Hi all.

New member here.

I am a qualified, registered electrician and I have a mojor problem with a new installation and rewiring.

I have rewired 6 new flats and fitted brand new cu's (B&Q £55 ones.. at customer choice!).

Anyway, all rewire and fitting of consumer units of 5 flats are fine... however, the last one... did the rewire, fitted the cu, proceeded to test and the rcd for the kitchen/bathroom is tripping, even though none of the switches are on for the mcb's in the kitchen load of the cu.

The kitchen load comprises of, 3 double sockets, 1 radiator switched spur (RM with sockets), 1 cooker switch and a bathroom wall heater (RM with sockets).

When I remove the earths from the kitchen/bathroom RM, the RCD will stay on, but as soon as I touch either of the RM earth to the earth busbar, it will trip the RCD. Also, I can leave the RM earths in and remove the Neutral RM cables and it will be fine...but as soon as I touch the RM neutral to the busbar, it trips. All connections are fine... to the correct busbars, etc.

I am miffed on this one, and any help would be greatl;y appreciated!

Thanks.

reeveer wrote:


Hi all.

New member here.

I am a qualified, registered electrician and I have a mojor problem with
a new installation and rewiring.

I have rewired 6 new flats and fitted brand new cu's (B&Q �55 ones.. at
customer choice!).

Anyway, all rewire and fitting of consumer units of 5 flats are fine...
however, the last one... did the rewire, fitted the cu, proceeded to
test and the rcd for the kitchen/bathroom is tripping, even though none
of the switches are on for the mcb's in the kitchen load of the cu.

The kitchen load comprises of, 3 double sockets, 1 radiator switched
spur (RM with sockets), 1 cooker switch and a bathroom wall heater (RM
with sockets).

When I remove the earths from the kitchen/bathroom RM, the RCD will stay
on, but as soon as I touch either of the RM earth to the earth busbar,
it will trip the RCD. Also, I can leave the RM earths in and remove the
Neutral RM cables and it will be fine...but as soon as I touch the RM
neutral to the busbar, it trips. All connections are fine... to the
correct busbars, etc.

I am miffed on this one, and any help would be greatl;y appreciated!

Thanks.

Were the IR tests in spec when you tested the circuit?

Did the RCD test as being in normal parameters in particular did it hold in
on the x1 test?

What happens if you disconnect the fixed appliances?


--
Tim Watts

In message , Tim Watts
writes
reeveer wrote:


Hi all.

New member here.

I am a qualified, registered electrician and I have a mojor problem with
a new installation and rewiring.

I have rewired 6 new flats and fitted brand new cu's (B&Q 0 customer choice!).

Anyway, all rewire and fitting of consumer units of 5 flats are fine...
however, the last one... did the rewire, fitted the cu, proceeded to
test and the rcd for the kitchen/bathroom is tripping, even though none
of the switches are on for the mcb's in the kitchen load of the cu.

The kitchen load comprises of, 3 double sockets, 1 radiator switched
spur (RM with sockets), 1 cooker switch and a bathroom wall heater (RM
with sockets).

When I remove the earths from the kitchen/bathroom RM, the RCD will stay
on, but as soon as I touch either of the RM earth to the earth busbar,
it will trip the RCD. Also, I can leave the RM earths in and remove the
Neutral RM cables and it will be fine...but as soon as I touch the RM
neutral to the busbar, it trips. All connections are fine... to the
correct busbars, etc.

I am miffed on this one, and any help would be greatl;y appreciated!

Thanks.

Were the IR tests in spec when you tested the circuit?

Did the RCD test as being in normal parameters in particular did it hold in
on the x1 test?

What happens if you disconnect the fixed appliances?


Could it be that one of the appliances has the neutral linked to its
earth?
--
hugh

On Fri, 21 Sep 2012 22:02:09 +0100, hugh wrote:

I am a qualified, registered electrician ....

But doesn't understand that a N-E short will trip and RCD. Oh and on that
parasitic diybanter "forum".

