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Default Consumer Units with RCBOs

On Thu, 30 May 2019 18:22:17 +0100, John Rumm wrote:

On 30/05/2019 08:19, PeterC wrote:
On Wed, 29 May 2019 21:27:25 +0100, ARW wrote:

On 29/05/2019 11:41, Tricky Dicky wrote:
The wall where the garage supply cable will be buried in the wall is an exterior cavity wall with the internal wall being cinder type breeze blocks so quite easy to chase out to a depth of 50mm. Elsewhere the cable will run either through trunking or on the surface. I am a little concerned about carving halfway through the blocks for a 2m vertical run and I am not sure if they are already the hollow type, the ones I have had to sink boxes into elsewhere appear solid but you never know?

It's 50mm from final finished surface not 50 mm into the blocks.


Just to clarify: if the cable(s) are protected by a 30mA, 30ms RCD or RCBO
do they have to be a) protected


The RCD protection alone is adequate. Its only when RCD protection is
not available, that other remedies may become required.

b)as far in a 50mm?


For a non RCD cable, then its needs:

Surface wired (bare or in trunking), or
To be buried = 50mm from the surface, or
Mechanically protected by earthed metal - be it capping, conduit, armour
etc, or
A deviation from the regs based on the specific circumstances.

It seems that surface-mounted mini-trunking would be OK; what if that were
flush with or just below the surface?


If its visible and obviously a cable, then its fine.


Next door had the same problem. He used just steel capping and RCD so that
it's all covered by just the plaster. As in my house, some runs are not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!
--
Peter.
The gods will stay away
whilst religions hold sway
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Default Consumer Units with RCBOs

Just an update. The RCBO plan has been shelved having missed the offer so it is back to RCDs and MCBs. The garage CU will now be a RCD protected unit with MCBs the supply cable will come from an non RCD protected MCB in the main CU this arrangement should mean faults in the garage circuits should not affect the house circuits which was my main concern when considering RCBOs. The garage supply cable will either run down 50mm below the surface for 2m or run on the surface behind a kitchen unit. I got an MK CU with RCD and fully populated for £73, a couple of MCBs need swapping but I can do that when the main CU is replaced as the existing one is an MK.

Thanks for all the help and advice particularly Adam.

Richard
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On 31/05/2019 08:52, PeterC wrote:
On Thu, 30 May 2019 18:22:17 +0100, John Rumm wrote:


Just to clarify: if the cable(s) are protected by a 30mA, 30ms RCD or RCBO
do they have to be a) protected


The RCD protection alone is adequate. Its only when RCD protection is
not available, that other remedies may become required.

b)as far in a 50mm?


For a non RCD cable, then its needs:

Surface wired (bare or in trunking), or
To be buried = 50mm from the surface, or
Mechanically protected by earthed metal - be it capping, conduit, armour
etc, or
A deviation from the regs based on the specific circumstances.

It seems that surface-mounted mini-trunking would be OK; what if that were
flush with or just below the surface?


If its visible and obviously a cable, then its fine.


Next door had the same problem. He used just steel capping and RCD so that


If you have the RCD, then no additional protection is required -
although for cables that are being installed before plastering, capping
is normally a good idea to protect them from damage during plastering.

it's all covered by just the plaster. As in my house, some runs are not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


Cables tend to not be magnetic unless armoured.

The requirements these days specify RCD protection for all sockets -
regardless of how the cables are run.


--
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John.

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On 30/05/2019 18:30, wrote:

I have a house consumer unit in the hallway. A cable runs in a
straight line from the middle of the back of the consumer unit
straight through a double skin wall, then a ceiling - floor void and
then a second double skin wall and then it is surface clipped around
the garage wall to a secondary consumer unit which will be filled
with RCBOs. So from my understanding of this thread I can fit a 45a
MCB in the main consumer unit and connect the secondary consumer unit
to that?


Pretty much.

The cable is currently 6mm2 T&E and is more than 50mm from the
floorboards and plasterboard......


Depending on the installation method, that's borderline for a 45A MCB.

Have a look at the table:

http://wiki.diyfaq.org.uk/index.php/Cables#Cable_Sizes

The max current for 6mm^2 will only be large enough if installed method
C (i.e. clipped direct to a surface, or embedded in masonry).

Your described installation method more closely matches number 47
(BS7671 18th ed, blue book) for the section through the ceiling. That is
described as "Single-core or Multicore cable - in a ceiling void, or in
a suspended floor.", and the reference method listed is B. So that
reduces the capacity of the 6mm^2 to 38A.

