My house was built and wired in the 1980s and has an old-style fuse box.
The old fuses have all been repeplaced with cirquit-breakers plugged into
the fuse sockets. A couple of people, such as estate agents and
electricians have raised eyebrows on seeing the box, telling me it should
be changed for a modern RCD unit. Is this true? I've never had any problems
with the existing setup, and I rarely get any inexplicable tripping of the
circuit breakers. As far as I am aware, the old fuse boxes (even when fuses
contained fuse wire) did what they were designed to do, with no problems.

My fuse box has circuit-breakers for:
Upstairs ring main
Downstairs ring main
Upstairs light circuit
Downstairs lighting circuit
Electric shower circuit
External security lights circuit

Obviously, I'd like to avoid the expense of updating it if I'm not under
any legal obligation to change anything. Is there really a significant
increase in electrical safety with the modern RCD units?

What about if I rent the house to tenants? Will it then need to comply with
the latest electrical regulation specs?

THanks for some help.

Jim

On Sunday, 21 June 2015 23:20:25 UTC+1, Jim x321x wrote:
My house was built and wired in the 1980s and has an old-style fuse box.

then no, in most cases

The old fuses have all been repeplaced with cirquit-breakers plugged into
the fuse sockets. A couple of people, such as estate agents and
electricians have raised eyebrows on seeing the box, telling me it should
be changed for a modern RCD unit. Is this true?

no

I've never had any problems
with the existing setup, and I rarely get any inexplicable tripping of the
circuit breakers. As far as I am aware, the old fuse boxes (even when fuses
contained fuse wire) did what they were designed to do, with no problems.

My fuse box has circuit-breakers for:
Upstairs ring main
Downstairs ring main
Upstairs light circuit
Downstairs lighting circuit
Electric shower circuit
External security lights circuit

Obviously, I'd like to avoid the expense of updating it if I'm not under
any legal obligation to change anything.

you're not

Is there really a significant
increase in electrical safety with the modern RCD units?

There are 20 something deaths from shock a year, mostly due to people doing idiotic things. RCDs reduce the risk. This is a long way down the list of Risky Things in Life, so is the oposite of a priority.


NT

What about if I rent the house to tenants? Will it then need to comply with
the latest electrical regulation specs?

On 21/06/2015 23:20, Jim x321x wrote:

My house was built and wired in the 1980s and has an old-style fuse box.
The old fuses have all been repeplaced with cirquit-breakers plugged into
the fuse sockets. A couple of people, such as estate agents and
electricians have raised eyebrows on seeing the box, telling me it should
be changed for a modern RCD unit. Is this true? I've never had any problems

There is no legal requirement to change it.

with the existing setup, and I rarely get any inexplicable tripping of the
circuit breakers. As far as I am aware, the old fuse boxes (even when fuses
contained fuse wire) did what they were designed to do, with no problems.

They did what they were supposed to - and will still do so. The main
thing your current setup lacks is RCD protection.

My fuse box has circuit-breakers for:
Upstairs ring main
Downstairs ring main
Upstairs light circuit
Downstairs lighting circuit
Electric shower circuit
External security lights circuit

Obviously, I'd like to avoid the expense of updating it if I'm not under
any legal obligation to change anything. Is there really a significant
increase in electrical safety with the modern RCD units?

RCDs represent a significant improvement in safety. Especially if you
ever use electrical tools / appliances outside. The lack of RCD
protection would also make adding or extending your existing
installation in a compliant way more difficult, should you need to do so.

(some will argue that the chances of being killed by an electric shock
in the home in the UK is vanishingly small, and indeed they are correct.
However that misses the significant number of non fatal injuries per
year (200K hospital admissions), the vast majority of which would have
been prevented by a working RCD).

What about if I rent the house to tenants? Will it then need to comply with
the latest electrical regulation specs?

As long as its basically sound, then not necessarily. Many landlords
would take the view that replacing rewireable fuses is worth doing since
it removes the ability for tenants to abuse them, and possibly prevents
some call outs to the landlord / maintainer because they can't work out
how to replace a blown fuse.


--
Cheers,

John.