Could it be that one of the appliances has the neutral linked to its
earth?

Or chippie has stuck a nail through a cable.

--
Cheers
Dave.

In article ,
reeveer wrote:
When I remove the earths from the kitchen/bathroom RM, the RCD will stay
on, but as soon as I touch either of the RM earth to the earth busbar,
it will trip the RCD. Also, I can leave the RM earths in and remove the
Neutral RM cables and it will be fine...but as soon as I touch the RM
neutral to the busbar, it trips. All connections are fine... to the
correct busbars, etc.

I'd guess at an earth to neutral short somewhere.

I'd disconnect a socket somewhere in the middle of the ring including the
wiring, and disconnect one earth at the CU in turn. That should isolate
which half of the ring is the problem. Then go through the sockets in that
half one by one.

--
*He who laughs last, thinks slowest.

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 21 Sep 2012 19:56:59 +0000, reeveer
wrote:


Hi all.

New member here.

I am a qualified, registered electrician and I have a mojor problem with
a new installation and rewiring.

I have rewired 6 new flats and fitted brand new cu's (B&Q £55 ones.. at
customer choice!).

Anyway, all rewire and fitting of consumer units of 5 flats are fine...
however, the last one... did the rewire, fitted the cu, proceeded to
test and the rcd for the kitchen/bathroom is tripping, even though none
of the switches are on for the mcb's in the kitchen load of the cu.

The kitchen load comprises of, 3 double sockets, 1 radiator switched
spur (RM with sockets), 1 cooker switch and a bathroom wall heater (RM
with sockets).

When I remove the earths from the kitchen/bathroom RM, the RCD will stay
on, but as soon as I touch either of the RM earth to the earth busbar,
it will trip the RCD. Also, I can leave the RM earths in and remove the
Neutral RM cables and it will be fine...but as soon as I touch the RM
neutral to the busbar, it trips. All connections are fine... to the
correct busbars, etc.

I am miffed on this one, and any help would be greatl;y appreciated!

Thanks.


What's wrong with those cheap BG CUs from B&Q? I'm tempted to replace
the CU here with one.

--
Graham.
%Profound_observation%

reeveer wrote:
Hi all.

New member here.

I am a qualified, registered electrician and I have a mojor problem with
a new installation and rewiring.

I have rewired 6 new flats and fitted brand new cu's (B&Q £55 ones.. at
customer choice!).

Anyway, all rewire and fitting of consumer units of 5 flats are fine...
however, the last one... did the rewire, fitted the cu, proceeded to
test and the rcd for the kitchen/bathroom is tripping, even though none
of the switches are on for the mcb's in the kitchen load of the cu.

The kitchen load comprises of, 3 double sockets, 1 radiator switched
spur (RM with sockets), 1 cooker switch and a bathroom wall heater (RM
with sockets).

When I remove the earths from the kitchen/bathroom RM, the RCD will stay
on, but as soon as I touch either of the RM earth to the earth busbar,
it will trip the RCD. Also, I can leave the RM earths in and remove the
Neutral RM cables and it will be fine...but as soon as I touch the RM
neutral to the busbar, it trips. All connections are fine... to the
correct busbars, etc.

I am miffed on this one, and any help would be greatl;y appreciated!

Thanks.




earth neutral short somewhere


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

Graham. wrote:
On Fri, 21 Sep 2012 19:56:59 +0000, reeveer
wrote:


Hi all.

New member here.

I am a qualified, registered electrician and I have a mojor problem
with a new installation and rewiring.

I have rewired 6 new flats and fitted brand new cu's (B&Q £55
ones.. at customer choice!).

Anyway, all rewire and fitting of consumer units of 5 flats are
fine... however, the last one... did the rewire, fitted the cu,
proceeded to test and the rcd for the kitchen/bathroom is tripping,
even though none of the switches are on for the mcb's in the
kitchen load of the cu.

The kitchen load comprises of, 3 double sockets, 1 radiator switched
spur (RM with sockets), 1 cooker switch and a bathroom wall heater
(RM with sockets).

