Is there anything that says an MCB rating for a ring main has to be 32
amps, could it be 16 amps?
I want to put my kitchen on its own circuit but the MCB's are no longer
made by Crabtree but I have two unused 16 amp MCB's.
If I use the 32 amp that is currently the downstairs ring main for the
kitchen then put the front room/hall on one 16 amp ring and the living
room on another 16 amp ring would I run into problems?

Kevin

You might get some nuisance tripping if you try doing the hoovering and
ironing whilst watching a DVD with surround sound by the light of a
collection of floor lamps :-)

"Kev" wrote in message
oups.com...
Is there anything that says an MCB rating for a ring main has to be 32
amps, could it be 16 amps?
I want to put my kitchen on its own circuit but the MCB's are no longer
made by Crabtree but I have two unused 16 amp MCB's.
If I use the 32 amp that is currently the downstairs ring main for the
kitchen then put the front room/hall on one 16 amp ring and the living
room on another 16 amp ring would I run into problems?

Kevin


Are you are refering to the Crabtree MCBs that came before the plug in type?
ie is it a screw the fastens the MCB to the bus bar?
If so then I was able to buy a 40 amp one from Newey and Eyres last week. I
did have to order it in but it did arrive the next day. I am also sure I
will have an old type 32 amp MCB knocking about in the garage, it will be
guaranteed second hand but I will post it to you if you want.

Adam

Kev wrote:
Is there anything that says an MCB rating for a ring main has to be 32
amps, could it be 16 amps?
I want to put my kitchen on its own circuit but the MCB's are no longer
made by Crabtree but I have two unused 16 amp MCB's.
If I use the 32 amp that is currently the downstairs ring main for the
kitchen then put the front room/hall on one 16 amp ring and the living
room on another 16 amp ring would I run into problems?

Kevin

it can be 16 if you want. 16A mcbs dont trip at 16.1A, and as long as
you dont have kitchen, immersion or electric heating on them, all
should be fine.

NT

Hi;

Good idea to have a seperate final ring circuit in the kitchen.
Most sparks I know who do this would use 4m T&E as well.

If you have the kettle on, switch the toaster on while the kettle boils
then warn the beans up in a Micro wave, what happens ?

Didn't trip, Umm, now the fridge kicks in and it does trip!!

Is it worth the cost of a 32 Amp MCB ?

Who is going to Insect and Test this for your Part P certificate?
I would probably fail it on the grounds of the MCB being too small to
take a kitchen load by exposing the MCB to too much in overcurrent
operations. What if the MCB failed in the ON position, Presto - No
protection and you would not know - hence the need for Part P.

Then, perhaps the Kettle is on the cooker switch and all is fine.

Regards
Ian

Kev wrote:
Is there anything that says an MCB rating for a ring main has to be 32
amps, could it be 16 amps?

16th ed IEE wiring regs is very lean on requirements for ring circuits.
Most of the stuff in earlier editions has been taken out and appears
(if it does) in the IEE On-Site Guide - mostly in Appendix 8. There's
some relevant additional info in Appendix 1 (diversity).

Appendix 8 implies that ring final circuits should be protected at 30A
or 32A & be run using cable rated = 20A - ie =2.5mmsq if in FTE.

Possibly there is a further implication in Appendix 8, that if you use
BS1363 socket outlets (the std uk flat pin type) then any ring they are
inserted in must comply table 8A - ie for a ring circuit you need
30/32A MCB.


I want to put my kitchen on its own circuit but the MCB's are no longer
made by Crabtree but I have two unused 16 amp MCB's.

If I use the 32 amp that is currently the downstairs ring main for the
kitchen then put the front room/hall on one 16 amp ring and the living
room on another 16 amp ring would I run into problems?

Frankly a false economy. Use some of the money you are saving by DIY
to do a proper job with fittings that will last. Invest in a new CU if
you possibly can.

HTH

jim_in_sussex wrote:

Frankly a false economy. Use some of the money you are saving by DIY
to do a proper job with fittings that will last. Invest in a new CU if
you possibly can.

Although there's nothing wrong with the OP's idea of using the one
available 32 A MCB for the kitchen ring and splitting the other ring
into two radial circuits, assuming each circuit covers 50 m^2 floor
area. However, these should be 20 A circuits, not 16 A. With 16 A MCBs
they would be non-standard circuits and could be seen as under-rated for
general household loading - likely to be overloaded if the CH breaks
down and all those old electric heaters come out, for example.

--
Andy

ARWadsworth wrote:
"Kev" wrote in message
oups.com...
Is there anything that says an MCB rating for a ring main has to be 32
amps, could it be 16 amps?
I want to put my kitchen on its own circuit but the MCB's are no longer
made by Crabtree but I have two unused 16 amp MCB's.
If I use the 32 amp that is currently the downstairs ring main for the
kitchen then put the front room/hall on one 16 amp ring and the living
room on another 16 amp ring would I run into problems?

