concealed cables to D.B.

[jonallcock]

Hi All..

Situation: Full rewire of a house, The distribution board is located in the garrage on the adjacent wall back to back with the house.. The roof level of the garage is below the ceiling of the joists so can't break threw at high level

It's my intention to run the cables down/up the internal wall and punch threw into the back of the garage D.B..

Question: The cables are not in ' permitted cable routes' as per the regs fig 3 (150mm ruling) .. I was going to sink the cables and plate over with one 3/4mm Steel and earth it as a means of mechanical protection..

all circuit RCD protected..

Doing the above I must meet the requirement below:

522.6.6 A cable concealed in a wall or partition at a depth of less than 50 mm from a surface of the wall or partition shall: (i) incorporate an earthed metallic covering which complies with the requirements of these
be mechanically protected against damage sufficient to prevent penetration of the cable by nails, screws and the like,

Any thoughts ??

Jon

 

[Pete999]

Do the cables need to be buried? I would bet the distance you talking about isn't far. One solution would be to put some PVC trunking in to where you need to punch through, not an ideal method but less hassle and you use some decent trunking finishing it off with an end cap, just a thought.

 

[Deleted member 26818]

Nothing wrong with covering the cables with 3/4mm steel plate.
There is no requirement for the steel plate to be earthed.

 

[jonallcock]

Do the cables need to be buried? I would bet the distance you talking about isn't far. One solution would be to put some PVC trunking in to where you need to punch through, not an ideal method but less hassle and you use some decent trunking finishing it off with an end cap, just a thought.

Thanks for your reply..trunking is not an option as it's in the main hallway adjacent to the door

 

[jonallcock]

Nothing wrong with covering the cables with 3/4mm steel plate.
There is no requirement for the steel plate to be earthed.

Thanks for your reply..noted about the earth.. cheers

 

[Pete999]

Thanks for your reply..noted about the earth.. cheers

OK Mate thanks for the reply

 

[Wilko]

Devilish thought - create a permitted zone with an outlet 450 (say) off the floor. Would that work? Cheers

 

[Midwest]

Or put the CU somewhere else . As an aside, never like em in garages, going out in the middle of the night tripping over things to reset the flipping rcd.

PS would you plaster over the steel plate?

 

[telectrix]

spinlondon is correct re no need to earth a steel protective plate. wilko's idea is genius.

 

[Midwest]

Bet someone still comes along and puts a shelf above though

 

[The Ghost]

Could you bring the CU indoors?

 

[jonallcock]

Devilish thought - create a permitted zone with an outlet 450 (say) off the floor. Would that work? Cheers

Thanks... Mmmm I'll have to see where the rad is going but this would work !!!

 

[jonallcock]

Could you bring the CU indoors?

Can't it would look horrendous as it in the hall and they are very particular

 

[jonallcock]

Or put the CU somewhere else . As an aside, never like em in garages, going out in the middle of the night tripping over things to reset the flipping rcd.

PS would you plaster over the steel plate?

Yes- skim finished..I agree about putting not putting them in garage..I was thinking of installing an EM light put that opens another box of worms!!!

 

[The Ghost]

Fish the cables through the cavity wall if you have one?

 

[telectrix]

possibly find the existing cables enter the cavity and go up a couple of feet then come out under floor. if so, they could be used as draw wires.

 

[Midwest]

Cables in cavities, whatever next. Let the cavity debate begin

 

[Deleted member 26818]

Already have a prescribed zone formed by the CU.

 

[telectrix]

not on the reverse side of a cavity wall.

 

[The Ghost]

not on the reverse side of a cavity wall.

Dohh! yeh but where did they route the existing wiring?

 

[Midwest]

Dohh! yeh but where did they route the existing wiring?

In the cavity probably

 

[Taylortwocities]

Cables in cavities, whatever next. Let the cavity debate begin

Ok. For THIS application, IF it is a cavity wall, it will be an internal one -between the garage and the hall - so there's no probs with bridging cavity/transference of damp etc.

 

[jonallcock]

Already have a prescribed zone formed by the CU.

good point...so it does not matter if the apparatus (socket/switch/CU) is on the other side of the wall as the zone is multi-dimensional ?

 

[jonallcock]

Dohh! yeh but where did they route the existing wiring?

On the internally wall clipped direct and capped back entry to the CU.. Approx 30 years ago

 

[telectrix]

brick out behind CU. brick out under upstairs floor. "up and under".

 

[Midwest]

On the internally wall clipped direct and capped back entry to the CU.. Approx 30 years ago

If its a rewire, still might think of relocating CU somewhere more accessible, as long as customer willing to pay for new supply distribution circuit IMO

 

[westward10]

Nothing wrong with covering the cables with 3/4mm steel plate.
There is no requirement for the steel plate to be earthed.

Am I being dumb, why won't the plate need earthing?

 

[telectrix]

Am I being dumb, why won't the plate need earthing?

read 522.6.101. basically, it' s not an exposed conductive part of the installation.

 

[Midwest]

Reg 522.6.204 (iv) mechanical protection.

PS, but the Sunday afternoon DIY'er, won't let a 3mm steel plate stop them from putting up a shelf!

 

[westward10]

Yeah being dumb was thinking it was earthed protection for cables should someone drill through them but they will/should have rcd protection.

 

[Deleted member 26818]

You need to ask the purpose of earthing in this particular instance.
No this is an option that does not include RCD protection.

 

[Wilko]

Reg 522.6.204 (iv) mechanical protection.

PS, but the Sunday afternoon DIY'er, won't let a 3mm steel plate stop them from putting up a shelf!

Maybe suggest a nice dado rail of this stuff?

Sorry, feeling cheeky this arvo ...

 

[Octopus]

The simplest answer is to have a 2g socket in the hall and this would create about ,8 inches of safe zone to the ceiling.

Job done

 

[Deleted member 26818]

Would also mean that the cables would require RCD protection.

 

[Octopus]

Would also mean that the cables would require RCD protection.

So what's the problem with that.... Who does a rewire without RCD protection in a domestic property?

 

[Deleted member 26818]

Me.
I would not install an up front 30mA RCD unless I had no other option.

 

[Octopus]

Me.
I would not install an up front 30mA RCD unless I had no other option.

Who said anything about a single upfront RCD? That wouldn't comply with the regs. RCBO board every time for me!

 

[Deleted member 26818]

Sorry, from the OP's initial post, I thought he was talking about cables supplying the CU.

 

[Deleted member 26818]

Not sure this can be treated as an internal cavity wall?
It may be that the garage is just a leanto added on to the exterior of the house.

 

[7029 dave]

brick out behind CU. brick out under upstairs floor. "up and under".

Eddie wearing.