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

Chris Hogg wrote:

Is it possible to get what I think are called RCBO's,
(i.e. a combination of overload cut-out, MCB, with a residual current
device, RCD), that plug into the slots currently occupied by the wire
fuse holders

Plug-in MCBs are possible because they only require the same two
contacts (live in and out) that the old fuses used, but an RCBO requires
additional contacts (neutral in and out and an earth) so not feasible as
a plug-in replacement.

Andy Burns wrote:

an RCBO requires additional contacts (neutral in and out and an
earth)

Which makes me ask another question ...
Why does an RCBO require a functional earth, when an RCD doesn't?

On Sunday, 21 June 2015 23:20:25 UTC+1, Jim x321x wrote:
My house was built and wired in the 1980s and has an old-style fuse box.
The old fuses have all been repeplaced with cirquit-breakers plugged into
the fuse sockets.

There can be issues with doing this. Certain designs have gaps between the MCBs and the cover which would fail modern ingress protection rating against poking things in. Also the plug-in MCBs sometimes have a lower breaking capacity than 'conventional' MCBs.

For rental property electrics have to be 'safe' (and in Scotland from later this year, have an EICR - electrical condition report).

Given the age and current circuit arrangements it's likely that replacing the CU would be a fairly straightforward swap if the original wiring hasn't been buggered about with.

For renting you would also need mains powered interlinked smoke detectors.

Owain

On Monday, June 22, 2015 at 8:27:58 AM UTC+1, Andy Burns wrote:
Andy Burns wrote:

an RCBO requires additional contacts (neutral in and out and an
earth)

Which makes me ask another question ...
Why does an RCBO require a functional earth, when an RCD doesn't?

The earth connection enables the RCBO to trip even with a lost neutral connection.

wrote:

Andy Burns wrote:

Why does an RCBO require a functional earth, when an RCD doesn't?

The earth connection enables the RCBO to trip even with a lost neutral connection.

I'm curious why have we ended-up with RCBOs that generally do have an FE
connection and RCDs that generally don't?

Well, I've never come across any rented property that has the very latest
fuse box/rcd. But that may just be coincidence. I do not go around checking
everyones houses I visit for rcds, only that a blind person can safely reach
the reset buttons!
In any case if you are using an outside applience, you use a plug in rcd
and then its as safe as anything can be.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"John Rumm" wrote in message
...
On 21/06/2015 23:20, Jim x321x wrote:

My house was built and wired in the 1980s and has an old-style fuse box.
The old fuses have all been repeplaced with cirquit-breakers plugged into
the fuse sockets. A couple of people, such as estate agents and
electricians have raised eyebrows on seeing the box, telling me it should
be changed for a modern RCD unit. Is this true? I've never had any
problems

There is no legal requirement to change it.

with the existing setup, and I rarely get any inexplicable tripping of
the
circuit breakers. As far as I am aware, the old fuse boxes (even when
fuses
contained fuse wire) did what they were designed to do, with no problems.

They did what they were supposed to - and will still do so. The main thing
your current setup lacks is RCD protection.

My fuse box has circuit-breakers for:
Upstairs ring main
Downstairs ring main
Upstairs light circuit
Downstairs lighting circuit
Electric shower circuit
External security lights circuit

Obviously, I'd like to avoid the expense of updating it if I'm not under
any legal obligation to change anything. Is there really a significant
increase in electrical safety with the modern RCD units?

RCDs represent a significant improvement in safety. Especially if you ever
use electrical tools / appliances outside. The lack of RCD protection
would also make adding or extending your existing installation in a
compliant way more difficult, should you need to do so.

(some will argue that the chances of being killed by an electric shock in
the home in the UK is vanishingly small, and indeed they are correct.
However that misses the significant number of non fatal injuries per year
(200K hospital admissions), the vast majority of which would have been
prevented by a working RCD).

What about if I rent the house to tenants? Will it then need to comply
with
the latest electrical regulation specs?

As long as its basically sound, then not necessarily. Many landlords would
take the view that replacing rewireable fuses is worth doing since it
removes the ability for tenants to abuse them, and possibly prevents some
call outs to the landlord / maintainer because they can't work out how to
replace a blown fuse.