Kevin


Are you are refering to the Crabtree MCBs that came before the plug in type?
ie is it a screw the fastens the MCB to the bus bar?
If so then I was able to buy a 40 amp one from Newey and Eyres last week. I
did have to order it in but it did arrive the next day. I am also sure I
will have an old type 32 amp MCB knocking about in the garage, it will be
guaranteed second hand but I will post it to you if you want.

Adam
It is a plugin type. The current starbreakers have exactly the same
type if fitting and are interchangeable but the newer ones stick out
more and are supposed to foul the front cover slightly. I may just try
one and see. The cover has a lip that I could file down a bit if the
fit interfears.

Kevin

wrote:
Hi;

Good idea to have a seperate final ring circuit in the kitchen.
Most sparks I know who do this would use 4m T&E as well.

If you have the kettle on, switch the toaster on while the kettle boils
then warn the beans up in a Micro wave, what happens ?

Didn't trip, Umm, now the fridge kicks in and it does trip!!

Is it worth the cost of a 32 Amp MCB ?

Who is going to Insect and Test this for your Part P certificate?
I would probably fail it on the grounds of the MCB being too small to
take a kitchen load by exposing the MCB to too much in overcurrent
operations. What if the MCB failed in the ON position, Presto - No
protection and you would not know - hence the need for Part P.

Then, perhaps the Kettle is on the cooker switch and all is fine.

Regards
Ian

I will put the existing 32 amp on the kitchen. That would leave two
unused 16 amp MCB's, one for the front room/hall and one for the living
room. If I could get an old type plugin 32 amp I would but tracking one
down is the problem.

Kevin

Owain wrote:
wrote:
Good idea to have a seperate final ring circuit in the kitchen.
Most sparks I know who do this would use 4m T&E as well.
If you have the kettle on, switch the toaster on while the kettle boils
then warn the beans up in a Micro wave, what happens ?
Didn't trip, Umm, now the fridge kicks in and it does trip!!

Serves you right for putting the fridge on the socket circuit, then.
Fridges better on their own non-RCD circuit (except TT installs,
obvoiusly). But that's usually too much work for a "pro" sparks.

Anyway, kettle = 2kW, toaster = 2kW, m/wave = 1kw

total = 7kW, within loading of 32A ring.

If kettle 3kW then a short term overload, which should be well within
the parameters of the ring if the cable and MCB are correctly sized
together.

Is it worth the cost of a 32 Amp MCB ?
Who is going to Insect and Test this for your Part P certificate?
I would probably fail it on the grounds of the MCB being too small to
take a kitchen load by exposing the MCB to too much in overcurrent
operations.

What?

What if the MCB failed in the ON position, Presto - No
protection and you would not know - hence the need for Part P.

Exactly how does Part P make any difference to the IEE wiring regs and
the BS for circuit breakers?

Then, perhaps the Kettle is on the cooker switch and all is fine.

If you think having kettles on cooker switches is fine I'm not letting
you near my house.

Owain
In my case the fridge and the freezer are on their own unprotected
circuit anyway so that wouldn't be a problem.

Kevin

jim_in_sussex wrote:


If I use the 32 amp that is currently the downstairs ring main for the
kitchen then put the front room/hall on one 16 amp ring and the living
room on another 16 amp ring would I run into problems?

Frankly a false economy. Use some of the money you are saving by DIY
to do a proper job with fittings that will last. Invest in a new CU if
you possibly can.

HTH

I have thought of a new CU but am I then not into the realms of having
the whole installation in the house tested. Somebody at work went that
route then got his house electrics condemned because of something that
was donkeys years old wasn't up to spec.
The work involved would be minimal if only I could trace a suitable
MCB.

Kevin

"Kev" wrote in message
ups.com...

ARWadsworth wrote:
"Kev" wrote in message
oups.com...
Is there anything that says an MCB rating for a ring main has to be 32
amps, could it be 16 amps?
I want to put my kitchen on its own circuit but the MCB's are no longer
made by Crabtree but I have two unused 16 amp MCB's.
If I use the 32 amp that is currently the downstairs ring main for the
kitchen then put the front room/hall on one 16 amp ring and the living
room on another 16 amp ring would I run into problems?

Kevin


Are you are refering to the Crabtree MCBs that came before the plug in
type?
ie is it a screw the fastens the MCB to the bus bar?
If so then I was able to buy a 40 amp one from Newey and Eyres last week.
I
did have to order it in but it did arrive the next day. I am also sure I
will have an old type 32 amp MCB knocking about in the garage, it will be
guaranteed second hand but I will post it to you if you want.

