Horizontal safe zone with 'dry lining' back boxes

[Harry Bloomfield]

I see what you mean now, usually there will be space behind so come out the back and then go left or right.

Coming out of the top, or bottom, then across the corner, would only expose a tiny slither of cable at the corner, to the strictly speaking 'none safe zone'. The vertical safe zone begins at the corner of the accessories, and rises vertically from that corner, likewise the horizontal one. However, no one would ever need, or want to drill or nail anything, in that tiny exposed corner.

 

[JohnW2]

I see what you mean now, usually there will be space behind so come out the back and then go left or right.

Sure - as I wrote to Murdo, that's the obvious way - IF there is space behind the box,

 

[pete01]

Coming out of the top, or bottom, then across the corner, would only expose a tiny slither of cable at the corner, to the strictly speaking 'none safe zone'. The vertical safe zone begins at the corner of the accessories, and rises vertically from that corner, likewise the horizontal one. However, no one would ever need, or want to drill or nail anything, in that tiny exposed corner.

True and I suppose anyone would be mad to drill that close in the corner of a socket or switch

 

[JohnW2]

Coming out of the top, or bottom, then across the corner, would only expose a tiny slither of cable at the corner, to the strictly speaking 'none safe zone'.

That's what I wrote in my OP!

We're totally agreed about the common sense, but I was asking what Mr Jobsworth would have to say about it - particularly if he were undertaking an EICR and saw that the cable went out of the top of the box and yet arrived at another accessory horizontally-aligned with the one in question

 

[JohnW2]

However, no one would ever need, or want to drill or nail anything, in that tiny exposed corner.

I certainly can't think how there could ever be a 'need'. However, if you believe that it could never happen, then you must have more faith than I do in the idea that no-one will ever do something completely crazy

 

[JohnW2]

To be honest I only use a fast fix if I really have to you cant beat a metal box on a noggin....

As I've said above. I could not have a noggin, but I do have a brick, and it's that brick which would stop me having rear entry from a dry-lining box. However, what I should have realised in the first place is that the obvious thing to do it screw a met box to the brick!

 

[morqthana]

Slow day in the property renovation project, John?

 

[Risteard]

That's obviously what one would ideally do.

However, as I've said, I personally have never seen a 'dry lining' box with manufactured provision for cable entry at the side. Much of the side is invariably taken up by the 'gripping mechanism', so one could only 'come out of the side' if (as I mentioned in the OP) one could successfully drill a hole near the top of the bottom of the side without damaging something.

Or with top entry only, and not wanting to drill the back, then bend the cable at the top until it ends up behind the dryliner, and then run it horizontally. Then everything is witihin zones (apart from wherever the cable would naturally sag to along the horizontal run). If the cable is at least 50mm from either wall then it's a moot point anyway.

 

[JohnW2]

Slow day in the property renovation project, John?

Very slow - I've been about 100 miles away from it all day

 

[JohnW2]

Or with top entry only, and not wanting to drill the back, then bend the cable at the top until it ends up behind the dryliner, and then run it horizontally. Then everything is witihin zones

As I've explained, I could not do that any more than I could use a hole in the back, because of a brick wall being in the way - but, as I've said, that has made me realise how daft I was being, 'cos the obvious solution is to screw a metal box to the brick.

(apart from wherever the cable would naturally sag to along the horizontal run).

That seems to be one of the silly things about the zones when it comes to stud walls etc. - even with vertical runs, unless the cable were installed and 'clipped' prior to boarding, there's really no telling whether the whole length of the cable will be within the 'zone' it's meant to be within!

If the cable is at least 50mm from either wall then it's a moot point anyway.

True though that statement is, as above, if it's a stud wall, then one will usually have no idea how 'deep' the cable is at any part of its length.

 

[ebee]

That's obviously true, no matter how the accessory is 'attached.

That's not inevitable, and is why I asked the question.

As I said, that bit 'around the corner' would be in neither the horizontal nor vertical zone created by the accessory.

