I am looking at BS7671 and various commentary books.

It is clear about the 150mm wide acceptable zones near corners and tops
of walls.

It is also clear about vertical and horizontal runs from wiring accessories.

However, on one point, I can't see anything specific.

Consider this case:

- Wiring accessory has horizontal cable run which reaches corner

- On the adjoining wall at the same height, there is another wiring accessory.

- SInce it is permissible to run a cable horizontally from a wiring
accessory, nothing is violated.

Now consider this case:

- Wiring accessory has horizontal cable which reaches corner.

- This time there is not a wiring accessory on the adjoining wall but
after a second corner there is.

- The horizontal runs from each wiring accessory to the nearest corner is OK.

However, what about the middle wall?

Common sense would suggest that running the cable horizontally across
the middle wall is not allowed because there is not a wiring accessory
there.

However, the standard does not appear to be specific on this point.

The only thing I can see is that the opening words of 526-06-06 say

" When a cable is installed in a wall..."

which does suggest a wall by wall view of it, but the point isn't very
explicit.

Comments?

On Fri, 22 Sep 2006 21:55:15 UTC, Andy Hall wrote:

I am looking at BS7671 and various commentary books.

Now consider this case:

- Wiring accessory has horizontal cable which reaches corner.

- This time there is not a wiring accessory on the adjoining wall but
after a second corner there is.

- The horizontal runs from each wiring accessory to the nearest corner is OK.

However, what about the middle wall?

Common sense would suggest that running the cable horizontally across
the middle wall is not allowed because there is not a wiring accessory
there.

However, the standard does not appear to be specific on this point.

It may not be specific, but it would be best to adhere to the principle
of least astonishment!

--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
Avenue Supplies, http://avenuesupplies.co.uk

The message
from Andy Hall contains these words:

However, what about the middle wall?

Common sense would suggest that running the cable horizontally across
the middle wall is not allowed because there is not a wiring accessory
there.

However, the standard does not appear to be specific on this point.

The only thing I can see is that the opening words of 526-06-06 say

" When a cable is installed in a wall..."

which does suggest a wall by wall view of it, but the point isn't very
explicit.

I think you have put your finger on it with "When a cable is installed
in a wall...". You would have to be at least as devious as John Cartmell
to argue that 2 adjacent walls were really one just because they were
contiguous.

One way round your problem would be to put in an unnecessary point on
the middle wall.

I have a ring main running round my kitchen with outlets on 3 walls but
that has to go up to the ceiling (into the void in my case) to get round
a window. One of these days I really must get round to putting up the
ceiling and plastering the walls but I am still undecided on how to
insulate the walls. ;-(

--
Roger Chapman

Andy Hall wrote:

I am looking at BS7671 and various commentary books.

You do have the current (brown) edition? The wording of 522-06-06 was
changed in the most recent amendment[*] and all of 522-06-07 was deleted.
[*] Amendment no. 2, AMD14905 - the one which, primarily, introduced the
new wiring colours.

Now consider this case:

- Wiring accessory has horizontal cable which reaches corner.

- This time there is not a wiring accessory on the adjoining wall but
after a second corner there is.

- The horizontal runs from each wiring accessory to the nearest corner
is OK.

However, what about the middle wall?

Common sense would suggest that running the cable horizontally across
the middle wall is not allowed because there is not a wiring accessory
there.

However, the standard does not appear to be specific on this point.

The only thing I can see is that the opening words of 526-06-06 say

" When a cable is installed in a wall..."

which does suggest a wall by wall view of it, but the point isn't very
explicit.

522-06-06 doesn't refer to "corners" but to "an angle formed by two
adjoining wall or partitions." /Ipso facto/ ISTM that the intent is
that each wall is to be considered separately.

Now if you have curved walls and/or rounded corners the interpretation
could be more interesting...

--
Andy

On 2006-09-23 11:04:52 +0100, Andy Wade said:

Andy Hall wrote:

I am looking at BS7671 and various commentary books.

You do have the current (brown) edition? The wording of 522-06-06 was
changed in the most recent amendment[*] and all of 522-06-07 was
deleted.

[*] Amendment no. 2, AMD14905 - the one which, primarily, introduced
the new wiring colours.

This was the blue one. I should get a brown one, I suppose.

Are there many other significant changes?



522-06-06 doesn't refer to "corners" but to "an angle formed by two
adjoining wall or partitions." /Ipso facto/ ISTM that the intent is
that each wall is to be considered separately.

Now if you have curved walls and/or rounded corners the interpretation
could be more interesting...

Exactly, and these are increasingly common.

I've decided to run cables to the corners then up in the 150mm space,
along in the 150mm space near the ceiling and down again.

The other case, which is not covered is where the wall meets the
ceiling at an angle - e.g. in loft rooms. For this one, I think that
the reasonable interpretation is to have the 150mm zone following the
angle with the ceiling.

Andy Hall wrote:

This was the blue one. I should get a brown one, I suppose.

I'd wait. The 17th Edition is due out early in 2008.

Are there many other significant changes?

Download the update from http://www.iee.org/publish/wireregs/updates.cfm

The other case, which is not covered is where the wall meets the ceiling
at an angle - e.g. in loft rooms. For this one, I think that the
reasonable interpretation is to have the 150mm zone following the angle
with the ceiling.

This came up in another thread recently. I agree, it's a 150 mm wide
zone from the top of the wall and there's nothing that says that the
top, or the zone, has to be horizontal.

--
Andy

Andy Hall wrote:

I've decided to run cables to the corners then up in the 150mm space,
along in the 150mm space near the ceiling and down again.

That would have been my take on the best way to do it.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/