I'm aware of the rules regarding the appropriate routing of concealed
T&E cables, i.e. within 50mm of wall edges/corners, in vertical or
horizontal lines from a visible electrical accessory or greater than
50mm below a plastered surface. Anything else would require mechanical
protection from drill bits, nails & screws and such like.

I was talking to a fully qualified sparky recently about my planned works.

He claimed that if the cable in question is protected electrically by a
RCBO at the CU, none of the above apply and that if I really wanted to,
I could run T&E in the gap between breeze/block wall and dot 'n' dabbed
plasterboard from floor to ceiling with no mechanical protection at all,
at less than 50mm depth from the surface and totally ignore the above
cable routing rules.

Is the sparky factually correct or talking brown stuff regarding wiring
17th ed regs?

If he is correct, it offers me more cable routing opportunities given
that I'm installing a CU fully populated with RCBOs only particularly
for putting in a lighting circuit for the loft on its own RCBO. (this is
deliberate in case I decide to have a loft conversion in the future so I
was planning ahead regarding circuit design for this eventuality)

Slipping the 1.5mm T&E down between wall and plasterboard from loft to
ground floor is actually an easier route than hacking access panels into
a plasterboarded stud & partition wall, drilling holes in the noggins
and reinstating the plasterboard panel cutouts and re-skimming the wall
in order to have a cable route that obeyed the rules details in the
first paragraph of this post.

Stephen.

On 21/02/2013 23:28, Stephen H wrote:

I'm aware of the rules regarding the appropriate routing of concealed
T&E cables, i.e. within 50mm of wall edges/corners, in vertical or

ITYM 150mm...

horizontal lines from a visible electrical accessory or greater than
50mm below a plastered surface. Anything else would require mechanical
protection from drill bits, nails & screws and such like.

either mechanical or earthed metal shielding; so a SWA may not have 3mm
of steel round it, but the fact that the armour is earthed is adequate
protection.


I was talking to a fully qualified sparky recently about my planned works.

He claimed that if the cable in question is protected electrically by a
RCBO at the CU, none of the above apply and that if I really wanted to,
I could run T&E in the gap between breeze/block wall and dot 'n' dabbed
plasterboard from floor to ceiling with no mechanical protection at all,
at less than 50mm depth from the surface and totally ignore the above
cable routing rules.

Is the sparky factually correct or talking brown stuff regarding wiring
17th ed regs?

Its sounds slightly confused...

You can run cables at less than 50mm depth, and without additional
mechanical protection. However they require RCD protection (with a trip
threshold of = 30mA), and the should be in one of the prescribed zones:

http://wiki.diyfaq.org.uk/index.php?...lectric_cables

So directly up, down, beside a CU fro example would be ok.

If he is correct, it offers me more cable routing opportunities given
that I'm installing a CU fully populated with RCBOs only particularly
for putting in a lighting circuit for the loft on its own RCBO. (this is
deliberate in case I decide to have a loft conversion in the future so I
was planning ahead regarding circuit design for this eventuality)

Slipping the 1.5mm T&E down between wall and plasterboard from loft to
ground floor is actually an easier route than hacking access panels into
a plasterboarded stud & partition wall, drilling holes in the noggins
and reinstating the plasterboard panel cutouts and re-skimming the wall
in order to have a cable route that obeyed the rules details in the
first paragraph of this post.

One option is to cheat - sticking an electrical accessory on the wall at
an appropriate place to create the required zone is one option. That way
you give a clue to someone drilling holes in the future.

However its usually fairly easy to go say up from a CU to a ceiling,
thence across to a corner, and finally up through as many stories as
required to the loft in the corner.


--
Cheers,

John.

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

On Feb 21, 11:51*pm, John Rumm wrote:
On 21/02/2013 23:28, Stephen H wrote:



I'm aware of the rules regarding the appropriate routing of concealed
T&E cables, i.e. within 50mm of wall edges/corners, in vertical or

ITYM 150mm...

horizontal lines from a visible electrical accessory or greater than
50mm below a plastered surface. Anything else would require mechanical
protection from drill bits, nails & screws and such like.

either mechanical or earthed metal shielding; so a SWA may not have 3mm
of steel round it, but the fact that the armour is earthed is adequate
protection.

I was talking to a fully qualified sparky recently about my planned works.

He claimed that if the cable in question is protected electrically by a
RCBO at the CU, none of the above apply and that if I really wanted to,
I could run T&E in the gap between breeze/block wall and dot 'n' dabbed
plasterboard from floor to ceiling with no mechanical protection at all,
at less than 50mm depth from the surface and totally ignore the above
cable routing rules.

Is the sparky factually correct or talking brown stuff regarding wiring
17th ed regs?

