UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Paul
 
Posts: n/a
Default Is my main socket ring too big?

I have a question for those expereienced electricians among us. I am buying
a new house,
and now that the second fix has been done and the CU installed I can see
that there is only a single ring serving the whole of the house sockets.
(additional circuits a lighting upstairs inc smoke alarms, lighting
downstairs, electric cooker).

I have serious reservations about this, as I was expecting two rings, one
upstairs, one downstairs.

I have done some reading of the uk.d-i-y FAQ, purchased IEE onsite guide to
16th
edition wiring regs, had a read on the web and spoken to the NHBC. The
general consensus of all
these is that the regulation states:

- Ring should not cover more than 100m^2

And thats about it. Now I am pretty confident that with a tumble dryer or
washing maching typically pulling up to 2-3KW each (washing machine is cold
draw only - Bosch), that all I have to do is boil the kettle (3KW) or have
the misses use a hairdryer (2-3KW) on washday and the ring will trip. Thats
not taking into account loads from things like Dishwashers, computers, TVs
and the like. This concerns me as (a) I have 2 computers I usually leave on
24/7 and they will not like it and (b) I have an alleregy to setting the
clocks on everything electronic and can barely cope with twice a year for
daylight savings!

Looking at the builders brochure, although their figure of 1000sqft would
mean 93m^2, they have taken the main foot print of the building. Calculating
with the protruding garage area at the front, and the protruding kitchen
area at the rear (all served by the same ring) the foot print is over
100m^2.

My Question: Can anyone tell me a way I can express the single ring being
overloaded referencing the IEE regulations?

I know that the 100m^2 figure is just a guide, but there are 34 sockets fed
from this ring, and I am sure I will be using nearly every one; its just not
up to the job. I am not sure how to prove that though quoting the
regulations, which is what I am going to need to do to get the builders to
take notice.

Thanks for any feedback

Paul

Email: paul at javajedi dot com


  #2   Report Post  
Andrew Gabriel
 
Posts: n/a
Default Is my main socket ring too big?

In article ,
"Paul" paul at javajedi dot com writes:
I have a question for those expereienced electricians among us. I am buying
a new house,
and now that the second fix has been done and the CU installed I can see
that there is only a single ring serving the whole of the house sockets.
(additional circuits a lighting upstairs inc smoke alarms, lighting
downstairs, electric cooker).

I have serious reservations about this, as I was expecting two rings, one
upstairs, one downstairs.


Would be helpful if you gave some idea of the size of the house
in terms of number/type of rooms. I'm presuming a 100m^2 house
can't have 4 bedrooms and a utility room, but maybe I'm way off?

I have done some reading of the uk.d-i-y FAQ, purchased IEE onsite guide to
16th
edition wiring regs, had a read on the web and spoken to the NHBC. The
general consensus of all
these is that the regulation states:

- Ring should not cover more than 100m^2

And thats about it. Now I am pretty confident that with a tumble dryer or
washing maching typically pulling up to 2-3KW each (washing machine is cold
draw only - Bosch),


Washing machine is high power only whilst it heats the water, which
is a short time.

that all I have to do is boil the kettle (3KW) or have


Even a full kettle can only be on a short time.

the misses use a hairdryer (2-3KW) on washday and the ring will trip. Thats


3kW? Is her hair made of asbostos? I never saw a 3kw hairdrier...

not taking into account loads from things like Dishwashers, computers, TVs
and the like. This concerns me as (a) I have 2 computers I usually leave on
24/7 and they will not like it and (b) I have an alleregy to setting the
clocks on everything electronic and can barely cope with twice a year for
daylight savings!


My Question: Can anyone tell me a way I can express the single ring being
overloaded referencing the IEE regulations?


No, because you haven't really given enough information to show
that it is.

You have got a standard cheap professional installation -- that
electrican was probably the cheapest quote the builder could get.
If you want a better quality installation, then welcome to the
world of D-I-Y...

--
Andrew Gabriel
  #3   Report Post  
Christian McArdle
 
Posts: n/a
Default Is my main socket ring too big?

My Question: Can anyone tell me a way I can express the single ring being
overloaded referencing the IEE regulations?