Adam
It is a plugin type. The current starbreakers have exactly the same
type if fitting and are interchangeable but the newer ones stick out
more and are supposed to foul the front cover slightly. I may just try
one and see. The cover has a lip that I could file down a bit if the
fit interfears.

Kevin

I also have those types of MCBs knocking about if you want one.

Adam

Andy Wade wrote:
jim_in_sussex wrote:

Frankly a false economy. Use some of the money you are saving by DIY
to do a proper job with fittings that will last. Invest in a new CU if
you possibly can.

Although there's nothing wrong with the OP's idea of using the one
available 32 A MCB for the kitchen ring and splitting the other ring
into two radial circuits,

....but unless I have very much misunderstood the original post, the
suggestion was to break the circuit into 2 separate 16A rings.

As you suggest breaking it into 2 radials is perfectly OK (or even just
making it into 1 20A radial) & might make the OP's MCB hunt easier as
finding a 20A MCB would also put him back in business.

How does the risk of reusing old MCBs untested rate versus installing a
brand new reputable make CU with only basic continuity testing ? My
money would go on a the new CU as the safer bet.

If the OP is reusing old second hand MCBs then perhaps he should
consider testing them properly.

"jim_in_sussex" wrote in message
oups.com...

Andy Wade wrote:
jim_in_sussex wrote:

Frankly a false economy. Use some of the money you are saving by DIY
to do a proper job with fittings that will last. Invest in a new CU if
you possibly can.

Although there's nothing wrong with the OP's idea of using the one
available 32 A MCB for the kitchen ring and splitting the other ring
into two radial circuits,

...but unless I have very much misunderstood the original post, the
suggestion was to break the circuit into 2 separate 16A rings.

As you suggest breaking it into 2 radials is perfectly OK (or even just
making it into 1 20A radial) & might make the OP's MCB hunt easier as
finding a 20A MCB would also put him back in business.

How does the risk of reusing old MCBs untested rate versus installing a
brand new reputable make CU with only basic continuity testing ?

How do you test an MCB?

Adam

ARWadsworth wrote:

How do you test an MCB?

Pass current through it and see if it trips. Use a variac and a
low-voltage high current transformer, and wind the current up slowly.
Not really necessary though, since (IME) they never fail, unlike RCDs.

--
Andy

"Andy Wade" wrote in message
...
jim_in_sussex wrote:

Frankly a false economy. Use some of the money you are saving by DIY
to do a proper job with fittings that will last. Invest in a new CU if
you possibly can.

Although there's nothing wrong with the OP's idea of using the one
available 32 A MCB for the kitchen ring and splitting the other ring into
two radial circuits, assuming each circuit covers 50 m^2 floor area.
However, these should be 20 A circuits, not 16 A. With 16 A MCBs they
would be non-standard circuits and could be seen as under-rated for
general household loading - likely to be overloaded if the CH breaks down
and all those old electric heaters come out, for example.

--
Andy

Why do garage/shed CUs usually arrive pre loaded with one 16 amp and one 6
amp breaker?

Adam

"Andy Wade" wrote in message
...
ARWadsworth wrote:

How do you test an MCB?

Pass current through it and see if it trips. Use a variac and a
low-voltage high current transformer, and wind the current up slowly. Not
really necessary though, since (IME) they never fail, unlike RCDs.

--
Andy

That is not a test used on any NICEIC inspection. Maybe it should be.

Adam

On Wed, 07 Jun 2006 23:45:50 GMT, "ARWadsworth"
wrote:


"Andy Wade" wrote in message
...
jim_in_sussex wrote:

Frankly a false economy. Use some of the money you are saving by DIY
to do a proper job with fittings that will last. Invest in a new CU if
you possibly can.

Although there's nothing wrong with the OP's idea of using the one
available 32 A MCB for the kitchen ring and splitting the other ring into
two radial circuits, assuming each circuit covers 50 m^2 floor area.
However, these should be 20 A circuits, not 16 A. With 16 A MCBs they
would be non-standard circuits and could be seen as under-rated for
general household loading - likely to be overloaded if the CH breaks down
and all those old electric heaters come out, for example.

--
Andy

Why do garage/shed CUs usually arrive pre loaded with one 16 amp and one 6
amp breaker?

Adam

Power and light.

jim

16th ed IEE wiring regs is very lean on requirements for ring circuits.
Most of the stuff in earlier editions has been taken out and appears
(if it does) in the IEE On-Site Guide - mostly in Appendix 8. There's
some relevant additional info in Appendix 1 (diversity).

I think this is why quality sparks use radials in the kitchen.
Ring final circuits are rather a UK under specified specification that
maybe are OK in todays low power cumsumable appliances found in all but
the kitchen. I suspect that the worst case a rfc would cope with is the
Vac starting up or the lawnmower getting clogged on a wet lawn. Go into
EU sparking areas and its all redials.

