Fixing cable to poor base

[Mike2007]

What solution could be made to fix cable on a Domestic re-wire to a very poor base (rubbley wall). Before the wall is rendered over.
I was thinking of fixing 6mm ply to the safe zones as a start and firm base?

Also, if its not possible to drill more than 50mm from top of joist or 50mm from the bottom (joist too thin), would it still be ok in the center of the joist with 30mA RCD protecting a potencial electrical fault?

 

[Spark123]

I suppose you could fix something like that or use conduit.

If you can't make it 50mm then you need to provide additional protection against penetration by nails, screws etc i.e. use metal plates on the joists.

 

[electronicsuk]

Also, if its not possible to drill more than 50mm from top of joist or 50mm from the bottom (joist too thin), would it still be ok in the center of the joist with 30mA RCD protecting a potencial electrical fault?

Do you really mean a joist, or are you referring to studs in a stud wall? If you really have come across such a small joist then it's probably in the loft, in which case you shouldn't be drilling it at all.

 

[Mike2007]

Also, if its not possible to drill more than 50mm from top of joist or 50mm from the bottom (joist too thin), would it still be ok in the center of the joist with 30mA RCD protecting a potencial electrical fault?

Do you really mean a joist, or are you referring to studs in a stud wall? If you really have come across such a small joist then it's probably in the loft, in which case you shouldn't be drilling it at all.

In many country property's (farm cottages, buildings) you can regularly get 3 inch joists in first floor and yes they are springy!

 

[Mike2007]

I suppose you could fix something like that or use conduit.

If you can't make it 50mm then you need to provide additional protection against penetration by nails, screws etc i.e. use metal plates on the joists.

So would it be best to stay out of the joists and keep to the walls in the 150mm zones instead?
I thought cables were covered by the RCD protection when they are less than 50mm deep??

 

[RF Lighting]

It is a requirement for cables buried less than 50mm deep from the surface of a wall or partition to be RCD protected*

Cables should not be installed less than 50mm from the top or bottom of a floor joist, regardless of whether it is RCD protected or not, unless as has already been mentioned, you install metal plates to the joists to prevent penetration on nails and screws.

 

[Mike2007]

It is a requirement for cables buried less than 50mm deep from the surface of a wall or partition to be RCD protected*

Cables should not be installed less than 50mm from the top or bottom of a floor joist, regardless of whether it is RCD protected or not, unless as has already been mentioned, you install metal plates to the joists to prevent penetration on nails and screws.

So its wise to stay away from thin joists in favour of safe zones or in a stud wall cavity.
Strange how timbers are subject to this rule when you could easily put a nail the wall with a cable in it?

 

[ban-all-sheds]

The rules are consistent - cables should not be less than 50mm from a surface which might be nailed/screwed/drilled unless they are in a recognised zone, i.e. in-line with accessories, near ceilings, in corners. There are no zones for floors, that's all.

Re your cable fixing problem - how many have you got to get up the wall? Would conduit not do the trick?