--
Cheers,

John.

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

wrote:
For renting you would also need mains powered interlinked smoke
detectors.


In England? I'm not a landlord but several neighbours are and from their
chatter I thought even the new regs which apply from October only
required a smoke alarm on every floor - ie no need for mains powered or
interlinked in a bog standard non-HMO.

--
Robin
reply to address is (meant to be) valid

John Rumm wrote in
:

with the existing setup, and I rarely get any inexplicable tripping
of the circuit breakers. As far as I am aware, the old fuse boxes
(even when fuses contained fuse wire) did what they were designed to
do, with no problems.

They did what they were supposed to - and will still do so. The main
thing your current setup lacks is RCD protection.


Thanks to all for the excellently helpful advice.

If I added an RCD covering the entire house (without replacing the existing
fuse box which is already fitted with MCBs, would that constitute a change
to the wiring and thus require building control notification?

Would doing this significantly improve the house's safety rating in the
eyes of, say, a house-purchaser's surveyor?

I note that in another thread recently, someone seemed alarmed that someone
was planning to install an electric shower without RCD protection. That's
partly what got me thinking about this issue.

Jim

wrote in
:

My house was built and wired in the 1980s and has an old-style fuse
box.

The old fuses have all been repeplaced with cirquit-breakers plugged
into

the fuse sockets.

There can be issues with doing this. Certain designs have gaps between
the MCBs and the cover which would fail modern ingress protection
rating against poking things in. Also the plug-in MCBs sometimes have
a lower breaking capacity than 'conventional' MCBs.

Thanks. I have to admit, that there *is*, arguably an issue with the
plastic cover that originally covered all the fuses. The subsequently-
installed MCBs stick out to far to allow the old cover to be attached. So I
simply left it off. My thinking was that MCBs should probably be in plain
view anyway, because one should be able to access them quickly. Also,
unenlightened tenenats and/or their guests might not know where the MCbs
are located if they were all covered with an opaque plastic cover that's
screwed on.

I suppose I could quite easily modify the cover to make it deep enough to
cover the MCBs without obstructing free flip-switch operation.

BTW, I am in England, so not bound by regional Scottish regulations.

Jim

John Rumm wrote in news:S8SdnWOCa5G-
:

(some will argue that the chances of being killed by an electric shock
in the home in the UK is vanishingly small, and indeed they are correct.
However that misses the significant number of non fatal injuries per
year (200K hospital admissions), the vast majority of which would have
been prevented by a working RCD).

Thanks for the input. You confirm what I thought. In fact, it seems likely
to me that more accidents are likely to be caused by a house's power being
unexpectedly cut off due to a RCD misdiagnosing a fault - especially at
night. Elderly an infirm people suddenly finding themselves walking around
in pitch darkness, having to fumble their way to the CU. Surely that would
be a dangersous situation for some, no? It would be interesting to know the
statistics regarding how many people have suffered injury that way, vs. how
many have suffered injury due to a fuse failing to blow, or a MCB failing
to trip.

Jim

Jim x321x wrote:

it seems likely to me that more accidents are likely to be caused by
a house's power being unexpectedly cut off due to a RCD misdiagnosing
a fault - especially at night. Elderly an infirm people suddenly
finding themselves walking around in pitch darkness, having to fumble
their way to the CU.

Hence newer installations having at least two RCDs with circuits split
between them, or RCBOs per circuit, so that faults on one circuit affect
fewer (or no) other circuits ... rather than being in pitch darkness you
could get a bit of light from upstairs reaching downstairs, or use
floor/table lights instead of ceiling lights etc.

On 22/06/2015 09:06, Brian-Gaff wrote:
Well, I've never come across any rented property that has the very latest
fuse box/rcd. But that may just be coincidence. I do not go around checking
everyones houses I visit for rcds, only that a blind person can safely reach
the reset buttons!

Indeed - how would you cope with re-wireing a BS3036 style fuse?

In any case if you are using an outside applience, you use a plug in rcd
and then its as safe as anything can be.

Yup that will help.


--
Cheers,

John.