The ring should be capable of supporting the expected loads as well as the
100m3 restriction. I can't see how this could be said to be the case.
However, rather than an upstairs/downstairs split, it is most important that
the kitchen has its own. The loads in the rest of the house without electric
heating are likely to be tiny.

Sounds like they've blown the 100m3 anyway.

When partially rewiring my house, I've put several circuits just for the
kitchen. One 32A MCB radial powers only the dishwasher, washing machine and
tumble dryer. A 16A MCB radial does the fridge/freezer. A 32A RCBO ring
powers everything else (except lighting).

Christian.


  #4   Report Post  
 
Posts: n/a
Default Is my main socket ring too big?

Paul paul at javajedi dot com wrote:
I have a question for those expereienced electricians among us. I am buying
a new house,
and now that the second fix has been done and the CU installed I can see
that there is only a single ring serving the whole of the house sockets.
(additional circuits a lighting upstairs inc smoke alarms, lighting
downstairs, electric cooker).

I have serious reservations about this, as I was expecting two rings, one
upstairs, one downstairs.

I have done some reading of the uk.d-i-y FAQ, purchased IEE onsite guide to
16th
edition wiring regs, had a read on the web and spoken to the NHBC. The
general consensus of all
these is that the regulation states:

- Ring should not cover more than 100m^2

And thats about it. Now I am pretty confident that with a tumble dryer or
washing maching typically pulling up to 2-3KW each (washing machine is cold
draw only - Bosch), that all I have to do is boil the kettle (3KW) or have
the misses use a hairdryer (2-3KW) on washday and the ring will trip. Thats
not taking into account loads from things like Dishwashers, computers, TVs
and the like. This concerns me as (a) I have 2 computers I usually leave on
24/7 and they will not like it and (b) I have an alleregy to setting the
clocks on everything electronic and can barely cope with twice a year for
daylight savings!

It's unlikely that all these devices will draw all that power
simultaneously. Also, a hair dryer is usually only 750 to 100 watts,
nothing like the 2-3kW you suggest.


Looking at the builders brochure, although their figure of 1000sqft would
mean 93m^2, they have taken the main foot print of the building. Calculating
with the protruding garage area at the front, and the protruding kitchen
area at the rear (all served by the same ring) the foot print is over
100m^2.

My Question: Can anyone tell me a way I can express the single ring being
overloaded referencing the IEE regulations?

What you should really do is add up all the things you are likely to
have switched on simultaneously and then have a guess at the chances
of things which are on intermittently coming on simultaneously. You
may well find that the chances of tripping the circuit breaker are not
all that great.


I know that the 100m^2 figure is just a guide, but there are 34 sockets fed
from this ring, and I am sure I will be using nearly every one; its just not
up to the job. I am not sure how to prove that though quoting the
regulations, which is what I am going to need to do to get the builders to
take notice.

As you say the 100m2 is only a guide. 'Diversity' as outlined in the
OSG should also be applied, however you can only do this when actual
appliances are installed, the builders aren't really able to do it.

Having said all that I too would have expected two rings in a modern
house. How big a house is it - i.e. how many bedrooms etc.?

--
Chris Green )
  #5   Report Post  
 
Posts: n/a
Default Is my main socket ring too big?

Christian McArdle wrote:
My Question: Can anyone tell me a way I can express the single ring being
overloaded referencing the IEE regulations?


The ring should be capable of supporting the expected loads as well as the
100m3 restriction. I can't see how this could be said to be the case.


The builder can't tell as it's not really possible to know what will
be installed in new houses. If the house has no dishwasher, gas heating
and cooking, etc. then one ring main might well be OK.

--
Chris Green )


  #6   Report Post  
Christian McArdle
 
Posts: n/a
Default Is my main socket ring too big?

If the house has no dishwasher, gas heating and cooking, etc.
then one ring main might well be OK.


I would have thought that you could reasonably assume that a 100m3 house
will have a dishwasher, tumble dryer, washing machines, kettle, toaster,
oven, fridge freezer, iron and microwave in the kitchen. This is not a
studio flat we're talking about. Most old houses of this size would have
these appliances, let alone a brand new one.

Whether you can find a specific item in the regs preventing it, it is surely
not best practice and easy to conceive of long term overloadings occuring.
For the sake of an MCB and a few metres of cable, it isn't too much to ask
to do it right. Also, I hope there is a non-RCD side circuit for the
fridge/freezer. Very poor practice to omit this on a newbuild, when running
cable is so easy.

