A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We have
an upstairs ring main, downstairs ring main and a kitchen ring main, all of
which are protected by the RCD, and the problem is the kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD trips
(plugging the same things into either upstairs or downstairs rings does
*not* trip it).

Splitting the ring at the CU and using a proper Megger (500v insulation
resistance tester, not just a multimeter) to test each leg of the ring shows
the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " " "
"
N-E = " " " " " "
"

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

TIA,

Mogweed

Mogweed wrote:
A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We
have an upstairs ring main, downstairs ring main and a kitchen ring
main, all of which are protected by the RCD, and the problem is the
kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD
trips (plugging the same things into either upstairs or downstairs
rings does *not* trip it).

Splitting the ring at the CU and using a proper Megger (500v
insulation resistance tester, not just a multimeter) to test each leg
of the ring shows the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " "
" "
N-E = " " " " "
" "

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

TIA,

Mogweed

Are you 100% sure you don't have a short?

Have you been capping back the cable into chases, Screwed down floor
boards?
--
Sir Benjamin Middlethwaite

Mogweed wrote:

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

Have you checked for a misplaced neutral?
'Tis a common mistake on a split load CU...

Lee

--
Email address is valid, but is unlikely to be read.

"The3rd Earl Of Derby" wrote in message
k...
Mogweed wrote:
A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We
have an upstairs ring main, downstairs ring main and a kitchen ring
main, all of which are protected by the RCD, and the problem is the
kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD
trips (plugging the same things into either upstairs or downstairs
rings does *not* trip it).

Splitting the ring at the CU and using a proper Megger (500v
insulation resistance tester, not just a multimeter) to test each leg
of the ring shows the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " "
" "
N-E = " " " " "
" "

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

TIA,

Mogweed

Are you 100% sure you don't have a short?

Have you been capping back the cable into chases, Screwed down floor
boards?
--
Sir Benjamin Middlethwaite


You have to believe your instruments so I can only go on what the megger
tells me, and that says that there is no short - tried shorting the test
leads and the meter swings right over to 0 ohms so the megger seems to be
working OK. Cables capped - and chases plastered over ( Some
floorboards screwed back down - but megger shows no shorts.

Mogweed.

Mogweed wrote:
"The3rd Earl Of Derby" wrote in message
k...
Mogweed wrote:
A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit.
We have an upstairs ring main, downstairs ring main and a kitchen
ring main, all of which are protected by the RCD, and the problem
is the kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill
or whatever) is plugged into *any* socket on the kitchen ring, the
RCD trips (plugging the same things into either upstairs or
downstairs rings does *not* trip it).

Splitting the ring at the CU and using a proper Megger (500v
insulation resistance tester, not just a multimeter) to test each
leg of the ring shows the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " "
" "
N-E = " " " " "
" "

so no short-circuits, but yet the RCD trips. What's the problem -
more importantly, what's the solution to the problem? )

TIA,

Mogweed

Are you 100% sure you don't have a short?

Have you been capping back the cable into chases, Screwed down floor
boards?
--
Sir Benjamin Middlethwaite


You have to believe your instruments so I can only go on what the
megger tells me, and that says that there is no short - tried
shorting the test leads and the meter swings right over to 0 ohms so
the megger seems to be working OK. Cables capped - and chases
plastered over ( Some floorboards screwed back down - but
megger shows no shorts.

Mogweed.

Take the kitchen strap out of the CU attach a battery&bulb L to +, - to
bulb and bulb to N and see if the bulb lights? do this on the E to L and E
to N.
If it lights you have a short if not then start looking at CU

--
Sir Benjamin Middlethwaite

"The3rd Earl Of Derby" wrote in message
k...
Mogweed wrote:
"The3rd Earl Of Derby" wrote in message
k...
Mogweed wrote:

Are you 100% sure you don't have a short?

Have you been capping back the cable into chases, Screwed down floor
boards?
--
Sir Benjamin Middlethwaite


You have to believe your instruments so I can only go on what the
megger tells me, and that says that there is no short - tried
shorting the test leads and the meter swings right over to 0 ohms so
the megger seems to be working OK. Cables capped - and chases
plastered over ( Some floorboards screwed back down - but
megger shows no shorts.

Mogweed.

Take the kitchen strap out of the CU attach a battery&bulb L to +, - to
bulb and bulb to N and see if the bulb lights? do this on the E to L and E
to N.
If it lights you have a short if not then start looking at CU

--
Sir Benjamin Middlethwaite


Cheers Sir Benjamin, I'll give it a go.