Its sounds slightly confused...

You can run cables at less than 50mm depth, and without additional
mechanical protection. However they require RCD protection (with a trip
threshold of = 30mA), and the should be in one of the prescribed zones:

http://wiki.diyfaq.org.uk/index.php?...lectric_cables

So directly up, down, beside a CU fro example would be ok.

If he is correct, it offers me more cable routing opportunities given
that I'm installing a CU fully populated with RCBOs only particularly
for putting in a lighting circuit for the loft on its own RCBO. (this is
deliberate in case I decide to have a loft conversion in the future so I
was planning ahead regarding circuit design for this eventuality)

Slipping the 1.5mm T&E down between wall and plasterboard from loft to
ground floor is actually an easier route than hacking access panels into
a plasterboarded stud & partition wall, drilling holes in the noggins
and reinstating the plasterboard panel cutouts and re-skimming the wall
in order to have a cable route that obeyed the rules details in the
first paragraph of this post.

One option is to cheat - sticking an electrical accessory on the wall at
an appropriate place to create the required zone is one option. That way
you give a clue to someone drilling holes in the future.

However its usually fairly easy to go say up from a CU to a ceiling,
thence across to a corner, and finally up through as many stories as
required to the loft in the corner.

--
Cheers,

John.

I often think the "protection" issue is a load of ********.
After all, the only protection that would actually protect would be
steel conduit.
All this plastic/thin metal tacky stuff won't protect against an
electric drill.

I

On Thursday 21 February 2013 23:28 Stephen H wrote in uk.d-i-y:


I'm aware of the rules regarding the appropriate routing of concealed
T&E cables, i.e. within 50mm of wall edges/corners,


^^^^ 150mm aka 6"

That's internal corners only but also the internal top or wall/ceiling edge
on the wall face too.

in vertical or
horizontal lines from a visible electrical accessory or greater than
50mm below a plastered surface. Anything else would require mechanical
protection from drill bits, nails & screws and such like.

I was talking to a fully qualified sparky recently about my planned works.

He claimed that if the cable in question is protected electrically by a
RCBO at the CU, none of the above apply and that if I really wanted to,
I could run T&E in the gap between breeze/block wall and dot 'n' dabbed
plasterboard from floor to ceiling with no mechanical protection at all,
at less than 50mm depth from the surface and totally ignore the above
cable routing rules.

He's right about the 50mm bit, but he's talking complete ******** about
"ignoring the routing rules".

Any cable that does not have mechanical protection and is less that 50mm
from the surface needs RCD protection.

If the cable has mechanical protection (metal trunking, metal conduit, is
steel wired armoured (or foil screens to a particular standard and other
condition are met) *then* you can route it where you like.

Or if it's on the surface and visible - then again, any way you want.

So with RCD protection at 30mA/40mS covering that circuit, directly or
indirectly, you could run between the PB and wall but you still have to
follow the horizontal/vertical from accessory or internal coner routing.

Is the sparky factually correct or talking brown stuff regarding wiring
17th ed regs?

If he is correct, it offers me more cable routing opportunities given
that I'm installing a CU fully populated with RCBOs only particularly
for putting in a lighting circuit for the loft on its own RCBO. (this is
deliberate in case I decide to have a loft conversion in the future so I
was planning ahead regarding circuit design for this eventuality)

Slipping the 1.5mm T&E down between wall and plasterboard from loft to
ground floor is actually an easier route than hacking access panels into
a plasterboarded stud & partition wall, drilling holes in the noggins
and reinstating the plasterboard panel cutouts and re-skimming the wall
in order to have a cable route that obeyed the rules details in the
first paragraph of this post.

Stephen.
--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage

Reading this on the web? See:
http://wiki.diyfaq.org.uk/index.php?title=Usenet

On Friday 22 February 2013 08:01 harry wrote in uk.d-i-y:

I often think the "protection" issue is a load of ********.
After all, the only protection that would actually protect would be
steel conduit.
All this plastic/thin metal tacky stuff won't protect against an
electric drill.

The regs do define the level of protection.

But you have to remember that as long as the "thin tacky stuff" is properly
earthed, it *will* provide protection as the fuse will blow/breaker trip
with the touch voltage on the tool you banged through the cable not
exceeding 50V for 40mS (IIRC).
--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage

Reading this on the web? See:
http://wiki.diyfaq.org.uk/index.php?title=Usenet

On Friday, February 22, 2013 8:01:02 AM UTC, harry wrote:


I often think the "protection" issue is a load of ********.
After all, the only protection that would actually protect would be
steel conduit.

All this plastic/thin metal tacky stuff won't protect against an
electric drill.

It depends on the type of bit. I think thin metal or certain plastics might protect against a masonry bit, which is what someone would be using to drill into the wall. Masonry bits are not sharp.