Christian.


  #7   Report Post  
Paul
 
Posts: n/a
Default Is my main socket ring too big?

Thanks to all those that replied, some additional information:

- House style is 3 bed, integrated garage at the front (half-in-half-out
style). Standard layout, i.e. no utility rooms or study etc downstairs or
general fancy bits.
- Accepted that hairdryer was exageration, and kettle is temporal load, but
point was if there is a situation that is going to occur on a regular basis,
such as washing machine and dryer both on, and the kettle load pushed it
over it would trip the breaker.
- It IS the builders expectation that all these things will be used in the
property. Primarily becuase the kitchen layout has 3 600mm openings, for
dishwasher, fridge and tumble dryer. So these loads at least are expected.
- There is no seperate ring/radial for the fridge, this I guess would have
made it more acceptable but as things stand all appliances are on 1 circuit
except the cooker and lights which have their own circuits.
- The socket circuit is all on the RCD, so stuck toast in the toaster is
likely to drop the lot.. (fridge as well).

I guess what it boils down to, is as some have observed, you would expect 2
rings in a modern house. I especially expect 2 rings given that its a modern
3 bed, at modern 3 bed prices, and its taken me several years to get to the
stage where I can buy one!

Apart from the load issue, I am also concerned about the earth. Modern
devices have a lot of earth leakage if they have switched mode power
supplies, although I believe this is now referred to as "high protective
conductor currents". Well, apart from several computers, I am sure that all
of video/dvd/hi-fi have switched mode PSU's in generating leakeage. Would
this be a problem? (I doubt it, but I am going to ask. I worked for a
company once that discovered one day that the top of the fuse box was
missing on their consumer unit, as it had melted due to the heat in the main
earth bar just underneath it!... lots switched mode PSU's = bad is the
message I left with!).

I guess from what I have seen so far, its pretty standard practice, and I
have to just live with the re-wire once I move in...

Cheers

Paul.

"Paul" paul at javajedi dot com wrote in message
...
I have a question for those expereienced electricians among us. I am

buying
a new house,
and now that the second fix has been done and the CU installed I can see
that there is only a single ring serving the whole of the house sockets.
(additional circuits a lighting upstairs inc smoke alarms, lighting
downstairs, electric cooker).

I have serious reservations about this, as I was expecting two rings, one
upstairs, one downstairs.

I have done some reading of the uk.d-i-y FAQ, purchased IEE onsite guide

to
16th
edition wiring regs, had a read on the web and spoken to the NHBC. The
general consensus of all
these is that the regulation states:

- Ring should not cover more than 100m^2

And thats about it. Now I am pretty confident that with a tumble dryer or
washing maching typically pulling up to 2-3KW each (washing machine is

cold
draw only - Bosch), that all I have to do is boil the kettle (3KW) or have
the misses use a hairdryer (2-3KW) on washday and the ring will trip.

Thats
not taking into account loads from things like Dishwashers, computers, TVs
and the like. This concerns me as (a) I have 2 computers I usually leave

on
24/7 and they will not like it and (b) I have an alleregy to setting the
clocks on everything electronic and can barely cope with twice a year for
daylight savings!

Looking at the builders brochure, although their figure of 1000sqft would
mean 93m^2, they have taken the main foot print of the building.

Calculating
with the protruding garage area at the front, and the protruding kitchen
area at the rear (all served by the same ring) the foot print is over
100m^2.

My Question: Can anyone tell me a way I can express the single ring being
overloaded referencing the IEE regulations?

I know that the 100m^2 figure is just a guide, but there are 34 sockets

fed
from this ring, and I am sure I will be using nearly every one; its just

not
up to the job. I am not sure how to prove that though quoting the
regulations, which is what I am going to need to do to get the builders to
take notice.

Thanks for any feedback

Paul

Email: paul at javajedi dot com




  #8   Report Post  
Christian McArdle
 
Posts: n/a
Default Is my main socket ring too big?

I am sure that all of video/dvd/hi-fi have switched mode PSU's
in generating leakeage.