Mogweed.

On Fri, 11 Nov 2005 18:58:17 GMT, Lee
wrote:

Mogweed wrote:

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

Have you checked for a misplaced neutral?
'Tis a common mistake on a split load CU...

That does sound like the problem - possibly a neutral swapped with an
earth, otherwise the RCD wouldn't trip with a non-earthed item such as
a radio.

--
Frank Erskine

"Lee" wrote in message
...
Mogweed wrote:

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

Have you checked for a misplaced neutral?
'Tis a common mistake on a split load CU...

Lee

Ah, now then, I haven't checked for that - mainly because I didn't know that
a neutral could be misplaced. They all go to a common bar don't they?

Mogweed.

In article , says...
A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We have
an upstairs ring main, downstairs ring main and a kitchen ring main, all of
which are protected by the RCD, and the problem is the kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD trips
(plugging the same things into either upstairs or downstairs rings does
*not* trip it).

Splitting the ring at the CU and using a proper Megger (500v insulation
resistance tester, not just a multimeter) to test each leg of the ring shows
the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " " "
"
N-E = " " " " " "
"

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

TIA,

Mogweed




As a portable radio, which presumably is double insulated, is also
tripping it, it suggests that the fault is not on the earth, so I would
guess that there is either a neutral leg or a live leg connected to the
wrong side of the RCD.

Alternatively, if it is a Wylex S/L board, there have been quite a few
faulty RCDs coming from them of late - at least in our neck of the woods.
Doesn't explain why it is only one ring which causes the problem though.
I'd check first that the ring is terminated (both conductors, both legs)
on the correct side of the RCD first.

On Fri, 11 Nov 2005 18:36:00 -0000, "Mogweed"
wrote:

A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We have
an upstairs ring main, downstairs ring main and a kitchen ring main, all of
which are protected by the RCD, and the problem is the kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD trips
(plugging the same things into either upstairs or downstairs rings does
*not* trip it).

Splitting the ring at the CU and using a proper Megger (500v insulation
resistance tester, not just a multimeter) to test each leg of the ring shows
the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " " "
"
N-E = " " " " " "
"

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

TIA,

Mogweed

Faulty RCD? If they are the same value try swapping two and see if the
fault moves.

sponix

In message , Frank Erskine
writes
On Fri, 11 Nov 2005 18:58:17 GMT, Lee
wrote:

Mogweed wrote:

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

Have you checked for a misplaced neutral?
'Tis a common mistake on a split load CU...

That does sound like the problem - possibly a neutral swapped with an
earth, otherwise the RCD wouldn't trip with a non-earthed item such as
a radio.

Yes it would, if the kitchen ring neutral has been returned to the
non-RCD busbar. A common and easy to make mistake.

--
steve

"Gary Cavie" wrote in message
t...
In article , says...
A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We
have
an upstairs ring main, downstairs ring main and a kitchen ring main, all
of
which are protected by the RCD, and the problem is the kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD trips
(plugging the same things into either upstairs or downstairs rings does
*not* trip it).

Splitting the ring at the CU and using a proper Megger (500v insulation
resistance tester, not just a multimeter) to test each leg of the ring
shows
the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " "
"
"
N-E = " " " " "
"
"

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

TIA,

Mogweed




As a portable radio, which presumably is double insulated, is also
tripping it, it suggests that the fault is not on the earth, so I would
guess that there is either a neutral leg or a live leg connected to the
wrong side of the RCD.

Alternatively, if it is a Wylex S/L board, there have been quite a few
faulty RCDs coming from them of late - at least in our neck of the woods.
Doesn't explain why it is only one ring which causes the problem though.
I'd check first that the ring is terminated (both conductors, both legs)
on the correct side of the RCD first.

Thanks Gary, I'll check that - and it is actually a Wylex CU but as you say,
if it was a faulty RCD it should show up on the other rings too.

Mogweed.

"--s-p-o-n-i-x--" wrote in message
...
On Fri, 11 Nov 2005 18:36:00 -0000, "Mogweed"
wrote:

A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We have
an upstairs ring main, downstairs ring main and a kitchen ring main, all
of
which are protected by the RCD, and the problem is the kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD trips
(plugging the same things into either upstairs or downstairs rings does
*not* trip it).