I once drilled into a wall and found I reached a point where I could drill no further. I tried drilling for a long time getting nowhere and finally discovered there was a cable there behind a thin metal strip.

Robert

On 22/02/2013 08:01, harry wrote:


I often think the "protection" issue is a load of ********.
After all, the only protection that would actually protect would be
steel conduit.
All this plastic/thin metal tacky stuff won't protect against an
electric drill.


Steel conduit won't protect you from a Bosch multi-material drill.
They go through steel easier than the brick/block.

However conduit should be earthed and stop you getting shocked.

In article m,
dennis@home scribeth thus
On 22/02/2013 08:01, harry wrote:


I often think the "protection" issue is a load of ********.
After all, the only protection that would actually protect would be
steel conduit.
All this plastic/thin metal tacky stuff won't protect against an
electric drill.


Steel conduit won't protect you from a Bosch multi-material drill.
They go through steel easier than the brick/block.

However conduit should be earthed and stop you getting shocked.


Den .. would you really be going into brick and or masonry with a drill
capable of drilling steel and do you really have metal cutting masonry
bits;?..
--
Tony Sayer

On 22/02/2013 08:01, harry wrote:

I often think the "protection" issue is a load of ********.
After all, the only protection that would actually protect would be
steel conduit.

All this plastic/thin metal tacky stuff won't protect against an
electric drill.

Plastic / thin metal capping is really only designed to protect cables
from the over exuberance of the plasterer.

If you want failsafe electrical protection, then you need an earthed
screen round the cable.


--
Cheers,

John.

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

On 22/02/2013 18:08, tony sayer wrote:
In article m,
dennis@home scribeth thus
On 22/02/2013 08:01, harry wrote:


I often think the "protection" issue is a load of ********.
After all, the only protection that would actually protect would be
steel conduit.
All this plastic/thin metal tacky stuff won't protect against an
electric drill.


Steel conduit won't protect you from a Bosch multi-material drill.
They go through steel easier than the brick/block.

However conduit should be earthed and stop you getting shocked.


Den .. would you really be going into brick and or masonry with a drill
capable of drilling steel and do you really have metal cutting masonry
bits;?..


Why not?
They drill masonry easily without needing to turn on hammer and hence
make the drill last longer.

http://www.toolstation.com/shop/Powe.../sd1350/p51204

On 22/02/2013 09:36, Tim Watts wrote:

[safe zones, 150 mm etc.]
That's internal corners only

Uh? How does "... or within 150 mm of an angle formed by two adjoining
walls or partitions" [1] rule out external corners?


[1] BS 7671 reg. 522.6.6

--
Andy

On Friday 22 February 2013 23:20 Andy Wade wrote in uk.d-i-y:

On 22/02/2013 09:36, Tim Watts wrote:

[safe zones, 150 mm etc.]
That's internal corners only

Uh? How does "... or within 150 mm of an angle formed by two adjoining
walls or partitions" [1] rule out external corners?


[1] BS 7671 reg. 522.6.6


Probably because that's how the diagrams I've seen present it - I've not
bothered to actually check the wording.

I shall do so tomorrow and double check the On Site Guide.


--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage

Reading this on the web? See:
http://wiki.diyfaq.org.uk/index.php?title=Usenet

On Fri, 22 Feb 2013 18:08:16 +0000, tony sayer wrote:

Steel conduit won't protect you from a Bosch multi-material drill.
They go through steel easier than the brick/block.

Den .. would you really be going into brick and or masonry with a drill
capable of drilling steel and do you really have metal cutting masonry
bits;?..

You've not come across the Bosch multi drills then? They do drill
virtually anything, light metal capping wouldn't be any challange at all,
unlike a normal masonary drill. Conduit will make it think a bit but it's
just an 'ard brick innit...

--
Cheers
Dave.

In article om,
dennis@home scribeth thus
On 22/02/2013 18:08, tony sayer wrote:
In article m,
dennis@home scribeth thus
On 22/02/2013 08:01, harry wrote:


I often think the "protection" issue is a load of ********.
After all, the only protection that would actually protect would be
steel conduit.
All this plastic/thin metal tacky stuff won't protect against an
electric drill.


Steel conduit won't protect you from a Bosch multi-material drill.
They go through steel easier than the brick/block.

However conduit should be earthed and stop you getting shocked.


Den .. would you really be going into brick and or masonry with a drill
capable of drilling steel and do you really have metal cutting masonry
bits;?..