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

On 22/06/2015 09:56, Jim x321x wrote:
John Rumm wrote in
:

with the existing setup, and I rarely get any inexplicable tripping
of the circuit breakers. As far as I am aware, the old fuse boxes
(even when fuses contained fuse wire) did what they were designed to
do, with no problems.

They did what they were supposed to - and will still do so. The main
thing your current setup lacks is RCD protection.


Thanks to all for the excellently helpful advice.

If I added an RCD covering the entire house (without replacing the existing
fuse box which is already fitted with MCBs, would that constitute a change
to the wiring and thus require building control notification?

Firstly you don't want a single RCD covering the whole house - that is a
practice that was common during the 15th edition, but is deprecated now
since it offers no "discrimination" in the event of a fault (i.e. the
fault will take out the supply to the whole house, not just the circuit
causing the problem). So many circuits on one RCD are also more prone to
nuisance tripping in the first place.

Changing a CU is "notifiable", although if done right no one is going to
whinge if you don't.

Would doing this significantly improve the house's safety rating in the
eyes of, say, a house-purchaser's surveyor?

Only if the purchaser is sufficiently clued up. You may find an older CU
etc would be commented on during a survey, but only in as much as the
surveyor might comment that you could get an electrical report if
concerned.

So if your only reason for the change is to make the house more
saleable, I would not bother. If however you are planning to carry on
living there, then its worth it (IMHO) for other reasons.

I note that in another thread recently, someone seemed alarmed that someone
was planning to install an electric shower without RCD protection. That's
partly what got me thinking about this issue.

Its possible to install a shower safely without one - and prior to the
17th edition it was possible (and not uncommon) to do so. Having said
that, its very sensible to include a RCD for a shower, and now the 17th
edition mandates it.

For your installation with relatively few circuits, the "nicest"
solution would be an "all RCBO" installation. That is one where you use
RCBOs (Residual Current Circuit breaker with Overload protection) - i.e.
a combined MCB and RCD in one. That way you get the best of both worlds
RCD protection on every circuit, but also perfect discrimination - a RCD
trip will only deactivate the circuit with the fault and leave the rest
untouched.

--
Cheers,

John.

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

On 22/06/2015 10:13, Jim x321x wrote:
John Rumm wrote in news:S8SdnWOCa5G-
:

(some will argue that the chances of being killed by an electric shock
in the home in the UK is vanishingly small, and indeed they are correct.
However that misses the significant number of non fatal injuries per
year (200K hospital admissions), the vast majority of which would have
been prevented by a working RCD).

Thanks for the input. You confirm what I thought. In fact, it seems likely
to me that more accidents are likely to be caused by a house's power being
unexpectedly cut off due to a RCD misdiagnosing a fault - especially at
night. Elderly an infirm people suddenly finding themselves walking around
in pitch darkness, having to fumble their way to the CU. Surely that would
be a dangersous situation for some, no?

This is why the "whole house" RCD setup is now no longer permitted.
Trips and falls in the house are more likely to injure people than
electric shocks in the first place.

It would be interesting to know the
statistics regarding how many people have suffered injury that way, vs. how
many have suffered injury due to a fuse failing to blow, or a MCB failing
to trip.

RCDs (in this scenario) are primarily about shock protection from what
used to be called "direct contact" (now "basic protection") - i.e. you
come into contact with something that is supposed to be live, but you
are not normally supposed to be able to touch it (e.g. a cut flex on the
mower). MCBs and Fuses offer almost *no* direct contact protection since
the current that flows through you is insufficient to trip a MCB or blow
a fuse - but still plenty to injure or kill you.

Fuses and MCBs only offer shock protection in "indirect contact" or
"fault protection" scenarios - i.e. preventing shocks from coming into
contact with metalwork that should *not* be live normally, but has
become so as a result of a fault. (since said metal work should be
earthed, that creates a path for a large fault current to flow, which in
turn with de-energise the circuit due to operation of the MCB/fuse.


--
Cheers,

John.