As 17th addition is round the corner we await with abated breath.

Yes I hope to have my 2391 soon (Exam mid July) so I can legally apply
my hate of the amount poor sparking near and around me. My dad has a
huge column drill on a 13amp extension lead with 1.5T&E, of course the
earth wire has fractured and he complains of a tingle when drilling !!
Perhaps Mum is waiting for his eyes for glow !!

Regards
Ian

Go into EU sparking areas and its all redials.

Yes, but they get 16A socket circuits with limited sockets on each circuit.
It is only UK style systems that give us the flexibility to go around
sticking 3kW appliances in where we see fit and have some chance of not
blowing a fuse.

Christian.

wrote in message
ups.com...
SNIP



Yes I hope to have my 2391 soon (Exam mid July) so I can legally
apply
my hate of the amount poor sparking near and around me. My dad has a
huge column drill on a 13amp extension lead with 1.5T&E, of course
the
earth wire has fractured and he complains of a tingle when drilling
!!
Perhaps Mum is waiting for his eyes for glow !!

Regards
Ian


Now as I understand health and safety law in a work environment NOBODY
from the bog cleaner up to the CEO can avoid blame if they become
aware of a problem and do nothing about it. In a home / family
situation surely the moral issue is even stronger if not the law, and
particularly if an individual is training / trained in the area of
hazzard . . .

AWEM

On Thu, 8 Jun 2006 16:57:30 +0100, "Andrew Mawson"
wrote:

Now as I understand health and safety law in a work environment NOBODY
from the bog cleaner up to the CEO can avoid blame if they become
aware of a problem and do nothing about it.

That came in at the end of the 70's, and a jolly shock it was to
employers. "Safety Officers" were appointed immediately,(Me),
regardless of how little they knew.

When I enquired, I was told to see if we had "any loose carpet on the
stairs".

I went around and listed defects and gave them to the manager. He
binned it, but I had a copy on file elsewhere and had shown it to
other staff. )

"EricP" wrote in message
...
On Wed, 07 Jun 2006 23:45:50 GMT, "ARWadsworth"
wrote:


"Andy Wade" wrote in message
.. .
jim_in_sussex wrote:

Frankly a false economy. Use some of the money you are saving by DIY
to do a proper job with fittings that will last. Invest in a new CU if
you possibly can.

Although there's nothing wrong with the OP's idea of using the one
available 32 A MCB for the kitchen ring and splitting the other ring
into
two radial circuits, assuming each circuit covers 50 m^2 floor area.
However, these should be 20 A circuits, not 16 A. With 16 A MCBs they
would be non-standard circuits and could be seen as under-rated for
general household loading - likely to be overloaded if the CH breaks
down
and all those old electric heaters come out, for example.

--
Andy

Why do garage/shed CUs usually arrive pre loaded with one 16 amp and one 6
amp breaker?

Adam

Power and light.

So they should come with 20A and a 6A then

Adam

wrote:
jim

16th ed IEE wiring regs is very lean on requirements for ring circuits.
Most of the stuff in earlier editions has been taken out and appears
(if it does) in the IEE On-Site Guide - mostly in Appendix 8. There's
some relevant additional info in Appendix 1 (diversity).

I think this is why quality sparks use radials in the kitchen.
Ring final circuits are rather a UK under specified specification that
maybe are OK in todays low power cumsumable appliances found in all but
the kitchen. I suspect that the worst case a rfc would cope with is the
Vac starting up or the lawnmower getting clogged on a wet lawn. Go into
EU sparking areas and its all redials.

the benefits of ring circuits seem to be often not understood

As 17th addition is round the corner we await with abated breath.

youll die if you do that


Yes I hope to have my 2391 soon (Exam mid July) so I can legally apply
my hate of the amount poor sparking near and around me.

Best learn why our ring system has both safety and cost advanatages
over radials then. Otherwise you'll be one more bad electrician.


NT

It scares me as to why there are people saying that rings are not needed in Domestic premises Ring mains are especially needed in the kitchen area where there is a higher KW usage. an A1 ring should be 32A with 2.5mm2 twin and earth and to make sure there is only 1 spur of each socket otherwise you are creating a Radial circuit of a ring which is overload territory. Also the ring has the advantage of still having the rest of the Socket outlets working if one of the cables fail in between sockets whereas a radial will fail all the other outlets if the previous socket has a fault.

A2 Radial = 32A 4.0mm2
A3 Radial = 20A 2.5mm2

correct me if im wrong

Level 3 qualified 2330

By the way how many idiots out there still are no good at fault finding

Continuity test ring a bell