When I remove the earths from the kitchen/bathroom RM, the RCD will
stay on, but as soon as I touch either of the RM earth to the earth
busbar, it will trip the RCD. Also, I can leave the RM earths in
and remove the Neutral RM cables and it will be fine...but as soon
as I touch the RM neutral to the busbar, it trips. All connections
are fine... to the correct busbars, etc.

I am miffed on this one, and any help would be greatl;y appreciated!

Thanks.


What's wrong with those cheap BG CUs from B&Q? I'm tempted to replace
the CU here with one.

There is nothing wrong with them at all. I often fit them - well not from
B&Q but from my wholesalers (I pay £54 and I get to choose the MCBs I want.)

They are sturdy, hi-integrity and the RCBOs are only £20 a go (at Screwfix).

Screwfix are doing a 13 way with 10 MCBs for £59.99 if you need a larger
unit.



--
Adam

Owain wrote:
On Sep 21, 9:03 pm, reeveer wrote:
I am a qualified, registered electrician

So you did follow recommended testing procedure and test for
insulation resistance etc before energising the installation?

Because failure to do so would be a breach of the Electricity At Work
Regulations.

You don't need to worry about that if there is RCD protection:-)

--
Adam

On Friday, September 21, 2012 9:03:02 PM UTC+1, reeveer wrote:
Hi all.



New member here.



I am a qualified, registered electrician and I have a mojor problem with

a new installation and rewiring.



I have rewired 6 new flats and fitted brand new cu's (B&Q £55 ones.. at

customer choice!).



Anyway, all rewire and fitting of consumer units of 5 flats are fine...

however, the last one... did the rewire, fitted the cu, proceeded to

test and the rcd for the kitchen/bathroom is tripping, even though none

of the switches are on for the mcb's in the kitchen load of the cu.



The kitchen load comprises of, 3 double sockets, 1 radiator switched

spur (RM with sockets), 1 cooker switch and a bathroom wall heater (RM

with sockets).



When I remove the earths from the kitchen/bathroom RM, the RCD will stay

on, but as soon as I touch either of the RM earth to the earth busbar,

it will trip the RCD. Also, I can leave the RM earths in and remove the

Neutral RM cables and it will be fine...but as soon as I touch the RM

neutral to the busbar, it trips. All connections are fine... to the

correct busbars, etc.



I am miffed on this one, and any help would be greatl;y appreciated!



Thanks.









--

reeveer

On Friday, September 21, 2012 9:03:02 PM UTC+1, reeveer wrote:
Hi all.



New member here.



I am a qualified, registered electrician and I have a mojor problem with

a new installation and rewiring.



I have rewired 6 new flats and fitted brand new cu's (B&Q £55 ones.. at

customer choice!).



Anyway, all rewire and fitting of consumer units of 5 flats are fine...

however, the last one... did the rewire, fitted the cu, proceeded to

test and the rcd for the kitchen/bathroom is tripping, even though none

of the switches are on for the mcb's in the kitchen load of the cu.



The kitchen load comprises of, 3 double sockets, 1 radiator switched

spur (RM with sockets), 1 cooker switch and a bathroom wall heater (RM

with sockets).



When I remove the earths from the kitchen/bathroom RM, the RCD will stay

on, but as soon as I touch either of the RM earth to the earth busbar,

it will trip the RCD. Also, I can leave the RM earths in and remove the

Neutral RM cables and it will be fine...but as soon as I touch the RM

neutral to the busbar, it trips. All connections are fine... to the

correct busbars, etc.



I am miffed on this one, and any help would be greatl;y appreciated!



Thanks.


Seems obvious its a neutral to earth connection somewhere.
RM?


NT

wrote:
On Friday, September 21, 2012 9:03:02 PM UTC+1, reeveer wrote:
Hi all.



New member here.



I am a qualified, registered electrician and I have a mojor problem
with

a new installation and rewiring.



I have rewired 6 new flats and fitted brand new cu's (B&Q £55
ones.. at

customer choice!).