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

On 22/06/2015 08:15, Chris Hogg wrote:
Not answering your question, but adding one of my own as I have a
similar situation in my mother's house. She has an old fuse box with
wired fuses. Is it possible to get what I think are called RCBO's,
(i.e. a combination of overload cut-out, MCB, with a residual current
device, RCD), that plug into the slots currently occupied by the wire
fuse holders, or does that require a whole new consumer unit?

You can get plug in MCBs for old Wylex style boxes, but not plug in
RCBOs, since a RCBO needs the neutral to pass through it as well as the
live, and there is no access to that from the socket on the fusebox.


--
Cheers,

John.

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

On 22/06/2015 11:05, John Rumm wrote:
For your installation with relatively few circuits, the "nicest"
solution would be an "all RCBO" installation. That is one where you use
RCBOs (Residual Current Circuit breaker with Overload protection) - i.e.
a combined MCB and RCD in one. That way you get the best of both worlds
RCD protection on every circuit, but also perfect discrimination - a RCD
trip will only deactivate the circuit with the fault and leave the rest
untouched.

The OP mentioned separate upstairs and downstairs light circuits. It's
possible that the landing light might have "borrowed" the neutral from
downstairs. If so this would need to be rectified before RCBO's could be
used for these two circuits.

--
Mike Clarke

On 22/06/2015 08:27, Andy Burns wrote:
Andy Burns wrote:

an RCBO requires additional contacts (neutral in and out and an
earth)

Which makes me ask another question ...
Why does an RCBO require a functional earth, when an RCD doesn't?

They don't necessarily, although some do have one.

The additional earth connection allows the RCD section to trip on
additional fault scenarios that would not otherwise be detected.


--
Cheers,

John.

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

On Monday, 22 June 2015 04:51:01 UTC+1, John Rumm wrote:
On 21/06/2015 23:20, Jim x321x wrote:

My house was built and wired in the 1980s and has an old-style fuse box.
The old fuses have all been repeplaced with cirquit-breakers plugged into
the fuse sockets. A couple of people, such as estate agents and
electricians have raised eyebrows on seeing the box, telling me it should
be changed for a modern RCD unit. Is this true? I've never had any problems

There is no legal requirement to change it.

with the existing setup, and I rarely get any inexplicable tripping of the
circuit breakers. As far as I am aware, the old fuse boxes (even when fuses
contained fuse wire) did what they were designed to do, with no problems.

They did what they were supposed to - and will still do so. The main
thing your current setup lacks is RCD protection.

My fuse box has circuit-breakers for:
Upstairs ring main
Downstairs ring main
Upstairs light circuit
Downstairs lighting circuit
Electric shower circuit
External security lights circuit

Obviously, I'd like to avoid the expense of updating it if I'm not under
any legal obligation to change anything. Is there really a significant
increase in electrical safety with the modern RCD units?

RCDs represent a significant improvement in safety. Especially if you
ever use electrical tools / appliances outside. The lack of RCD
protection would also make adding or extending your existing
installation in a compliant way more difficult, should you need to do so.

(some will argue that the chances of being killed by an electric shock
in the home in the UK is vanishingly small, and indeed they are correct.
However that misses the significant number of non fatal injuries per
year (200K hospital admissions), the vast majority of which would have
been prevented by a working RCD).

RCDs greatly shorten shock duration of L-E shocks. They don't act on L-N shocks.
Someone going to hospital because they got scared doesn't mean they're injured.


NT

On Monday, 22 June 2015 09:56:09 UTC+1, Jim x321x wrote:

If I added an RCD covering the entire house (without replacing the existing
fuse box which is already fitted with MCBs, would that constitute a change
to the wiring and thus require building control notification?

Would doing this significantly improve the house's safety rating in the
eyes of, say, a house-purchaser's surveyor?

not a bit. The standard survey phrase is you should get everything checked, which people normally don't do. If they're fool enough to do so, the very predictable outcome for most houses is it doesn't meet all latest regs. They're none the wiser, but have parted with money at the time they can least afford it.


NT

On Mon, 22 Jun 2015 00:44:32 -0700, wrote:


The earth connection enables the RCBO to trip even with a lost neutral
connection.

Would the residual current breaker still work on a PME system where the
incoming gas and water pipes were plastic?