While that *might* still be acceptable - depending on what load is going
in the final CU[1]. However in applications like this, it would be much
much better to have overload protection for the submain as well, since
its impossible to predict what might change in the future and you don't
really want to rely on a future installer understanding the restrictions
imposed by a sub optimal submain.

So smaller head end MCB, or bigger cable...


[1] (if the load is less that that so overload of the submain is not
possible, then you can argue that the head end MCB only needs to provide
fault protection for the submain)


--
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John.

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On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so that
it's all covered by just the plaster. As in my house, some runs are not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.


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On Fri, 31 May 2019 11:11:43 +0100, John Rumm wrote:

On 31/05/2019 08:52, PeterC wrote:
On Thu, 30 May 2019 18:22:17 +0100, John Rumm wrote:


Just to clarify: if the cable(s) are protected by a 30mA, 30ms RCD or RCBO
do they have to be a) protected

The RCD protection alone is adequate. Its only when RCD protection is
not available, that other remedies may become required.

b)as far in a 50mm?

For a non RCD cable, then its needs:

Surface wired (bare or in trunking), or
To be buried = 50mm from the surface, or
Mechanically protected by earthed metal - be it capping, conduit, armour
etc, or
A deviation from the regs based on the specific circumstances.

It seems that surface-mounted mini-trunking would be OK; what if that were
flush with or just below the surface?

If its visible and obviously a cable, then its fine.


Next door had the same problem. He used just steel capping and RCD so that


If you have the RCD, then no additional protection is required -
although for cables that are being installed before plastering, capping
is normally a good idea to protect them from damage during plastering.

Good, thank you.

it's all covered by just the plaster. As in my house, some runs are not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


Cables tend to not be magnetic unless armoured.

Agreed - but the steel capping might be :-)

The requirements these days specify RCD protection for all sockets -
regardless of how the cables are run.


At least tht's OK then.
--
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The gods will stay away
whilst religions hold sway
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On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.


Yup, like in the pictures:

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

--
Cheers,

John.

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On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.


Yup, like in the pictures:

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


But some aren't within 150mm of edges.
--
Peter.
The gods will stay away
whilst religions hold sway
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On 01/06/2019 03:24, John Rumm wrote:
On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.


Yup, like in the pictures:


While the picture is clear, I find the regulation anything but when it
comes to zones defined by sockets, switches etc. 522.6.202 has - so far
as relevant -

"Where the cable is connected to a point, accessory or switchgear on any
surface of the wall or partition, the cable may be installed in a zone
either horizontally or vertically, to the point, accessory or
switchgear. Where the location of the accessory, point or switchgear
can be determined from the reverse side, a zone formed on one side of a
wall of 100 mm thickness or less or partition of 100 mm thickness or
less extends to the reverse side"

On a plain reading that seems to mean one can't use the zone defined by
a socket, switch etc to run a cable that's /not/ connected to a socket
etc in the zone but is just "passing through" on the way to another
room, a garage or wherever.


--
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On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.


Yup, like in the pictures:

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


But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.

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On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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


But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.


They are straight but not within 150mm of an edge.
--
Peter.
The gods will stay away
whilst religions hold sway
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Default Consumer Units with RCBOs

On 01/06/2019 13:23, PeterC wrote:
On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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

But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.


They are straight but not within 150mm of an edge.


The wiki article gives the definition of the 3 safe zones. The cables
only need to be in one of them. They may if needed use 2 or all 3 of them.



--
Adam
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On 01/06/2019 13:23, PeterC wrote:
On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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

But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.


They are straight but not within 150mm of an edge.


They don't need to be...

A safe (or in this context a better word might be "expected") zone is
one of three separate and distinct areas:

1) Horizontally or vertically intersecting with the location of a
visible electrical accessory. Hence the position of the zone is not a
fixed place, but is defined by where the accessory actually is. So if
you see a socket you know not to drill directly above, below, or to
either side of it. That socket might be 2m from the nearest corner - but
it still defines a zone around it.

2) At the intersection of two vertical walls - this applies even if
there is no visible accessory. So don't go drilling in the corner beside
a chimney breast even if you can't see a switch or socket.

3) At the intersection between wall and ceiling.


Basically, if installing cables, they need to be in a least one of these
zones. They can be in more than one, but there is no benefit or
requirement for this. Hence avoid running cables at odd angles, or
changing direction of them mid run.




--
Cheers,

John.

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On 01/06/2019 11:12, Terry Casey wrote:
In article ,
says...

On a plain reading that seems to mean one can't use the zone defined by
a socket, switch etc to run a cable that's /not/ connected to a socket
etc in the zone but is just "passing through" on the way to another
room, a garage or wherever.