Nah. Consumer goods are designed to not require an earth as many markets
round the world don't typically have earthed socket circuits. This is why
you always get fried by modern televisions, as their surface voltages float
off due to the internal 25kV generator. Without an earth to connect the RFI
suppression capacitors to, there is no way of generating earth leakage.

Christian.


  #9   Report Post  
 
Posts: n/a
Default Is my main socket ring too big?

In uk.d-i-y, Paul paul at javajedi dot com wrote:

I guess from what I have seen so far, its pretty standard practice, and I
have to just live with the re-wire once I move in...

I'm afraid you're about right there. It's barely-compliant skimping on the
part of the detail specifier (I won't dignify their actions by calling them
either an "architect" or a "design engineer"); your floor area is probably
just within the 100msq guideline (and it's only a *guideline* anyway, and
the Regs aren't legally binding in themselves anyway). But it's poor
practice, as you point out; the sage words of p.151 of the OSG, which
suggests "consideration should be given to a separate circuit" for
washing m/c, dryer, and wushdush to avoid unbalancing the legs of a ring
will be answered by the builder as "yup, we considered it [and then thought
about the extra 15 quid in materials and 30 in labour it would've cost,
and rejected it out of hand]"; and annoying too, since putting in two or
three rings (upstairs, down, and kitchen) would've been *much* easier
during construction than after the fact.

Still, at least you'll find out all about the quality of the electrical
installation when you do the upgrade - and you may be lucky (?) enough to
find a serious enough violation of the Regs that you can get the builders
to do a proper job (including the upgrade) as part of a hush-it-up deal ;-)

HTH, Stefek
Cheers

Paul.

"Paul" paul at javajedi dot com wrote in message
...
I have a question for those expereienced electricians among us. I am

buying
a new house,
and now that the second fix has been done and the CU installed I can see
that there is only a single ring serving the whole of the house sockets.
(additional circuits a lighting upstairs inc smoke alarms, lighting
downstairs, electric cooker).

I have serious reservations about this, as I was expecting two rings, one
upstairs, one downstairs.

I have done some reading of the uk.d-i-y FAQ, purchased IEE onsite guide

to
16th
edition wiring regs, had a read on the web and spoken to the NHBC. The
general consensus of all
these is that the regulation states:

- Ring should not cover more than 100m^2

And thats about it. Now I am pretty confident that with a tumble dryer or
washing maching typically pulling up to 2-3KW each (washing machine is

cold
draw only - Bosch), that all I have to do is boil the kettle (3KW) or have
the misses use a hairdryer (2-3KW) on washday and the ring will trip.

Thats
not taking into account loads from things like Dishwashers, computers, TVs
and the like. This concerns me as (a) I have 2 computers I usually leave

on
24/7 and they will not like it and (b) I have an alleregy to setting the
clocks on everything electronic and can barely cope with twice a year for
daylight savings!

Looking at the builders brochure, although their figure of 1000sqft would
mean 93m^2, they have taken the main foot print of the building.

Calculating
with the protruding garage area at the front, and the protruding kitchen
area at the rear (all served by the same ring) the foot print is over
100m^2.

My Question: Can anyone tell me a way I can express the single ring being
overloaded referencing the IEE regulations?

I know that the 100m^2 figure is just a guide, but there are 34 sockets

fed
from this ring, and I am sure I will be using nearly every one; its just

not
up to the job. I am not sure how to prove that though quoting the
regulations, which is what I am going to need to do to get the builders to
take notice.

Thanks for any feedback

Paul

Email: paul at javajedi dot com




  #10   Report Post  
Lawrence
 
Posts: n/a
Default Is my main socket ring too big?

Try speaking to builder about being unhappy, if no joy there and you
do not mind creating ripples speak to building control at the council.
It will probably be worth paying the builder £50 to split the ring
main. It will be a darn sight easier at this stage. Otherwise it will
be worth making a note of the cable routing for the ring main so you
can plan how to split it later.

Much as I appreaciate the desire to have a freezer of the RCD, I would
also not want to see the remaining kitchen appliances off the RCD. So
if I wanted the freezer separate then I would run a separate cable on
its own trip just for the freezer.