Where would such an installation be getting its earth from in the event
of a lost neutral?

On Monday, 22 June 2015 11:05:10 UTC+1, John Rumm wrote:
On 22/06/2015 09:56, Jim x321x wrote:
John Rumm wrote in
:

with the existing setup, and I rarely get any inexplicable tripping
of the circuit breakers. As far as I am aware, the old fuse boxes
(even when fuses contained fuse wire) did what they were designed to
do, with no problems.

They did what they were supposed to - and will still do so. The main
thing your current setup lacks is RCD protection.


Thanks to all for the excellently helpful advice.

If I added an RCD covering the entire house (without replacing the existing
fuse box which is already fitted with MCBs, would that constitute a change
to the wiring and thus require building control notification?

Firstly you don't want a single RCD covering the whole house - that is a
practice that was common during the 15th edition, but is deprecated now
since it offers no "discrimination" in the event of a fault (i.e. the
fault will take out the supply to the whole house, not just the circuit
causing the problem). So many circuits on one RCD are also more prone to
nuisance tripping in the first place.

A single RCD is moderately likely to not even work.


Would doing this significantly improve the house's safety rating in the
eyes of, say, a house-purchaser's surveyor?

Only if the purchaser is sufficiently clued up. You may find an older CU
etc would be commented on during a survey, but only in as much as the
surveyor might comment that you could get an electrical report if
concerned.

Surveys say get it checked regardless. A buyer that understands RCDs - few do - is one that can do the job themselves if they want.


So if your only reason for the change is to make the house more
saleable, I would not bother. If however you are planning to carry on
living there, then its worth it (IMHO) for other reasons.

Work out the cost & size of risk reduction. Compare with other options. The benefit per pound is far from top of the list.


NT

On 22/06/2015 04:51, John Rumm wrote:

(some will argue that the chances of being killed by an electric shock
in the home in the UK is vanishingly small,

About the same as the chance of winning the lottery (give or take a
factor of 10), yet many people buy lottery tickets.

On 22/06/2015 11:05, John Rumm wrote:

So if your only reason for the change is to make the house more
saleable, I would not bother.


If you simply want to make it more saleable, you could perhaps put a
dummy new-style fuse box in a prominent position, and lock the cupboard
with the real one in.

On Mon, 22 Jun 2015 10:54:02 +0100, John Rumm
wrote:

On 22/06/2015 09:06, Brian-Gaff wrote:
Well, I've never come across any rented property that has the very latest
fuse box/rcd. But that may just be coincidence. I do not go around checking
everyones houses I visit for rcds, only that a blind person can safely reach
the reset buttons!

Indeed - how would you cope with re-wireing a BS3036 style fuse?

I bet Brian could do that with no problem.
I bet you and I could do it blindfolded it we tried, I never have!

I've re spooled plenty of 35mm cassettes using a changing bag, and
loaded various film sizes into the spiral if a developing tank in
complete darkness.

I'm not suggesting for a moment that a sighted person in the dark
equates to a blind person. That would indeed be arrogant.



--

Graham.

%Profound_observation%

On 22/06/2015 12:52, Graham. wrote:
On Mon, 22 Jun 2015 10:54:02 +0100, John Rumm
wrote:

On 22/06/2015 09:06, Brian-Gaff wrote:
Well, I've never come across any rented property that has the very latest
fuse box/rcd. But that may just be coincidence. I do not go around checking
everyones houses I visit for rcds, only that a blind person can safely reach
the reset buttons!

Indeed - how would you cope with re-wireing a BS3036 style fuse?

I bet Brian could do that with no problem.
I bet you and I could do it blindfolded it we tried, I never have!

More than likely - but familiarity is the key (and knowing what you are
trying to achieve)

For an unskilled user attempting to identify the failed fuse, locate the
right rating of spare fuse wire, effecting the replacement and then
getting the fuse back into the CU - all in the dark, when you have never
even bother looking at the fuse box in the past, is quite a "big ask"!
Especially when compared to finding which MCB has tripped and flipping
the switch.

I've re spooled plenty of 35mm cassettes using a changing bag, and
loaded various film sizes into the spiral if a developing tank in
complete darkness.