Anyway, all rewire and fitting of consumer units of 5 flats are
fine...

however, the last one... did the rewire, fitted the cu, proceeded to

test and the rcd for the kitchen/bathroom is tripping, even though
none

of the switches are on for the mcb's in the kitchen load of the cu.



The kitchen load comprises of, 3 double sockets, 1 radiator switched

spur (RM with sockets), 1 cooker switch and a bathroom wall heater
(RM

with sockets).



When I remove the earths from the kitchen/bathroom RM, the RCD will
stay

on, but as soon as I touch either of the RM earth to the earth
busbar,

it will trip the RCD. Also, I can leave the RM earths in and remove
the

Neutral RM cables and it will be fine...but as soon as I touch the
RM

neutral to the busbar, it trips. All connections are fine... to the

correct busbars, etc.



I am miffed on this one, and any help would be greatl;y appreciated!



Thanks.


Seems obvious its a neutral to earth connection somewhere.


RM?

I was thinking that.

But as the OP has given no usefull info about the setup there is little
point in helping him.

FFS he spent more time giving info about the 5 flats that did work and and
the choice of CU than explaining the problem



--
Adam

On 22/09/2012 00:49, wrote:
On Friday, September 21, 2012 9:03:02 PM UTC+1, reeveer wrote:
Hi all.


Seems obvious its a neutral to earth connection somewhere.
RM?

"Ring Main" perhaps?


--
Cheers,

John.

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

On Saturday, September 22, 2012 2:41:04 AM UTC+1, John Rumm wrote:
On 22/09/2012 00:49, meow2222 wrote:

On Friday, September 21, 2012 9:03:02 PM UTC+1, reeveer wrote:

Hi all.





Seems obvious its a neutral to earth connection somewhere.

RM?



"Ring Main" perhaps?

Thank god I diy.


NT

wrote:

On Saturday, September 22, 2012 2:41:04 AM UTC+1, John Rumm wrote:
On 22/09/2012 00:49, meow2222 wrote:

On Friday, September 21, 2012 9:03:02 PM UTC+1, reeveer wrote:

Hi all.





Seems obvious its a neutral to earth connection somewhere.

RM?



"Ring Main" perhaps?

Thank god I diy.

Yes, that's his problem, he's got an 11,000v ring main in his flat.

--
To reply by e-mail, change the ' + ' to 'plus'.

Surely though that would not make either of them display the effect. I think
I'd try another rcd first in case its very over sensitive. there could
easily be some form of interference suppressor in an applience with a
thermostat that is causing a momentary blip.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"hugh" ] wrote in message
...
In message , Tim Watts
writes
reeveer wrote:


Hi all.

New member here.

I am a qualified, registered electrician and I have a mojor problem with
a new installation and rewiring.

I have rewired 6 new flats and fitted brand new cu's (B&Q 0 customer
choice!).

Anyway, all rewire and fitting of consumer units of 5 flats are fine...
however, the last one... did the rewire, fitted the cu, proceeded to
test and the rcd for the kitchen/bathroom is tripping, even though none
of the switches are on for the mcb's in the kitchen load of the cu.

The kitchen load comprises of, 3 double sockets, 1 radiator switched
spur (RM with sockets), 1 cooker switch and a bathroom wall heater (RM
with sockets).

When I remove the earths from the kitchen/bathroom RM, the RCD will stay
on, but as soon as I touch either of the RM earth to the earth busbar,
it will trip the RCD. Also, I can leave the RM earths in and remove the
Neutral RM cables and it will be fine...but as soon as I touch the RM
neutral to the busbar, it trips. All connections are fine... to the
correct busbars, etc.

I am miffed on this one, and any help would be greatl;y appreciated!

Thanks.

Were the IR tests in spec when you tested the circuit?

Did the RCD test as being in normal parameters in particular did it hold
in
on the x1 test?

What happens if you disconnect the fixed appliances?