On Mon, 17 Nov 2003 14:00:07 -0000, "Paul" paul at javajedi dot com
wrote:

I have a question for those expereienced electricians among us. I am buying
a new house,
and now that the second fix has been done and the CU installed I can see
that there is only a single ring serving the whole of the house sockets.
(additional circuits a lighting upstairs inc smoke alarms, lighting
downstairs, electric cooker).

I have serious reservations about this, as I was expecting two rings, one
upstairs, one downstairs.

I have done some reading of the uk.d-i-y FAQ, purchased IEE onsite guide to
16th
edition wiring regs, had a read on the web and spoken to the NHBC. The
general consensus of all
these is that the regulation states:

- Ring should not cover more than 100m^2

And thats about it. Now I am pretty confident that with a tumble dryer or
washing maching typically pulling up to 2-3KW each (washing machine is cold
draw only - Bosch), that all I have to do is boil the kettle (3KW) or have
the misses use a hairdryer (2-3KW) on washday and the ring will trip. Thats
not taking into account loads from things like Dishwashers, computers, TVs
and the like. This concerns me as (a) I have 2 computers I usually leave on
24/7 and they will not like it and (b) I have an alleregy to setting the
clocks on everything electronic and can barely cope with twice a year for
daylight savings!

Looking at the builders brochure, although their figure of 1000sqft would
mean 93m^2, they have taken the main foot print of the building. Calculating
with the protruding garage area at the front, and the protruding kitchen
area at the rear (all served by the same ring) the foot print is over
100m^2.

My Question: Can anyone tell me a way I can express the single ring being
overloaded referencing the IEE regulations?

I know that the 100m^2 figure is just a guide, but there are 34 sockets fed
from this ring, and I am sure I will be using nearly every one; its just not
up to the job. I am not sure how to prove that though quoting the
regulations, which is what I am going to need to do to get the builders to
take notice.

Thanks for any feedback

Paul

Email: paul at javajedi dot com


Lawrence

usenet at lklyne dt co dt uk


  #11   Report Post  
Andrew Gabriel
 
Posts: n/a
Default Is my main socket ring too big?

In article ,
Lawrence writes:
Try speaking to builder about being unhappy, if no joy there and you
do not mind creating ripples speak to building control at the council.


Nothing listed was contrary to building regs. (Maybe something
else is, but getting that fixed won't solve original poster's
concerns.)

It will probably be worth paying the builder £50 to split the ring
main. It will be a darn sight easier at this stage.


I think that stage was passed before 2nd fix, and original poster
said he is past 2nd fix.

Much as I appreaciate the desire to have a freezer of the RCD, I would
also not want to see the remaining kitchen appliances off the RCD. So
if I wanted the freezer separate then I would run a separate cable on
its own trip just for the freezer.


Generally, when I rewire, I run two rings in the kitchen.
One is not RCD protected, and feeds all the large non-portable
appliances like fridge, freezer, washing machine, oven, dishwasher,
central heating (if applicable), none of which represent significant
electric shock risk, but in many cases represent some risk if their
power were to be lost. Socket outlets are all deliberately fairly
inaccessible and often unswitched. The second ring is RCD protected
and feeds all the readily accessible socket outlets for portable
appliances, which are the ones where RCD protection is most important.

--
Andrew Gabriel
  #12   Report Post  
 
Posts: n/a
Default Is my main socket ring too big?

Paul paul at javajedi dot com wrote:
Thanks to all those that replied, some additional information:

- House style is 3 bed, integrated garage at the front (half-in-half-out
style). Standard layout, i.e. no utility rooms or study etc downstairs or
general fancy bits.
- Accepted that hairdryer was exageration, and kettle is temporal load, but
point was if there is a situation that is going to occur on a regular basis,
such as washing machine and dryer both on, and the kettle load pushed it
over it would trip the breaker.

Kettle, probably 10 amps, they're rarely 3kW
Washing machine, maybe 12 amps
Hair dryer -3 or 4 amps
Total - 26 amps on a 32 amps circuit, still quite a bit of
'headroom'.

- It IS the builders expectation that all these things will be used in the
property. Primarily becuase the kitchen layout has 3 600mm openings, for
dishwasher, fridge and tumble dryer. So these loads at least are expected.


The fridge is pretty irrelevant in consumption terms.