Splitting the ring at the CU and using a proper Megger (500v insulation
resistance tester, not just a multimeter) to test each leg of the ring
shows
the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " "
"
"
N-E = " " " " "
"
"

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

TIA,

Mogweed

Faulty RCD? If they are the same value try swapping two and see if the
fault moves.

sponix

Thanks sponix but I think you're thinking of the MCBs rather than the RCD
)

Mogweed.

Mogweed was thinking very hard :
A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We have an
upstairs ring main, downstairs ring main and a kitchen ring main, all of
which are protected by the RCD, and the problem is the kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD trips
(plugging the same things into either upstairs or downstairs rings does *not*
trip it).

Splitting the ring at the CU and using a proper Megger (500v insulation
resistance tester, not just a multimeter) to test each leg of the ring shows
the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " " " "
N-E = " " " " " " "

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

It sounds as if you/he have managed to mix up the ring circuits, such
that - one of the circuits protected by RCD is mixed up with one not on
the RCD. Thus causing an unbalanced load on the RCD, hence it tripping.

Try disconnecting each pair of 2.5mm in turn and make sure you have
continuity between each pair of both reds and blacks.


--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Fri, 11 Nov 2005 19:58:08 GMT, "Harry Bloomfield"
wrote:


Try disconnecting each pair of 2.5mm in turn and make sure you have
continuity between each pair of both reds and blacks.

Or even browns and blues :-)

--
Frank Erskine

On Fri, 11 Nov 2005 19:44:28 -0000, "Mogweed"
wrote:

Faulty RCD? If they are the same value try swapping two and see if the
fault moves.

sponix

Thanks sponix but I think you're thinking of the MCBs rather than the RCD
)

Well, I have had plug in RCDs that trip when loaded with non-earthed
appliances..

sponix

On or around Fri, 11 Nov 2005 19:27:25 +0000, --s-p-o-n-i-x--
mused:

Faulty RCD? If they are the same value try swapping two and see if the
fault moves.

A split load board installed by a mate with 2 identical RCD's in?
Stick to whatever it is you do normally.
--
| Stuart @ SJW Electrical. Please Reply to group. |

On or around Fri, 11 Nov 2005 19:21:12 -0000, "Mogweed"
mused:


"Lee" wrote in message
...
Mogweed wrote:

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

Have you checked for a misplaced neutral?
'Tis a common mistake on a split load CU...

Lee

Ah, now then, I haven't checked for that - mainly because I didn't know that
a neutral could be misplaced. They all go to a common bar don't they?

Nope, seperate neutral bars for RCD and non-RCD circuits. Did the
circuit ever work? If it did, then the misplaced neutral idea is wrong
as that would trip the RCD from day one.
--
| Stuart @ SJW Electrical. Please Reply to group. |

On Fri, 11 Nov 2005 20:19:52 +0000, Lurch
wrote:

On or around Fri, 11 Nov 2005 19:27:25 +0000, --s-p-o-n-i-x--
mused:

Faulty RCD? If they are the same value try swapping two and see if the
fault moves.

A split load board installed by a mate with 2 identical RCD's in?
Stick to whatever it is you do normally.

So you are saying one RCD protects the whole house? That's a pretty
stupid idea in addition to the fact it contravenes 16th edition
regulations.

sponix

Frank Erskine has brought this to us :
On Fri, 11 Nov 2005 19:58:08 GMT, "Harry Bloomfield"
wrote:


Try disconnecting each pair of 2.5mm in turn and make sure you have
continuity between each pair of both reds and blacks.

Or even browns and blues :-)

Not if he is trying to circumvent 'Part P' :-)

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On or around Fri, 11 Nov 2005 20:37:35 +0000, --s-p-o-n-i-x--
mused:

On Fri, 11 Nov 2005 20:19:52 +0000, Lurch
wrote:

On or around Fri, 11 Nov 2005 19:27:25 +0000, --s-p-o-n-i-x--
mused:

Faulty RCD? If they are the same value try swapping two and see if the
fault moves.

A split load board installed by a mate with 2 identical RCD's in?
Stick to whatever it is you do normally.

So you are saying one RCD protects the whole house? That's a pretty
stupid idea in addition to the fact it contravenes 16th edition
regulations.

Dr Dimwit?

It doesn't contravene BS7671, under certain circumstances, and a
standard slit load board has one RCD covering *some* circuits, not
all. I suggest you read up on plit load boards before talking more
********.
--
| Stuart @ SJW Electrical. Please Reply to group. |

Harry Bloomfield wrote:
Frank Erskine has brought this to us :
On Fri, 11 Nov 2005 19:58:08 GMT, "Harry Bloomfield"
wrote:


Try disconnecting each pair of 2.5mm in turn and make sure you have
continuity between each pair of both reds and blacks.