Surely not. The whole point of the safe zones is to indicate
where it is safe to run the "just passing through" cable
because these zones coul;d equally be designated danger zomnes
when it comes to drilling holes, etc.

Iy you took a different route for the cable avoiding these
zones there is nothing to indicate where the cable runs,
making it particularly vulnerable.


My point was that IMO the regulation doesn't actually say what it is
generally taken to.

I'm happy to be guided to how to be read it so the zones created by an
accessory etc on the wall apply to a cable that is not connected to it.
The only way I can see is to read "the" as "any" so it becomes:

"Where /any/ cable is connected to a point, accessory or switchgear on
any surface of the wall or partition, /any/ cable may be installed in a
zone either horizontally or vertically, to the point, accessory or
switchgear."

But if so, WTF don't they say that in the first place? Reading "the" to
include "any" is not normal. (And still means fitting an accessory with
nothing connected to it does not create safe zones.)
..


--
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reply-to address is (intended to be) valid
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On 01/06/2019 13:23, PeterC wrote:
On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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

But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.


They are straight but not within 150mm of an edge.


I am a very strong advocate of DIY by competent DIYers but sometimes we
all need to recognise when it is best to "get someone in", perhaps this
is a case when that would be wise. Please don't flame me for making the
suggestion.
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On Saturday, 1 June 2019 17:14:10 UTC+1, wrote:

I am a very strong advocate of DIY by competent DIYers but sometimes we
all need to recognise when it is best to "get someone in",


Yes. But that only happens on occasion

perhaps this
is a case when that would be wise. Please don't flame me for making the
suggestion.


I'm firing up the barbie. Seriously, installing cable in walls is not difficult.


NT
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One of the worst areas I see in the home where cables are not in the sage zones is on the kitchen and more specifically for the cooker.

Typically the cable going to the cooker isolation switch is in safe zones.

There is typically a cooker cable junction box in the wall behind the cooker.

Then there is a short run of cable from the cooker isolation switch to the cooker cable junction box and it's always diagonal! I have never seen a vertical and horizontal cable run between the isolation switch and junction box.....
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On Sat, 1 Jun 2019 15:31:40 +0100, John Rumm wrote:

On 01/06/2019 13:23, PeterC wrote:
On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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

But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.


They are straight but not within 150mm of an edge.


They don't need to be...

A safe (or in this context a better word might be "expected") zone is
one of three separate and distinct areas:

1) Horizontally or vertically intersecting with the location of a
visible electrical accessory. Hence the position of the zone is not a
fixed place, but is defined by where the accessory actually is. So if
you see a socket you know not to drill directly above, below, or to
either side of it. That socket might be 2m from the nearest corner - but
it still defines a zone around it.

2) At the intersection of two vertical walls - this applies even if
there is no visible accessory. So don't go drilling in the corner beside
a chimney breast even if you can't see a switch or socket.

3) At the intersection between wall and ceiling.

Basically, if installing cables, they need to be in a least one of these
zones. They can be in more than one, but there is no benefit or
requirement for this. Hence avoid running cables at odd angles, or
changing direction of them mid run.


Thanks, this clarifies it.
There's only one cable that's diagonal and that is clipped to the surface -
and avoided a re-wire.
--
Peter.
The gods will stay away
whilst religions hold sway
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On Sat, 1 Jun 2019 17:14:06 +0100, wrote:

On 01/06/2019 13:23, PeterC wrote:
On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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

But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.


They are straight but not within 150mm of an edge.


I am a very strong advocate of DIY by competent DIYers but sometimes we
all need to recognise when it is best to "get someone in", perhaps this
is a case when that would be wise. Please don't flame me for making the
suggestion.


These were done by the original electricians.
Next door had a shower pump taken from the lighting circuit that is on a
100mA RCD; that was done by a 'qualified' electrician (domestic and
commercial).
--
Peter.
The gods will stay away
whilst religions hold sway
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On 02/06/2019 08:34, PeterC wrote:
On Sat, 1 Jun 2019 17:14:06 +0100, wrote:

On 01/06/2019 13:23, PeterC wrote:
On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and RCD so
that
it's all covered by just the plaster. As in my house, some runs are
not in
Safe Zones - but do go to sockets or switches and are all vertical or
horizontal. Should be easy to detect - a decent magnet would do it!


They are in safe zones then as they extended from switches and sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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

But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.

They are straight but not within 150mm of an edge.


I am a very strong advocate of DIY by competent DIYers but sometimes we
all need to recognise when it is best to "get someone in", perhaps this
is a case when that would be wise. Please don't flame me for making the
suggestion.