- There is no seperate ring/radial for the fridge, this I guess would have
made it more acceptable but as things stand all appliances are on 1 circuit
except the cooker and lights which have their own circuits.


There are really only three circuits, that does seem pretty stingy.


- The socket circuit is all on the RCD, so stuck toast in the toaster is
likely to drop the lot.. (fridge as well).

Why should stuck toast trip the RCD?


Apart from the load issue, I am also concerned about the earth. Modern
devices have a lot of earth leakage if they have switched mode power
supplies, although I believe this is now referred to as "high protective
conductor currents". Well, apart from several computers, I am sure that all
of video/dvd/hi-fi have switched mode PSU's in generating leakeage. Would
this be a problem? (I doubt it, but I am going to ask. I worked for a
company once that discovered one day that the top of the fuse box was
missing on their consumer unit, as it had melted due to the heat in the main
earth bar just underneath it!... lots switched mode PSU's = bad is the
message I left with!).

I think something has got exagerrated and or 'lost in the wash' here,
the heating effect of the sort of earth leakage you are talking about
would be negligable.

--
Chris Green )
  #13   Report Post  
Owain
 
Posts: n/a
Default Is my main socket ring too big?

"Christian McArdle" wrote
| Whether you can find a specific item in the regs preventing it,
| it is surely not best practice and easy to conceive of long term
| overloadings occuring.
| For the sake of an MCB and a few metres of cable, it isn't too
| much to ask to do it right. Also, I hope there is a non-RCD side
| circuit for the fridge/freezer. Very poor practice to omit this
| on a newbuild, when running cable is so easy.

I hope there isn't a whole-house 30mA RCD installed ...

Seems to me having one circuit where the design current of the circuit is
foreseeably inadequate would contravene the Fundamental Requirements for
Safety:

130-02-02 All equipment shall be suitable for the maximum power demanded by
the current-using equipment when it is functioning in its intended manner

and

314-01-01 Every installation shall be divided into circuits as necessary
to:
(i) avoid danger in the event of a fault, and
(ii) facilitate safe operation, inspection, testing and maintenance

Having only one socket circuit means if there is a fault on that circuit
there is no power to use tools etc

314-01-02 A separate circuit shall be provided ... so that such circuits
shall remain energised in the event of failure of any other circuit of the
installation, and due account shall be taken of the consequences of the
operation of any single protective device

This would also restrict the use of a whole-house 30mA RCD. Of particular
concern is the fact that the garage socket seems to be on this circuit too.

The circuit is also going to have to be carefully designed. From memory, the
Volt Drop of 2.5mm is about 19mV per A per metre cable (depending on
mounting method). If we envision a 100m2 house as being a single-storey
square 10x10m that means an perimeter ring of 40m. 40metres x 0.019 x 32A
design current = about 24V or 10% of the mains voltage unless I've counted
fingers wrong. Considering this could be powering the electric lawnmower at
the bottom of the garden on an extension lead there is no spare drop really.
There is also Zs of the circuit to consider, will it be adequate with the
length of cable.

Of course, as the job is being done properly the Design, Installation,
Inspection and Test three-part certificate will be signed by a competent
person on all three parts, and the schedule of circuits will give cable
length, conductor size, and Zs for each circuit, so it will be easy for the
builder to demonstrate the Regs are being complied with by supplying that
certificate together with copies of the signer's C&G or other qualifications
as proof of competence.

Owain




  #14   Report Post  
Chris Oates
 
Posts: n/a
Default Is my main socket ring too big?


"Paul" paul at javajedi dot com wrote in message
. ..

Apart from the load issue, I am also concerned about the earth. Modern
devices have a lot of earth leakage if they have switched mode power
supplies, although I believe this is now referred to as "high protective
conductor currents". Well, apart from several computers, I am sure that

all
of video/dvd/hi-fi have switched mode PSU's in generating leakeage. Would
this be a problem?

Not normally - at work I run SMPSs and nasty motors on RCDs
Neutral currents get a bit weird with harmonics



  #15   Report Post  
Paul
 
Posts: n/a
Default Is my main socket ring too big?

Thanks for the feedback everyone, positive and negative. I can see there is
some division on if its OK, or stretching regs, but clearly the consensus is
its a poor solution. I just know now I am going to have to sort it out
afterwards anyway, I am just pretty mad that I have such a "just within
guidelines" result for the money I am paying.