Could it be that one of the appliances has the neutral linked to its
earth?
--
hugh

Brian Gaff wrote:
Surely though that would not make either of them display the effect. I think
I'd try another rcd first in case its very over sensitive. there could
easily be some form of interference suppressor in an applience with a
thermostat that is causing a momentary blip.
Brian


IF there is some neutral-earth solid bonding upstream of the RCD then
ANY earth neutral short will provide a path for neutral current that
bypasses the RCD by using the earth instead: That unbalances the RCD
enough to trip it on quiet small current draws.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

ARW wrote:

But as the OP has given no usefull info about the setup there is little
point in helping him.

FFS he spent more time giving info about the 5 flats that did work and and
the choice of CU than explaining the problem

Or a troll - he's been very quiet. Most people posting a question like that
would be on the net in short order looking for replies.

A real sparky, even a 4 day wonder[1], would probably have said they'd
tested the wiring and RCD (but probably without the appliances) and found
nothing wrong hence genuine confusion.

[1] On my 4-day-wonder course, the blatantly clueless and dangerous seemed
to leave after a couple of days. Everyone left could run the prescribed
tests and locate faults blind based on the tests.


--
Tim Watts

On Saturday, September 22, 2012 9:44:08 AM UTC+1, The Natural Philosopher wrote:
Brian Gaff wrote:

Surely though that would not make either of them display the effect. I think

I'd try another rcd first in case its very over sensitive. there could

easily be some form of interference suppressor in an applience with a

thermostat that is causing a momentary blip.

Brian





IF there is some neutral-earth solid bonding upstream of the RCD then

ANY earth neutral short will provide a path for neutral current that

bypasses the RCD by using the earth instead: That unbalances the RCD

enough to trip it on quiet small current draws.


I don't see how that can be right. Lots of properties have N&E connected upstream (PME), the RCD only cares about the downstream L/N current balance.


NT

In article ,
Brian Gaff wrote:
Surely though that would not make either of them display the effect. I
think I'd try another rcd first in case its very over sensitive. there
could easily be some form of interference suppressor in an applience
with a thermostat that is causing a momentary blip.

I'd hope the commissioning and testing of a new installation is done
without any 'appliances' plugged in. But even then, decent sockets are
double pole switched, so simply having them switched off would do.

--
*You can't teach an old mouse new clicks *

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 22 Sep 2012 09:28:49 +0100, Brian Gaff wrote:

Surely though that would not make either of them display the effect. I
think I'd try another rcd first in case its very over sensitive.

OP is supposed to be a "qualified, registered electrician", part of the
kit he needs to be that would include an RCD tester.

there could easily be some form of interference suppressor in an
applience with a thermostat that is causing a momentary blip.

No the description is such that the trip occurs instantly when ever N or
E are connected at the same time, not at some random point with something
else switching.

This chap is obviously only an "operator" press the button pass/fail, no
understanding of what he is doing, how things work and no abilty to fault
find. A "technician" should have enough knowledge of how RCDs and wiring
works to figure out what the fault must be. An "engineer" would know...

--
Cheers
Dave.

Graham. wrote:

What's wrong with those cheap BG CUs from B&Q? I'm tempted to replace
the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each circuit.
Far more expensive but well worth it. Far better.

I believe Weygand have double pole RCBOs which is better gain. But you may
need a commercial CU with the RCBOs run vertical. This is the best.

An RCD that controls a bank of mcb's is a waste of time. A problem on one
circuit can have the whole house switched - a daft idea.

On 22/09/2012 13:23, Doctor Drivel wrote:
Graham. wrote:

What's wrong with those cheap BG CUs from B&Q? I'm tempted to replace
the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each
circuit. Far more expensive but well worth it. Far better.

I believe Weygand have double pole RCBOs which is better gain. But you
may need a commercial CU with the RCBOs run vertical. This is the best.

An RCD that controls a bank of mcb's is a waste of time. A problem on
one circuit can have the whole house switched - a daft idea.

Whole house? Which edition are you working to?

