Cable zone 150mm from internal corner

[sparkwright]

Scenario A.

Two small knocked into one big room.

Adjoining wall gets taken down.

What happens if there were cables concealed in the plaster 150mm from the corner, still in situ in the remaining wall?

There would be four 150mm wide strips in this big room which could potentially contain concealed cables.

They wouldn't necessarily run all the way from ceiling to floor either, so no ****-proof way of checking, other than removing the plaster.

 

[JohnW2]

What happens if there were cables concealed in the plaster 150mm from the corner, still in situ in the remaining wall?

I think you know the answer - they would no longer be in 'safe zones'.

There would be four 150mm wide strips in this big room which could potentially contain concealed cables. They would necessarily run all the way from ceiling to floor either, so no ****-proof way of checking, other than removing the plaster.

Indeed - and assuming you don't have faith in 'cable detectors', there is probably no totally foolproof non-destructive way of finding out. Mind you, if you have access to the spaces below the floor and above the ceiling, you could become pretty sure whether or not any cables were travelling in those 'previous safe zones'.

Kind Regards, John

 

[sparkwright]

Mind you, if you have access to the spaces below the floor and above the ceiling, you could become pretty sure whether or not any cables were travelling in those 'previous safe zones'.

But if a cable can be placed anywhere in that 150mm strip you may not necessarily see it from under the floor or above the ceiling.

 

[JohnW2]

But if a cable can be placed anywhere in that 150mm strip you may not necessarily see it from under the floor or above the ceiling.

That's why I said 'pretty sure', rather than 'certain'. It depends to some extent upon the presence or absence of any accessories on that (previous) wall. If there were no such accessories, then there could only have been previously compliant cables in that 'safe zone' if they ran all the way from top to bottom.

Furthermore, unless one starts thinking about fairly silly cable routes, even if there were accessories on the wall, then it would probably uually only make sense to run cables from them to that 'safe zone' if they were then going to travel to either the top or bottom of the wall - so, again, I think the absence of any cables wither above or below the wall would make one 'pretty sure', albeit not certain.

Kind Regards, John

 

[sparkwright]

I certainly could think of various silly cable routes that could take place within a 150mm strip, with part of the run being drilled through the wall onto the other side.

Or a cable running horizontally within 150mm of the ceiling, then at a right angle down in the corner zone we are discussing.

But I won't go on about those too much.

The point is, is something is allowed - like running cables within 150mm of an internal corner, then anything could happen if it makes life easier for the electrician or whatever other reason.

Thing is, no one's ever taken a wall down and asked me to inspect for cables on the remaining walls.

 

[JohnW2]

I certainly could think of various silly cable routes that could take place within a 150mm strip, with part of the run being drilled through the wall onto the other side. ... Or a cable running horizontally within 150mm of the ceiling, then at a right angle down in the corner zone we are discussing. ... But I won't go on about those too much.

Yes, and so can I - and that's why one can't be certain.

Thing is, no one's ever taken a wall down and asked me to inspect for cables on the remaining walls.

I'm not surprised, and that's probably simply because it doesn't occur to hardly anyone (probably including most builders etc.) to even think about the issue you're highlighting.

I think this just reinforces the fact that, whilst one knows that there might be cables in (current) 'safe zones', one certainly cannot assume that there are not any cables that are not in 'safe zones'. Like many people, I have certainly encountered cables (mainly out-of-service, but occasionally in-service) in places that are not designated 'safe zones'. I also wonder when the 'safe zone' concept first appeared in the regs?

Kind Regards, John

 

[Jackrae]

How gave the 'spark regulators' the right to deny shelf and cupboard fixers the possibility of fixing things within 150mm of an internal corner

 

[JohnW2]

How gave the 'spark regulators' the right to deny shelf and cupboard fixers the possibility of fixing things within 150mm of an internal corner

Well, I think that a good few of us feel that it's a fairly daft place to allow a 'safe zone', since it's a pretty likely place for wanting to fix all sorts of wall-mounted things!

Kind Regards, John

 

[ban-all-sheds]

Thing is, no one's ever taken a wall down and asked me to inspect for cables on the remaining walls.

No - because taking down walls is not within the scope of BS 7671.

When the cables were installed that had to be done in compliance with BS 7671. There is no requirement to re-inspect/test when something non-electrical is done.

 

[JohnW2]

When the cables were installed that had to be done in compliance with BS 7671. There is no requirement to re-inspect/test when something non-electrical is done.

Indeed there isn't - and that merely further reduces the value of the concept of 'safe zones' - a concept which I suspect has the potential to do more harm than good.

Kind Regards, John

 

[ban-all-sheds]

If a builder took the wall down then he should have checked. I am in no doubt that that would have been the requisite duty of care which he, as a professional, owed his client.