I did a quick count last night, and I have 18 plugs under my desk alone (a
few big loads, lots brick style PSU's) and if nothing else I am sure I am
going to have lots of noise on one large ring (I can already listen to my
ADSL router PSU on my cheap'n'cheerful unfltered clock radio in the mornings
at my current place).

2nd fix has already taken place, and I can't see the builder doing anything
now (painters are in). Thanks to Owain for the very detailed reply. I had
considered voltage drop due to length of the ring, I will have to get my
thinking hat on and do the calculations, this will be a real issue when
taking an extension to the back garden if I wanted to use the garage sockets
as you pointed out. In reply to your question, the CU is split, the RCD side
has a single circuit which is the sockets ring, so I guess yes, the whole
house is on a single RCD (except the cooker) and it is probably a 30mA
device, I will check next time I am at the site.

As Stefak points out, the ring is supposed to be evenly loaded, but all they
have done is run the ring round the ceiling joists on the ground floor
pulling it up to the bedrooms and down to the other rooms. As the CU is in
the garage, and the first stop on the ring is the kitchen the ring is
massivly unbalanced!

I guess all I can do is obtain copies of the electricians certification for
the installation to BS7671 when the sale completes. The NHBC warrenty will
cover me when all the problems start, I could just do without settling in,
then having to consider ripping walls/ceilings/floors apart to get an
electricity supply that does not keep tripping...

I can see some people on the group think I am being dramatic, but I am a bit
of a gadet freak with plenty of electrical appliances, and can assure you
that my concerns are real.

Cheers all, just found uk.d-i-y, think I might be here for a while... very
helpful group!

Paul

Email: paul at javajedi dot com




  #16   Report Post  
 
Posts: n/a
Default Is my main socket ring too big?

In uk.d-i-y, Paul paul at javajedi dot com wrote:

...................., the ring is supposed to be evenly loaded, but all they
have done is run the ring round the ceiling joists on the ground floor
pulling it up to the bedrooms and down to the other rooms. As the CU is in
the garage, and the first stop on the ring is the kitchen the ring is
massivly unbalanced!

As the Currant Bun says, "gotcha!" The unbalanced loading on the ring
strikes me as a clear violation of good design practice, and is *specifically*
mentioned on the page of the OSG wot I quoted (and the note in the margin
traces back to reg 433-02-04). I think it's time to put your concerns in
writing: a *short* letter - try to keep it down to 1 page of A4 - saying
you believe the design of the electrical installation to be inadequate for
normal pattern of occupation (don't say "I'm a gadget freak", just say
"dushwush, washmash, tumble-drumble" (or rather the more common forms
of the names for those appliances!) and other kitchen appliances, plus
normal appliances upstairs, make overheating of shorter leg of run to
kitchen a foreseeable hazard.

(Also, if the cabling goes up and down between ground and first floors
repeatedly in the way you mention, its total length may be getting
close to the limits for a 30A/32A 2.5mmsq ring - 88/84m resp. for a
normal Type B MCB: and that hacked design contributes materially to the
unbalanced loading of the legs of the ring feeding the kitchen. The
conventional design of an upstairs ring which would go up once, feed
bedroom etc. sockets, and then come down, would be much more appropriate.)

Ask for a response in writing. Have you paid for the house yet? Can you
retain money for (a) getting an independent inspection, and (b) rectifying?
Make it clear you're questioning the design of the electrics in *all* the
houses slapped up to this design, not some wacko requirements which your
own current-consumption-obsession produces ;-) If you do want to pursue
this you will need a qualified electrical installation designer's opinion
to put up against theirsr. If you can face the investment of time and energy,
you might find that one of the medium-sized local companies in your area
would be happy to do this as a 50-quid inspection-cert job and throw in
a couple-of-para amplifying letter as a way of venting their frustration
at being undercut by whichever cabling-cowboy got the contract for this
build ;-)

Only you can judge, of course, whether it's worth your while raising this
amount of stink with the developers, or whether to shrug your shoulders and
prepare for a wiring upgrade as you move in.

Good luck with whatever you decide - Stefek

  #18   Report Post  
Christian McArdle
 
Posts: n/a
Default Is my main socket ring too big?