Fredxx wrote:
On 22/09/2012 13:23, Doctor Drivel wrote:
Graham. wrote:

What's wrong with those cheap BG CUs from B&Q? I'm tempted to
replace the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each
circuit. Far more expensive but well worth it. Far better.

I believe Weygand have double pole RCBOs which is better gain. But
you may need a commercial CU with the RCBOs run vertical. This is
the best.

An RCD that controls a bank of mcb's is a waste of time. A problem on
one circuit can have the whole house switched - a daft idea.

Whole house? Which edition are you working to?

Nothing says it must be split.

Doctor Drivel wrote:
Fredxx wrote:
On 22/09/2012 13:23, Doctor Drivel wrote:
Graham. wrote:

What's wrong with those cheap BG CUs from B&Q? I'm tempted to
replace the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each
circuit. Far more expensive but well worth it. Far better.

I believe Weygand have double pole RCBOs which is better gain. But
you may need a commercial CU with the RCBOs run vertical. This is
the best.

An RCD that controls a bank of mcb's is a waste of time. A
problem on one circuit can have the whole house switched - a daft
idea.

Whole house? Which edition are you working to?

Nothing says it must be split.

Not even reg 314?

--
Adam

In article ,
Doctor Drivel wrote:
What's wrong with those cheap BG CUs from B&Q? I'm tempted to replace
the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each
circuit. Far more expensive but well worth it. Far better.

Gawd save us. He's claiming to know about electrics now.

--
*The early bird gets the worm, but the second mouse gets the cheese *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Fredxx wrote:
An RCD that controls a bank of mcb's is a waste of time. A problem on
one circuit can have the whole house switched - a daft idea.

Whole house? Which edition are you working to?

Dribble wouldn't know 'edition' if it bit him in the leg. It's one thing
him talking ****e about electric cars on here - but another when he
ventures into areas where he could do harm.

--
*When did my wild oats turn to prunes and all bran?

Dave Plowman London SW
To e-mail, change noise into sound.

"ARW" wrote in message
...
Doctor Drivel wrote:
Fredxx wrote:
On 22/09/2012 13:23, Doctor Drivel wrote:
Graham. wrote:

What's wrong with those cheap BG CUs from B&Q? I'm tempted to
replace the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each
circuit. Far more expensive but well worth it. Far better.

I believe Weygand have double pole RCBOs which is better gain. But
you may need a commercial CU with the RCBOs run vertical. This is
the best.

An RCD that controls a bank of mcb's is a waste of time. A
problem on one circuit can have the whole house switched - a daft
idea.

Whole house? Which edition are you working to?

Nothing says it must be split.

Not even reg 314?

No

"Dave Plowman (News)" wrote in message
...
In article ,
Fredxx wrote:
An RCD that controls a bank of mcb's is a waste of time. A problem on
one circuit can have the whole house switched - a daft idea.

Whole house? Which edition are you working to?

D

This man is senile....and an insane Jocko.

"Dave Plowman (News)" wrote in message
...
In article ,
Doctor Drivel wrote:
What's wrong with those cheap BG CUs from B&Q? I'm tempted to replace
the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each
circuit. Far more expensive but well worth it. Far better.

Gawd

This man is an idiot.

In article ,
Doctor Drivel wrote:

"ARW" wrote in message
...
Doctor Drivel wrote:
Fredxx wrote:
On 22/09/2012 13:23, Doctor Drivel wrote:
Graham. wrote:

What's wrong with those cheap BG CUs from B&Q? I'm tempted to
replace the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each
circuit. Far more expensive but well worth it. Far better.

I believe Weygand have double pole RCBOs which is better gain. But
you may need a commercial CU with the RCBOs run vertical. This is
the best.

An RCD that controls a bank of mcb's is a waste of time. A
problem on one circuit can have the whole house switched - a daft
idea.

Whole house? Which edition are you working to?

Nothing says it must be split.

Not even reg 314?