These were done by the original electricians.
Next door had a shower pump taken from the lighting circuit that is on a
100mA RCD; that was done by a 'qualified' electrician (domestic and
commercial).


Depending on the circumstances, that may be a sensible design decision.

The use of the 100mA RCD might be because the earthing system is TT and
hence all circuits needed to be RCD protected (even in days before this
was common) to ensure disconnection in the event of an earth fault.

If the pump is in a bathroom, there are quite possibly no other
electrical circuits available near by, and the load from a pump is only
likely to be a few hundred watts - so it will not stretch the supply.
That's the same reason other small loads in bathrooms like extractor
fans or shaver sockets are often fed from a lighting circuit.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
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On Sun, 2 Jun 2019 14:42:19 +0100, John Rumm wrote:

Next door had a shower pump taken from the lighting circuit that is on a
100mA RCD; that was done by a 'qualified' electrician (domestic and
commercial).


Depending on the circumstances, that may be a sensible design decision.

The use of the 100mA RCD might be because the earthing system is TT and
hence all circuits needed to be RCD protected (even in days before this
was common) to ensure disconnection in the event of an earth fault.

It's TN-C-S - updated about 25 years ago.

If the pump is in a bathroom, there are quite possibly no other
electrical circuits available near by, and the load from a pump is only
likely to be a few hundred watts - so it will not stretch the supply.
That's the same reason other small loads in bathrooms like extractor
fans or shaver sockets are often fed from a lighting circuit.


No circuits, but the taps are on copper pipe (mine's all plastic, so no
Earth path) and the bonding's dodgey. My shower is off the 30mA RCD (same
board and basic installation, done at the same time).
Slightly worrying was that the pump was in a housing on the wall, the same
as an electric shower, and the brushes were wearing out resulting in
graphite visible around the joins and control - I don't know how conductive
that would be. Perhaps best not to have the iron bath bonded to earth in
this case.
--
Peter.
The gods will stay away
whilst religions hold sway
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On 02/06/2019 14:42, John Rumm wrote:
On 02/06/2019 08:34, PeterC wrote:
On Sat, 1 Jun 2019 17:14:06 +0100, wrote:

On 01/06/2019 13:23, PeterC wrote:
On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and
RCD so
that
it's all covered by just the plaster. As in my house, some runs
are
not in
Safe Zones - but do go to sockets or switches and are all
vertical or
horizontal. Should be easy to detect - a decent magnet would do
it!


They are in safe zones then as they extended from switches and
sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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

But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.

They are straight but not within 150mm of an edge.


I am a very strong advocate of DIY by competent DIYers but sometimes we
all need to recognise when it is best to "get someone in", perhaps this
is a case when that would be wise. Please don't flame me for making the
suggestion.


These were done by the original electricians.
Next door had a shower pump taken from the lighting circuit that is on a
100mA RCD; that was done by a 'qualified' electrician (domestic and
commercial).


Depending on the circumstances, that may be a sensible design decision.

The use of the 100mA RCD might be because the earthing system is TT and
hence all circuits needed to be RCD protected (even in days before this
was common) to ensure disconnection in the event of an earth fault.

If the pump is in a bathroom, there are quite possibly no other
electrical circuits available near by, and the load from a pump is only
likely to be a few hundred watts - so it will not stretch the supply.
That's the same reason other small loads in bathrooms like extractor
fans or shaver sockets are often fed from a lighting circuit.



Most shower pumps require a 30mA RCD supply.

--
Adam


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On Saturday, 1 June 2019 19:40:05 UTC+1, wrote:
I have never seen a vertical and horizontal cable run between
the isolation switch and junction box.....


Mine is vertical - diagonal - vertical.

Installed by the builders, at least it's in conduit.

And at least since I moved in the conduit is now earthed.

Owain



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The diagonal cooker cables I see behind cookers are invariably under plastic capping... And is a single straight diagonal run.

So well done to the builder for using metal conduit and for you in earthing said conduit.....
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On 02/06/2019 16:02, ARW wrote:
On 02/06/2019 14:42, John Rumm wrote:
On 02/06/2019 08:34, PeterC wrote:
On Sat, 1 Jun 2019 17:14:06 +0100, wrote:

On 01/06/2019 13:23, PeterC wrote:
On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping and
RCD so
that
it's all covered by just the plaster. As in my house, some
runs are
not in
Safe Zones - but do go to sockets or switches and are all
vertical or
horizontal. Should be easy to detect - a decent magnet would
do it!


They are in safe zones then as they extended from switches and
sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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

But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.