Why not?
They drill masonry easily without needing to turn on hammer and hence
make the drill last longer.

http://www.toolstation.com/shop/Powe...ll+Bits/Multi+
Construction+TCT+Drill+Bit+Set+4+Piece/d80/sd1350/p51204

Tried those a while ago and wasn't that impressed...
--
Tony Sayer

Tim Watts wrote:
On Friday 22 February 2013 23:20 Andy Wade wrote in uk.d-i-y:

On 22/02/2013 09:36, Tim Watts wrote:

[safe zones, 150 mm etc.]
That's internal corners only

Uh? How does "... or within 150 mm of an angle formed by two
adjoining walls or partitions" [1] rule out external corners?


[1] BS 7671 reg. 522.6.6


Probably because that's how the diagrams I've seen present it - I've
not bothered to actually check the wording.

I shall do so tomorrow and double check the On Site Guide.

The OSG gives no further info.

John Rumm updated

http://wiki.diyfaq.org.uk/index.php?...lectric_cables

last year to show external corners after we had discussed the external wall
angles/corners issue. We did take guidance from a registered body before
John drew the picture.


The only thing missing from
http://wiki.diyfaq.org.uk/images/c/cf/Cablezones1.jpg is the flat screen TV
on the wall:-)


--
Adam

On Sunday 24 February 2013 04:44 ARW wrote in uk.d-i-y:

Tim Watts wrote:
On Friday 22 February 2013 23:20 Andy Wade wrote in uk.d-i-y:

On 22/02/2013 09:36, Tim Watts wrote:

[safe zones, 150 mm etc.]
That's internal corners only

Uh? How does "... or within 150 mm of an angle formed by two
adjoining walls or partitions" [1] rule out external corners?


[1] BS 7671 reg. 522.6.6


Probably because that's how the diagrams I've seen present it - I've
not bothered to actually check the wording.

I shall do so tomorrow and double check the On Site Guide.

The OSG gives no further info.

John Rumm updated

http://wiki.diyfaq.org.uk/index.php?...lectric_cables

last year to show external corners after we had discussed the external
wall angles/corners issue. We did take guidance from a registered body
before John drew the picture.


OK - That's interesting - thank you.

I may be remembering back to a diagram in one of John Whitfield's Pocket
guides - which would have been an earlier edition.

Personally, I'm not hugely keen on either corner route as the average person
has enough trouble not banging a picture hook in directly inline with an
accessory - but there you go. Mind you I have made use of the ceiling band
when a conduit had to deviate around an obstruction.

--
Tim Watts Personal Blog: http://squiddy.blog.dionic.net/

http://www.sensorly.com/ Crowd mapping of 2G/3G/4G mobile signal coverage

Reading this on the web? See:
http://wiki.diyfaq.org.uk/index.php?title=Usenet

Tim Watts wrote:
On Sunday 24 February 2013 04:44 ARW wrote in uk.d-i-y:

Tim Watts wrote:
On Friday 22 February 2013 23:20 Andy Wade wrote in uk.d-i-y:

On 22/02/2013 09:36, Tim Watts wrote:

[safe zones, 150 mm etc.]
That's internal corners only

Uh? How does "... or within 150 mm of an angle formed by two
adjoining walls or partitions" [1] rule out external corners?


[1] BS 7671 reg. 522.6.6


Probably because that's how the diagrams I've seen present it -
I've not bothered to actually check the wording.

I shall do so tomorrow and double check the On Site Guide.

The OSG gives no further info.

John Rumm updated

http://wiki.diyfaq.org.uk/index.php?...lectric_cables

last year to show external corners after we had discussed the
external wall angles/corners issue. We did take guidance from a
registered body before John drew the picture.


OK - That's interesting - thank you.

I may be remembering back to a diagram in one of John Whitfield's
Pocket guides - which would have been an earlier edition.

Personally, I'm not hugely keen on either corner route as the average
person has enough trouble not banging a picture hook in directly
inline with an accessory - but there you go.


I did a job a couple of weeks ago. The guy had tried to fit a battery
powered smoke alarm on the landing. Of all the places to fit the alarm he
decided to fit it just under the CU (the CU was close up to the ceiling).

Christ knows why he he tried to fit it there as mounting it on the ceiling
would not have needed the drill or the renewal of the cable he destroyed:-)

--
Adam

Dave Liquorice wrote:
On Fri, 22 Feb 2013 18:08:16 +0000, tony sayer wrote:

Steel conduit won't protect you from a Bosch multi-material drill.
They go through steel easier than the brick/block.

Den .. would you really be going into brick and or masonry with a
drill capable of drilling steel and do you really have metal
cutting masonry bits;?..

You've not come across the Bosch multi drills then? They do drill
virtually anything, light metal capping wouldn't be any challange at
all, unlike a normal masonary drill. Conduit will make it think a bit
but it's just an 'ard brick innit...

Blunt after 2 holes.

--
Adam