No

how about reading 314 before you make such pronouncements

--
From KT24

Using a RISC OS computer running v5.18

"charles" wrote in message
...
In article ,
Doctor Drivel wrote:

"ARW" wrote in message
...
Doctor Drivel wrote:
Fredxx wrote:
On 22/09/2012 13:23, Doctor Drivel wrote:
Graham. wrote:

What's wrong with those cheap BG CUs from B&Q? I'm tempted to
replace the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each
circuit. Far more expensive but well worth it. Far better.

I believe Weygand have double pole RCBOs which is better gain. But
you may need a commercial CU with the RCBOs run vertical. This is
the best.

An RCD that controls a bank of mcb's is a waste of time. A
problem on one circuit can have the whole house switched - a daft
idea.

Whole house? Which edition are you working to?

Nothing says it must be split.

Not even reg 314?

No

how about reading 314 before you make such pronouncements

I have!!!! Mandatory and advisory are not the same thing.

........
314.1 Every installation shall be divided into circuits, as necessary, to:
(i) avoid hazards and minimize inconvenience in the event of a fault
....
(iii) take account of danger that may arise from the failure of a single
circuit such as a lighting circuit.....
.......

To comply with 17th edition, circuits must be RCD protected if wiring is
concealed less than 50mm from the surface.

Having one RCD on all the system complies. Nothing in the regs says that a
CU must have two RCDs, or split load.

There is no specific Reg stating that you can't fit a consumer unit with
only one main RCD, 314 only "implies" that one should not have all final
circuits run off one RCD.

314 talks about spliting circuits such as lighting (upstairs and
downstairs).

In article , Doctor Drivel
wrote:

[Snip]

I have!!!! Mandatory and advisory are not the same thing.

....... 314.1 Every installation shall be divided into circuits, as
necessary, to: (i) avoid hazards and minimize inconvenience in the event
of a fault ...

That, I believe, to be the key point. If there is only one RCD hazards
will be created.

314.2 goes on to say "separate circuits shall be provided .... in such a
way that those circuits are not affected by the failure of other circuits."

A single RCD covering all circuits would not comply with this.

but then, I'm only a Chartered Electrical Engineer.



(iii) take account of danger that may arise from the
failure of a single circuit such as a lighting circuit..... ......

To comply with 17th edition, circuits must be RCD protected if wiring is
concealed less than 50mm from the surface.

Having one RCD on all the system complies. Nothing in the regs says that
a CU must have two RCDs, or split load.

There is no specific Reg stating that you can't fit a consumer unit with
only one main RCD, 314 only "implies" that one should not have all final
circuits run off one RCD.

314 talks about spliting circuits such as lighting (upstairs and
downstairs).

not in my copy.

--
From KT24

Using a RISC OS computer running v5.18

charles wrote:
In article , Doctor Drivel
wrote:

[Snip]

I have!!!! Mandatory and advisory are not the same thing.

....... 314.1 Every installation shall be divided into circuits, as
necessary, to: (i) avoid hazards and minimize inconvenience in the
event of a fault ...

That, I believe, to be the key point. If there is only one RCD
hazards will be created.

Hazards? One RCD creates a hazard? My oh my.

314.2 goes on to say "separate circuits shall be provided .... in
such a way that those circuits are not affected by the failure of
other circuits."

A single RCD covering all circuits would not comply with this.

Tripe. A circuit may fail and the mcb trips and the RCD does not. It means
splitting lights, sockets, etc, into separate circuits. I have the
integrated microwave on a separate circuit (could have been on a ring), as
was the cooker, fridge, washing machine, etc. All split. If one drops out on
an mcb the rest are OK - well I put in RCBOs which is besides the point.

but then, I'm only a Chartered Electrical Engineer.

I wouldn't hire you. I bet you think BS's are the regs as well.

In article ,
Doctor Drivel wrote:
charles wrote:
In article , Doctor Drivel
wrote:

[Snip]

I have!!!! Mandatory and advisory are not the same thing.

....... 314.1 Every installation shall be divided into circuits, as
necessary, to: (i) avoid hazards and minimize inconvenience in the
event of a fault ...