They are straight but not within 150mm of an edge.


I am a very strong advocate of DIY by competent DIYers but sometimes we
all need to recognise when it is best to "get someone in", perhaps this
is a case when that would be wise. Please don't flame me for making the
suggestion.

These were done by the original electricians.
Next door had a shower pump taken from the lighting circuit that is on a
100mA RCD; that was done by a 'qualified' electrician (domestic and
commercial).


Depending on the circumstances, that may be a sensible design decision.

The use of the 100mA RCD might be because the earthing system is TT
and hence all circuits needed to be RCD protected (even in days before
this was common) to ensure disconnection in the event of an earth fault.

If the pump is in a bathroom, there are quite possibly no other
electrical circuits available near by, and the load from a pump is
only likely to be a few hundred watts - so it will not stretch the
supply. That's the same reason other small loads in bathrooms like
extractor fans or shaver sockets are often fed from a lighting circuit.



Most shower pumps require a 30mA RCD supply.


These days yup... a historical install may not have specced it.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
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On 02/06/2019 22:20, John Rumm wrote:
On 02/06/2019 16:02, ARW wrote:
On 02/06/2019 14:42, John Rumm wrote:
On 02/06/2019 08:34, PeterC wrote:
On Sat, 1 Jun 2019 17:14:06 +0100, wrote:

On 01/06/2019 13:23, PeterC wrote:
On Sat, 1 Jun 2019 09:15:11 +0100, dennis@home wrote:

On 01/06/2019 08:17, PeterC wrote:
On Sat, 1 Jun 2019 03:24:56 +0100, John Rumm wrote:

On 31/05/2019 15:42, dennis@home wrote:
On 31/05/2019 08:52, PeterC wrote:

Next door had the same problem. He used just steel capping
and RCD so
that
it's all covered by just the plaster. As in my house, some
runs are
not in
Safe Zones - but do go to sockets or switches and are all
vertical or
horizontal. Should be easy to detect - a decent magnet would
do it!


They are in safe zones then as they extended from switches and
sockets
in the vertical and horizontal directions.

Yup, like in the pictures:

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

But some aren't within 150mm of edges.


But you said they were vertical and horizontal not bent.

They are straight but not within 150mm of an edge.


I am a very strong advocate of DIY by competent DIYers but
sometimes we
all need to recognise when it is best to "get someone in", perhaps
this
is a case when that would be wise. Please don't flame me for making
the
suggestion.

These were done by the original electricians.
Next door had a shower pump taken from the lighting circuit that is
on a
100mA RCD; that was done by a 'qualified' electrician (domestic and
commercial).

Depending on the circumstances, that may be a sensible design decision.

The use of the 100mA RCD might be because the earthing system is TT
and hence all circuits needed to be RCD protected (even in days
before this was common) to ensure disconnection in the event of an
earth fault.

If the pump is in a bathroom, there are quite possibly no other
electrical circuits available near by, and the load from a pump is
only likely to be a few hundred watts - so it will not stretch the
supply. That's the same reason other small loads in bathrooms like
extractor fans or shaver sockets are often fed from a lighting circuit.



Most shower pumps require a 30mA RCD supply.


These days yup... a historical install may not have specced it.


And you know my views on using a RCD as protection vs supplementary bonding.





--
Adam


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On 2019-06-03, ARW wrote:

On 02/06/2019 22:20, John Rumm wrote:
On 02/06/2019 16:02, ARW wrote:


Most shower pumps require a 30mA RCD supply.


These days yup... a historical install may not have specced it.


And you know my views on using a RCD as protection vs supplementary bonding.


I don't but I'll bite --- why?
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On 04/06/2019 10:02, Adam Funk wrote:
On 2019-06-03, ARW wrote:

On 02/06/2019 22:20, John Rumm wrote:
On 02/06/2019 16:02, ARW wrote:


Most shower pumps require a 30mA RCD supply.

These days yup... a historical install may not have specced it.


And you know my views on using a RCD as protection vs supplementary bonding.


I don't but I'll bite --- why?


RCDs fail. Supplementary bonding doesn't.

--
Adam
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On 2019-06-04, ARW wrote:

On 04/06/2019 10:02, Adam Funk wrote:
On 2019-06-03, ARW wrote:

On 02/06/2019 22:20, John Rumm wrote:
On 02/06/2019 16:02, ARW wrote:


Most shower pumps require a 30mA RCD supply.

These days yup... a historical install may not have specced it.

And you know my views on using a RCD as protection vs supplementary bonding.


I don't but I'll bite --- why?


RCDs fail. Supplementary bonding doesn't.


Fair point.
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