I agree (in terms of common sense) but that's why I said my question related to those who felt that the regs should be 'strictly adhered to'. I've certainly seen occasions when, here and elsewhere, people have been told that cables are 'outside of permitted zones' (hence 'not acceptable) when they are only very slightly outside of the zone!

Well if they are outside the zone then they are outside the zone. Personally I always make sure that they are very comfortably inside the zone but I have seen plenty where they do protrude outside the zone, sometimes alarmingly so,
We need to stick to the rule if it has to have meaning.
I have also encountered an expectation that due to the size and number of conductors present that they “must be in the middle third portion of the zone surely!”
It would be wrong to rely upon that even if it is considered the logical place for it to be.

I would not place much trust in any cheapo detector to reveal the position of buried cables either.

 

[JohnW2]

Well if they are outside the zone then they are outside the zone.

That's why I asked the question, even though some would probably regard it as trivial or even 'pedantic'

Personally I always make sure that they are very comfortably inside the zone but I have seen plenty where they do protrude outside the zone, sometimes alarmingly so,

I suppose that should be one's aim - but, as I've said, in the case of cables installed (without conduit) in stud walls after they have been boarded, one really cannot be very sure where the full run of cable has ended up

We need to stick to the rule if it has to have meaning.

As above, that's obviously the ideal.

I have also encountered an expectation that due to the size and number of conductors present that they “must be in the middle third portion of the zone surely!”

Interesting - but, more realistically (as in the situation I was describing) maybe the zones should extend, say, 30% beyond the edges ofthe accessory creating them?

It would be wrong to rely upon that even if it is considered the logical place for it to be. I would not place much trust in any cheapo detector to reveal the position of buried cables either.

There's clearly no 'foolproof' solution, other than by completely banning (and policing the banning of!) 'concealed cables' (unless in steel conduit). The very small number of cables I have accidentally drilled/nailed/whatever into over the decades have been miles from any 'zone'. Perhaps the most surprising case (which took a good while to investigate and remedy) was in the middle of fairly large wall in a bathroom, with the room literally having no electrical accessories at all on any of its walls (ceiling pull switch for light, and nothing else)

Some common sense also helps. Having seen the evidence of this having been done (evidence of chases) on stripped walls, I usually assume that, although it would be very much non-compliant ('out of zones'), one should be aware of the possibility of a 'diagonal' cable route - for example, between a light switch and a wall light it operates, between an FCU and socket or between a cooker control unit and a 'non-aligned' output plate etc. etc.

Kind Regards, John

 

[ebee]

“Some common sense also helps. Having seen the evidence of this having been done (evidence of chases) on stripped walls, I usually assume that, although it would be very much non-compliant ('out of zones'), one should be aware of the possibility of a 'diagonal' cable route - for example, between a light switch and a wall light it operates, between an FCU and socket or between a cooker control unit and a 'non-aligned' output plate etc. etc.”

Ditto that John

 

[Harry Bloomfield]

That's why I asked the question, even though some would probably regard it as trivial or even 'pedantic'

I think you are being far too 'pendantic' - just a bit of common sense suggests that no one would have a reason to attempt to fix so close to your example socket, or at least if they did, their own common sense ought to suggest to them that they could expect cables to be in the area. If neither option is a deterrent, then likely they would be risking nailing a cable anyway, even if in a safe zone.

Here, I know where all of the cable and pipes runs are, buried in the walls, all are in the zones, but even so I would double-check with a detector, which I do find effective. I have much less knowledge about what's where, under the floors.

 

[JohnW2]

I think you are being far too 'pendantic' - just a bit of common sense suggests that no one would have a reason to attempt to fix so close to your example socket, or at least if they did, their own common sense ought to suggest to them that they could expect cables to be in the area.

I've already agreed about the common sense of that, and it wouldn't personally worry me to have cable routed as I've suggested.

However, as for 'pedantic', and as previously said, I asked the question because I know there are some people who would regard it s anything but 'pedantic', thinking/writing things such as ebee recently did ...

Well if they are outside the zone then they are outside the zone. .... We need to stick to the rule if it has to have meaning.