That, I believe, to be the key point. If there is only one RCD
hazards will be created.

Hazards? One RCD creates a hazard? My oh my.

yes, if something on one circuit takes out the single RCD, then all the
lights go out. If it's dark that IS the hazard.

314.2 goes on to say "separate circuits shall be provided .... in
such a way that those circuits are not affected by the failure of
other circuits."

A single RCD covering all circuits would not comply with this.

Tripe. A circuit may fail and the mcb trips and the RCD does not.

But if the RCD does trip?



I wouldn't hire you. I bet you think BS's are the regs as well.

How about BS7671:2008?

--
From KT24

Using a RISC OS computer running v5.18

charles wrote:
In article , Doctor Drivel
wrote:

[Snip]

I have!!!! Mandatory and advisory are not the same thing.

....... 314.1 Every installation shall be divided into circuits, as
necessary, to: (i) avoid hazards and minimize inconvenience in the
event of a fault ...

That, I believe, to be the key point. If there is only one RCD
hazards will be created.

I think two RCDs is better than one. DP RCBOs on all circuits is by far the
best. But the point is the regs do not state two RCDs are needed or a CU
split into two: one part with an RCD and one part unprotected. NOTHING
there states that. Look at words like shall, should , would, ect. You
think they all mean shall.

Legrand single RCD CU for sale:
http://www.screwfix.com/p/6-module-c...s-switch/60136

Note: not split.

On 22/09/2012 16:58, Doctor Drivel wrote:

"Dave Plowman (News)" wrote in message
...
In article ,
Fredxx wrote:
An RCD that controls a bank of mcb's is a waste of time. A problem on
one circuit can have the whole house switched - a daft idea.

Whole house? Which edition are you working to?

D

This man is senile....and an insane Jocko.

He may be senile, as indeed I might be as well. But we, and a few
others here, don't have our head in the sand and seemingly fail so badly
to appear knowledgeable.

Have you ever tried sitting the C&G 2382-12 exam? I have and I passed,
as indeed some others here will have done who question your "facts".

On 22/09/2012 13:31, Fredxx wrote:
On 22/09/2012 13:23, Doctor Drivel wrote:
Graham. wrote:

What's wrong with those cheap BG CUs from B&Q? I'm tempted to replace
the CU here with one.

Get a Wylex CU, the difference is apparent. And use RCBOs on each
circuit. Far more expensive but well worth it. Far better.

I believe Weygand have double pole RCBOs which is better gain. But you
may need a commercial CU with the RCBOs run vertical. This is the best.

An RCD that controls a bank of mcb's is a waste of time. A problem on
one circuit can have the whole house switched - a daft idea.

Whole house? Which edition are you working to?

The price is on the cover[1] in pounds shillings and pence...


[1] Ladybird book of house electrics probably...

--
Cheers,

John.

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

In article ,
Doctor Drivel wrote:

Tripe. A circuit may fail and the mcb trips and the RCD does not. It
means splitting lights, sockets, etc, into separate circuits. I have
the integrated microwave on a separate circuit (could have been on a
ring), as was the cooker, fridge, washing machine, etc. All split. If
one drops out on an mcb the rest are OK - well I put in RCBOs which is
besides the point.

If anyone was ever in any doubt about dribble being mad, here's the proof.

--
*OK, who stopped payment on my reality check?

Dave Plowman London SW
To e-mail, change noise into sound.

On Saturday, September 22, 2012 6:45:12 AM UTC+1, A.Lee wrote:
meow2222 wrote:

On Saturday, September 22, 2012 2:41:04 AM UTC+1, John Rumm wrote:

On 22/09/2012 00:49, meow2222 wrote:

On Friday, September 21, 2012 9:03:02 PM UTC+1, reeveer wrote:



Hi all.











Seems obvious its a neutral to earth connection somewhere.



RM?







"Ring Main" perhaps?



Thank god I diy.



Yes, that's his problem, he's got an 11,000v ring main in his flat.

Might explain why the bulbs don't last very long.


NT