Or even browns and blues :-)

Not if he is trying to circumvent 'Part P' :-)

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Not necessarily - brown and blue cable was on sale before Part P was in
force.

CRB

Lurch wrote:
On or around Fri, 11 Nov 2005 20:37:35 +0000, --s-p-o-n-i-x--
mused:

So you are saying one RCD protects the whole house? That's a pretty
stupid idea in addition to the fact it contravenes 16th edition
regulations.

It doesn't contravene BS7671, under certain circumstances, and a
standard slit load board has one RCD covering *some* circuits, not
all. I suggest you read up on plit load boards before talking more
********.

I've seen plenty of non-split-load CU's for sale complete with RCDs at
the likes of Screwfix (eg http://tinyurl.com/bb2ej); I understand it's
not a good idea to have all circuits protected by an RCD, but when/why
would it be actually against regs to fit one of these as a whole-house CU?

David

"Lobster" wrote in message...
I've seen plenty of non-split-load CU's for sale complete with RCDs at the
likes of Screwfix (eg http://tinyurl.com/bb2ej); I understand it's not a
good idea to have all circuits protected by an RCD, but when/why would it
be actually against regs to fit one of these as a whole-house CU?

I don't know about being "against the regs" but certain items, such as
immersion heaters, can cause "nuisence trips" even though there's nothing
wrong with them. That's why they should be connected to a non-rcd fed
source.


--
Best Wishes
Simon (aka Dark Angel)
"Dark Angel's Realm of Horror" - http://www.realmofhorror.co.uk
"Realm of Horror Radio" - http://www.live365.com/stations/313834

"Mogweed" wrote in message
...
A mate of mine has completely rewired our house so everything in the
installation is brand new, including the split-load consumer unit. We have
an upstairs ring main, downstairs ring main and a kitchen ring main, all of
which are protected by the RCD, and the problem is the kitchen ring.

As soon as *anything* (portable radio, halogen lamp, electric drill or
whatever) is plugged into *any* socket on the kitchen ring, the RCD trips
(plugging the same things into either upstairs or downstairs rings does
*not* trip it).

Splitting the ring at the CU and using a proper Megger (500v insulation
resistance tester, not just a multimeter) to test each leg of the ring
shows the following:

L-N = almost infinity resistance (certainly over 1,000Mohms anyway)
L-E = " " " " "
" "
N-E = " " " " "
" "

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )


He has somehow managed to get one or more neutrals wire to the "wrong"
neutral bar in the Consumer Unit. This has been covered many times before so
google is your friend

"Lurch" wrote in message
...
On or around Fri, 11 Nov 2005 19:21:12 -0000, "Mogweed"
mused:


"Lee" wrote in message
...
Mogweed wrote:

so no short-circuits, but yet the RCD trips. What's the problem - more
importantly, what's the solution to the problem? )

Have you checked for a misplaced neutral?
'Tis a common mistake on a split load CU...

Lee

Ah, now then, I haven't checked for that - mainly because I didn't know
that
a neutral could be misplaced. They all go to a common bar don't they?

Nope, seperate neutral bars for RCD and non-RCD circuits. Did the
circuit ever work? If it did, then the misplaced neutral idea is wrong
as that would trip the RCD from day one.

I read this as all the time since rewiring

On or around Sat, 12 Nov 2005 10:17:36 GMT, Lobster
mused:

Lurch wrote:
On or around Fri, 11 Nov 2005 20:37:35 +0000, --s-p-o-n-i-x--
mused:

So you are saying one RCD protects the whole house? That's a pretty
stupid idea in addition to the fact it contravenes 16th edition
regulations.

It doesn't contravene BS7671, under certain circumstances, and a
standard slit load board has one RCD covering *some* circuits, not
all. I suggest you read up on plit load boards before talking more
********.

I've seen plenty of non-split-load CU's for sale complete with RCDs at
the likes of Screwfix (eg http://tinyurl.com/bb2ej);

It's not the board itself that's against the regs, it's the
application. I've got 2 boards here with front end RCD's, I've also
got 2 with main switch incomers.
--
| Stuart @ SJW Electrical. Please Reply to group. |

Because the Regs require circuits to be separated so that a fault on one
does not result in disconnection of others (etc). I've quoted what I think
are the Regs being broken before.


