertical runs, but they must run horizontally or vertically to or from an accessory or within 150mm of a corner of a wall or the top of the wall.

So up from under the floor to a socket, then across to another socket and then back down under the floor is fine; as is up or down to a lightswitch, horizontally from the switch and turning 90° straight up to a wall-light, but not horizontally from a switch, then 90° up, then horizontal again to the wall-light.

Basically anyone doing work in the future should expect cabling at either end or the top of a wall or running horizontally or vertically to or from any accessory and everywhere else should be safe to knock nails in.


nick205 - 23/2/21 at 09:02 AM

quote:
Originally posted by harmchar
Don't want to come across as a smart arse, but the fact questions are being asked about electrical protection, surely means you are not qualified to do the upgrade.
https://www.electricalsafetyfirst.org.uk/find-an-electrician/building-regulations/england/
Might get some advice on above link. It's different rules for you guys in England, but I'm sure you have to have knowledge of Part P before you carry out any electrical work to your property.
At the end of the day, it's all about doing it safely.



Not smart arse at all - as you rightly say it's all about being safe. Both for you and anyone living in or around the property in future. Never anything wrong with paying for the qualified services of an electrician/plumber etc. when needed.


tegwin - 23/2/21 at 02:50 PM

I have just finished a DIY rewire of my house including kitchen etc. Following the 18th edition regs. Signed off by local building inspector...all legal and above board!

There is actually no requirement in the regs for any mechanical protection on an RCD protected cable. I tried plastic capping and metal capping and both are so flimsey I doubt they would do anything to stop a gorilla with a power-tool going through them... Only benefit I can see is to protect the wires from the plasterers float!

Key is to put wires in the permitted zones... as mentioned above so you have a good chance of guessing where they are in the future.


pigeondave - 23/2/21 at 03:17 PM

quote:
Originally posted by tegwin
I have just finished a DIY rewire of my house including kitchen etc. Following the 18th edition regs. Signed off by local building inspector...all legal and above board!

There is actually no requirement in the regs for any mechanical protection on an RCD protected cable. I tried plastic capping and metal capping and both are so flimsey I doubt they would do anything to stop a gorilla with a power-tool going through them... Only benefit I can see is to protect the wires from the plasterers float!

Key is to put wires in the permitted zones... as mentioned above so you have a good chance of guessing where they are in the future.


Does having the wires behind the hardwall (plaster) satisfy the fixing requirement for part 18?

I know from looking at the garage wiring that you have to use non-combustible metal clips now when running wire about the walls, but this could be more towards conduit.

The old plastic conduit clips are no longer allowed, something about fire fighters getting zapped when entering buildings.

OP
I'd also be weary about making the chases too deep. There is advice out there on maximum depth of chases vs wall thickness.
As other have said a bit of top hat plastic should do it. Thats what i've seen on site in the past.


SteveWalker - 23/2/21 at 03:41 PM

Yes. Metal clips are required for surface mounted wiring, wiring fasted to the underside of cable tray and so on, but only to prevent *PREMATURE* collapse. Plasterboard ceilings and walls are specified as a fire-break for a fixed period, so once these have collapsed, falling wires are no longer premature and do not need to be protected against.


pigeondave - 23/2/21 at 03:53 PM

quote:
Originally posted by SteveWalker
Yes. Metal clips are required for surface mounted wiring, wiring fasted to the underside of cable tray and so on, but only to prevent *PREMATURE* collapse. Plasterboard ceilings and walls are specified as a fire-break for a fixed period, so once these have collapsed, falling wires are no longer premature and do not need to be protected against.


Ah good to know, thanks


stevebubs - 24/2/21 at 10:49 AM

quote:
Originally posted by tegwin
I have just finished a DIY rewire of my house including kitchen etc. Following the 18th edition regs. Signed off by local building inspector...all legal and above board!

There is actually no requirement in the regs for any mechanical protection on an RCD protected cable. I tried plastic capping and metal capping and both are so flimsey I doubt they would do anything to stop a gorilla with a power-tool going through them... Only benefit I can see is to protect the wires from the plasterers float!

Key is to put wires in the permitted zones... as mentioned above so you have a good chance of guessing where they are in the future.


Thanks, Tegwin. This is all the confirmation I needed. All the wires are run properly in the safe zones. However I'm also covering them with capping to prevent damage from a plasterer's trowel.

For the rest - reading the regs, I understood that, if they're not 50mm deep, they should be either mechanically protected OR protected by RCD and was looking for validation, not a dressing down.

All work will be signed off by a qualified electrician.

WRT Metal clips - plastic ones are still allowed, but the metal ones are required to slow the collapse (prevent premature failure) causing wires to fall into escape routes). These were introduced as part of the 18th Ed regs.

[Edited on 24/2/21 by stevebubs]


stevebubs - 24/2/21 at 10:52 AM

quote:
Originally posted by cliftyhanger
quote:
Originally posted by stevebubs
Remodelling the kitchen and dining room at the moment, including relocating sockets on the right main and light switches.

What is the accepted way of protecting these wires when we plaster over them?

They will be covered by an RCD but would prefer something over the top as well - was considering putting in metal capping over them but unsure whether it would have needed to be earth bonded.


protected by being either 50mm+ deep, 3mm of steel and/or an RCD. As above, only vertical or horizontal runs.
Good practice to use capping, PVC is ok, you are not trying to protect the wires from screws/nails, only idiots And the RCD makes sure they don't die.


Cheers - just the confirmation I needed.