Cable zones in studwork

[sparkwright]

A comment on a recent thread reminded me how cable zones should apply to studwork just as much as solid walls.

It seems this can get overlooked, especially when dry-line boxes are fitted later after the boarding has been done, and the location of cables running through noggins and uprights has been forgotten.

I take care to drill holes through the timbers so they are in-line with the future accessories, but many electricians don't.

Most studwork won't quite allow the cable to be more than 50mm deep from the finished surface, though very close.

In new houses and the like, I don't think clipping cables to the timberwork is a good idea, as this can seriously bugger up the safe zones.

 

[JohnW2]

It doesn't seem to often get mentioned/discussed, but particularly in the case of vertical cable runs/drops in stud walls, if, as is usual, the cable is not clipped to any of the timbers, and if (as also usual) there is at least a bit of slack in the cable, one cannot really be certain that tehhe cable remains within 'safe zones' for its entire length - particularly the narrow 'safe zone' created by a 'single width' accessory (switch, single socket, FCU etc.).

Kind Regards, John

 

[John D v2.0]

Johnw2 I thought if the cable was loose eg on a ceiling, then that was ok, it was only where it passed through a joist or stud
This is because any drill or screw would just push it aside

 

[JohnW2]

Johnw2 I thought if the cable was loose eg on a ceiling, then that was ok, it was only where it passed through a joist or stud. This is because any drill or screw would just push it aside

There are no safe zones in ceilings.

As for cables in walls, the regulations about safe zones etc. relate to "a cable installed in a wall or partition at a depth of less than 50mm from the surface of the wall" - and I have always assumed (particularly because of the "partition" bit) that this relates to stud/'partition' walls just as much as to solid ones - but maybe I have always been wrong!

Whilst, as you say, a drill, screw, nail or whatever would probably 'push the cable aside' without damaging that, I don't think that could be guaranteed. I can confess that I once massacred an (unexpected) cable when, rather lazily, using a jigsaw on the plasterboard of a stud wall, in a place that didn't qualify as a safe zone!

Kind Regards, John

 

[Adam_151]

It seems this can get overlooked, especially when dry-line boxes are fitted later after the boarding has been done, and the location of cables running through noggins and uprights has been forgotten.

The best to avoid that, is to fit metal knockout boxes at first fix stage, rather than have a session of sawing in dryline boxes between first and second fix. Make sure the lip of the box extends beyond the studs 10mm or so. That way the boarders have to cut out for it, rather than 'forgetting' it. Of course if they are **** boarders are still able to do the 'massive hole that gets bunged up with filler and painted, but drops out when you unscrew the point to test' trick, but decent ones are able to use a tape measure and striaght edge.

I see dryline boxes as being more for existing stud walls, rather than new construction.

 

[ban-all-sheds]

A comment on a recent thread reminded me how cable zones should apply to studwork just as much as solid walls.

They do.

It seems this can get overlooked, especially when dry-line boxes are fitted later after the boarding has been done, and the location of cables running through noggins and uprights has been forgotten.

Anybody who installs cables which are not in a prescribed zone has contravened the Wiring Regulations, and given the safety implications has probably committed a criminal offence in England and Wales.

I take care to drill holes through the timbers so they are in-line with the future accessories, but many electricians don't.

See above comment.

In new houses and the like, I don't think clipping cables to the timberwork is a good idea, as this can seriously bugger up the safe zones.

See above comment.

ATEOTD, the wall construction makes b****r-all difference to the rules for locating cables, and nobody who allows any characteristics of a type of construction to create non-compliances should be working as an electrician.

 

[JohnW2]

As I have observed, those (presumably including most electricians) who have ever installed significantly long vertical runs of cables in stud walls are unlikely, in many cases, to have a clue as to whether or not that cable remains totally within 'safe zones for it's full length - but I don't think I would go as far as saying that none of them should be working as electricians for that reason.

 

[ban-all-sheds]

Unless you can find a regulation which allows a cable to be outside of a safe zone because it is hanging free, then any electrician who declares that he has complied when in reality he does not have a clue if he has should indeed not, IMO, be working as one.

Other people may have lower standards.