Given that interpretation then any board with two or more circuits on one
RCD would fail to comply with regs. Surely this is a requirement only for
overcurrent?
fx- scurries away to consult his regs book

In article , Dark
Angel writes

"Lobster" wrote in message...
I've seen plenty of non-split-load CU's for sale complete with RCDs at the
likes of Screwfix (eg http://tinyurl.com/bb2ej); I understand it's not a
good idea to have all circuits protected by an RCD, but when/why would it
be actually against regs to fit one of these as a whole-house CU?

I don't know about being "against the regs" but certain items, such as
immersion heaters, can cause "nuisence trips" even though there's nothing
wrong with them. That's why they should be connected to a non-rcd fed
source.


If theres nothing wrong with them, then they won't cause an RCD trip.
When they do cause RCD trips then there is something starting to go
wrong with them!.....
--
Tony Sayer

On Sat, 12 Nov 2005 10:17:36 GMT, Lobster
wrote:

I've seen plenty of non-split-load CU's for sale complete with RCDs at
the likes of Screwfix (eg http://tinyurl.com/bb2ej); I understand it's
not a good idea to have all circuits protected by an RCD, but when/why
would it be actually against regs to fit one of these as a whole-house CU?

16th ed regs say that not all circuits must go through a sinle RCD.
Presumably it's so that if you have a major electical failure or fire
the lights stay on..

sponix

"--s-p-o-n-i-x--" wrote in message
...
On Sat, 12 Nov 2005 10:17:36 GMT, Lobster
wrote:

I've seen plenty of non-split-load CU's for sale complete with RCDs at
the likes of Screwfix (eg http://tinyurl.com/bb2ej); I understand it's
not a good idea to have all circuits protected by an RCD, but when/why
would it be actually against regs to fit one of these as a whole-house CU?

16th ed regs say that not all circuits must go through a sinle RCD.
Presumably it's so that if you have a major electical failure or fire
the lights stay on..

sponix

Don't think it does. Which reg says that then?

Bob Watkinson wrote:

Don't think it does.

No, not explicitly, but...

Which reg says that then?

.... 314-01-01 & 314-01-02 when read in conjunction with the guidance to
their interpretation given in the On-Site Guide.

--
Andy

Lurch wrote:

and a
standard slit load board has one RCD covering *some* circuits, not
all. I suggest you read up on plit load boards before talking more
********.

Might be worth adding that you will need RCD protection for *all*
circuits if you have TT earthing.


--
Cheers,

John.

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

On or around Sat, 12 Nov 2005 21:10:45 +0000, John Rumm
mused:

Lurch wrote:

and a
standard slit load board has one RCD covering *some* circuits, not
all. I suggest you read up on plit load boards before talking more
********.

Might be worth adding that you will need RCD protection for *all*
circuits if you have TT earthing.

But I stil wouldn't fit a front end RCD board for a TT. I see what
you're getting at though.
--
| Stuart @ SJW Electrical. Please Reply to group. |

Lurch wrote:

But I stil wouldn't fit a front end RCD board for a TT. I see what
you're getting at though.

I get the impression that a time delay RCD in the incomer position and a
standard RCD mid way down is a pretty standard layout in these cases.


--
Cheers,

John.

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

The3rd Earl Of Derby wrote:
Take the kitchen strap out of the CU attach a battery&bulb L to +, - to
bulb and bulb to N and see if the bulb lights? do this on the E to L and E
to N.
If it lights you have a short if not then start looking at CU

Why would using a battery and bulb be a better tester than a proper
instrument?

alex

"Andy Wade" wrote in message
...
Bob Watkinson wrote:

Don't think it does.

No, not explicitly, but...

Which reg says that then?

... 314-01-01 & 314-01-02 when read in conjunction with the guidance to
their interpretation given in the On-Site Guide.

--
Andy

314-01-01 states that 'Every installation shall be divided into circuits as
necessary to

1) avoid danger in the event of a fault, and
2)facilitate safe operation, inspection, testing and maintenance.