I don't have any regs or tables on me to calculate what that limit
is due to, but if it's the earth fault loop impedance, then the RCD
effectively overcomes that limit.


I thought it was seriously frowned upon to rely on an RCD for earth fault
impedence problems, unless it was a TT system and the problems were due to
(relatively) high earth rod impedence?

Christian.


  #19   Report Post  
Andy Wade
 
Posts: n/a
Default Is my main socket ring too big?

"Christian McArdle" wrote in message
t...

I thought it was seriously frowned upon to rely on an RCD for earth
fault impedence problems, unless it was a TT system and the problems
were due to (relatively) high earth rod impedence?


You can debate that one until the cows come home, but it's an academic point
in this case. Type B MCB protected rings since are voltage drop limited.

--
Andy


  #20   Report Post  
Mike Tomlinson
 
Posts: n/a
Default Is my main socket ring too big?

In article , Paul
writes

I guess what it boils down to, is as some have observed, you would expect 2
rings in a modern house.


I would expect three; downstairs, upstairs and kitchen/utility.

--
A. Top posters.
Q. What's the most annoying thing on Usenet?



  #21   Report Post  
Mike Tomlinson
 
Posts: n/a
Default Is my main socket ring too big?

In article , Paul
writes

The NHBC warrenty will
cover me when all the problems start


Sure about that? It seems to be regarded as pretty useless, an
organisation funded by the builders themselves...

--
A. Top posters.
Q. What's the most annoying thing on Usenet?

  #22   Report Post  
ARWadsworth
 
Posts: n/a
Default Is my main socket ring too big?


"Mike Tomlinson" wrote in message
...
In article , Paul
writes

The NHBC warrenty will
cover me when all the problems start


Sure about that? It seems to be regarded as pretty useless, an
organisation funded by the builders themselves...


I have seen new builds that have NHBC certificates but no NICEIC certificate
and heating that does not meet the new regs.

--
Adam



--
A. Top posters.
Q. What's the most annoying thing on Usenet?



  #23   Report Post  
Paul
 
Posts: n/a
Default Is my main socket ring too big?

"Mike Tomlinson" wrote

Sure about that? It seems to be regarded as pretty useless, an
organisation funded by the builders themselves...


I would argue that the NHBC has its place, given that the mortgage lenders
seem to regard it as a necessary to ensure any defects are rectified. Don't
forget if the builder is registered, and folds, NHBC conducts repairs etc
should they become required.

I don't however assume it covers everything, I called them (NHBC) up about
the wiring, and they were quite vauge, and just referred me to the BS7671
spec as being required to be met.

Paul.


  #24   Report Post  
Paul
 
Posts: n/a
Default Is my main socket ring too big?


"ARWadsworth" wrote in message
...

I have seen new builds that have NHBC certificates but no NICEIC

certificate
and heating that does not meet the new regs.


What relevance is NICEIC though? I thought they were just a guild for
electricians, they still work to BS7671 which is the UK standard for
electrical installations? (or am I missing something).

Paul.


  #25   Report Post  
ARWadsworth
 
Posts: n/a
Default Is my main socket ring too big?


"Paul" paul at javajedi dot com wrote in message
...
"Mike Tomlinson" wrote

Sure about that? It seems to be regarded as pretty useless, an
organisation funded by the builders themselves...


I would argue that the NHBC has its place, given that the mortgage lenders
seem to regard it as a necessary to ensure any defects are rectified.

Don't
forget if the builder is registered, and folds, NHBC conducts repairs etc
should they become required.

I don't however assume it covers everything, I called them (NHBC) up about
the wiring, and they were quite vauge, and just referred me to the BS7671
spec as being required to be met.


And what is better than an NIC certificate to show that the requirements are
met? It also allows a builder to pass the buck.

--
Adam




Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Extending socket circuit to a ring? Chris UK diy 16 October 13th 03 10:47 AM
Extending a spurred socket Matthew Barnard UK diy 2 September 3rd 03 10:45 PM
Question regarding adding an extra socket to the ring main Fiona Reid UK diy 10 September 3rd 03 05:45 PM
extending a ring main Paul Draper UK diy 7 July 4th 03 08:43 PM


All times are GMT +1. The time now is 12:24 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"