The On Site Guide does not give specific reference to RCD's and this reg
either and indeed the subject has regularly come up for debate on other
forums.
What you have to consider is each installation and what is needed to
comply with the regs. For example in a large multifloor Victorian house
there would be considerable risk of a person falling down the stairs if
because of a fault on another circuit the RCD tripped. On the other hand in
a small ground floor office it is difficult to imagine how danger could be
caused by an RCD trip. In any case if emergency lighting were used the
problem again disappears. In short, the use in itself of a single RCD does
not necessarily breach 314-01-01.
My view is that 314-01-01 is primarily aimed at considerations for
overcurrent protection

314-01-02 requires that other circuits remain energised when a circuit is
faulty. Again, I interpret this as for overcurrent protection. If you
interpret it as being for earth faults then you would not even be able to
use a split board, unless there were a separate rcd for each protected
circuit

Bob Watkinson wrote:

314-01-01 states that 'Every installation shall be divided into circuits as
necessary to

1) avoid danger in the event of a fault, and
2)facilitate safe operation, inspection, testing and maintenance.

The On Site Guide does not give specific reference to RCD's and this reg
either and indeed the subject has regularly come up for debate on other
forums.

Section 3.6.2 gives advice on the application of RCDs and cites
314-01-01 & -02. That seems to me to be fairly "specific."

What you have to consider is each installation and what is needed to
comply with the regs. For example in a large multifloor Victorian house
there would be considerable risk of a person falling down the stairs if
because of a fault on another circuit the RCD tripped. On the other hand in
a small ground floor office it is difficult to imagine how danger could be
caused by an RCD trip. In any case if emergency lighting were used the
problem again disappears. In short, the use in itself of a single RCD does
not necessarily breach 314-01-01.

True, but it does not necessarily comply either.

My view is that 314-01-01 is primarily aimed at considerations for
overcurrent protection

It doesn't actually say that, though.

314-01-02 requires that other circuits remain energised when a circuit is
faulty. Again, I interpret this as for overcurrent protection. If you
interpret it as being for earth faults then you would not even be able to
use a split board, unless there were a separate rcd for each protected
circuit

"Circuit" doesn't necessarily mean "final circuit" (see definitions).
The arrangements feeding the supply to (say) the two halves of a
split-load CU are "circuits" so far as this reg. is concerned. The key
words in 314-01-02 are in the final sentence "... and due account shall
be taken of the consequences of operation of any single protective device."

--
Andy

"Andy Wade" wrote in message
...
Bob Watkinson wrote:

314-01-01 states that 'Every installation shall be divided into circuits
as necessary to

1) avoid danger in the event of a fault, and
2)facilitate safe operation, inspection, testing and maintenance.

The On Site Guide does not give specific reference to RCD's and this
reg either and indeed the subject has regularly come up for debate on
other forums.

Section 3.6.2 gives advice on the application of RCDs and cites 314-01-01
& -02. That seems to me to be fairly "specific."

erm, no I've just re read 3.6.2 and it doesn't mention 314-01-01 or 02.
Although I accept your version may be newer



What you have to consider is each installation and what is needed to
comply with the regs. For example in a large multifloor Victorian house
there would be considerable risk of a person falling down the stairs if
because of a fault on another circuit the RCD tripped. On the other hand
in a small ground floor office it is difficult to imagine how danger
could be caused by an RCD trip. In any case if emergency lighting were
used the problem again disappears. In short, the use in itself of a
single RCD does not necessarily breach 314-01-01.

True, but it does not necessarily comply either.

correct. It all depends on the application


My view is that 314-01-01 is primarily aimed at considerations for
overcurrent protection

It doesn't actually say that, though.

correct again. Though it is stio my view or interpretation if you like.


314-01-02 requires that other circuits remain energised when a circuit is
faulty. Again, I interpret this as for overcurrent protection. If you
interpret it as being for earth faults then you would not even be able to
use a split board, unless there were a separate rcd for each protected
circuit

"Circuit" doesn't necessarily mean "final circuit" (see definitions). The
arrangements feeding the supply to (say) the two halves of a split-load CU
are "circuits" so far as this reg. is concerned. The key words in
314-01-02 are in the final sentence "... and due account shall be taken of
the consequences of operation of any single protective device."

A sentance which like this whole issue is open to interpretation


Andy

Bob Watkinson wrote:

erm, no I've just re read 3.6.2 and it doesn't mention 314-01-01 or 02.
Although I accept your version may be newer

I suspect yours is ancient. I have every edition back to the original
red one (1992). Mention of 314-01-01 first appeared in the green
edition (1995) and of 314-01-02 in the blue one (2002) - the latter
being the one that introduced us to the term the term "shower cubical"
(sic)! We are now on the brown (2004) edition which still has cubical
showers.

I agree with everything else you say.

--
Andy