Indeed, same here.

I always have a small pen knife in my pocket with a screwdriver that
would be adequate to rewire a wylex fuse as well. I suspect I am in the
minority though when it comes to preparedness for fuse re-wiring ;-)

I'm not suggesting for a moment that a sighted person in the dark
equates to a blind person. That would indeed be arrogant.

I would expect a sighted person in the dark to perform substantially
less well than a blind one.

--
Cheers,

John.

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

On 22/06/2015 11:18, Mike Clarke wrote:
On 22/06/2015 11:05, John Rumm wrote:
For your installation with relatively few circuits, the "nicest"
solution would be an "all RCBO" installation. That is one where you use
RCBOs (Residual Current Circuit breaker with Overload protection) - i.e.
a combined MCB and RCD in one. That way you get the best of both worlds
RCD protection on every circuit, but also perfect discrimination - a RCD
trip will only deactivate the circuit with the fault and leave the rest
untouched.

The OP mentioned separate upstairs and downstairs light circuits. It's
possible that the landing light might have "borrowed" the neutral from
downstairs. If so this would need to be rectified before RCBO's could be
used for these two circuits.

Indeed - there are a few potential problems to crawl out of the
woodwork. Probably worth anyone thinking o doing their own CU swap,
having a read through of:

http://wiki.diyfaq.org.uk/index.php?..._consumer_unit




--
Cheers,

John.

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On 22/06/2015 11:37, wrote:
On Monday, 22 June 2015 11:05:10 UTC+1, John Rumm wrote:
On 22/06/2015 09:56, Jim x321x wrote:
John Rumm wrote in
:

with the existing setup, and I rarely get any inexplicable
tripping of the circuit breakers. As far as I am aware, the
old fuse boxes (even when fuses contained fuse wire) did
what they were designed to do, with no problems.

They did what they were supposed to - and will still do so.
The main thing your current setup lacks is RCD protection.


Thanks to all for the excellently helpful advice.

If I added an RCD covering the entire house (without replacing
the existing fuse box which is already fitted with MCBs, would
that constitute a change to the wiring and thus require building
control notification?

Firstly you don't want a single RCD covering the whole house -
that is a practice that was common during the 15th edition, but is
deprecated now since it offers no "discrimination" in the event of
a fault (i.e. the fault will take out the supply to the whole
house, not just the circuit causing the problem). So many circuits
on one RCD are also more prone to nuisance tripping in the first
place.

A single RCD is moderately likely to not even work.

True, but the failure rate is not high enough to make that relevant I
would say. (IIRC, 15% of those that have never been tested may fail to
operate when they should - but that sill leaves 75% that will work and
potentially prevent an injury)

Would doing this significantly improve the house's safety rating
in the eyes of, say, a house-purchaser's surveyor?

Only if the purchaser is sufficiently clued up. You may find an
older CU etc would be commented on during a survey, but only in as
much as the surveyor might comment that you could get an
electrical report if concerned.

Surveys say get it checked regardless. A buyer that understands RCDs
- few do - is one that can do the job themselves if they want.

Indeed. Hence my comment about it not being something that will help
"sell" a house.

So if your only reason for the change is to make the house more
saleable, I would not bother. If however you are planning to carry
on living there, then its worth it (IMHO) for other reasons.

Work out the cost & size of risk reduction. Compare with other
options. The benefit per pound is far from top of the list.

If your only criterion is avoidance of death due to electrocution, then
the argument is plausible, since from a statistical point of view you
may as well ignore the risk of death - its low enough to be insignificant.

None of that however diminishes the effectiveness of a RCD at preventing
shock injury - the occurrences of which are commonplace rather than
rare. (100's K of hospital admissions per year)


--
Cheers,

John.

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\================================================= ================/

On 22/06/2015 11:42, GB wrote:
On 22/06/2015 11:05, John Rumm wrote:

So if your only reason for the change is to make the house more
saleable, I would not bother.


If you simply want to make it more saleable, you could perhaps put a
dummy new-style fuse box in a prominent position, and lock the cupboard
with the real one in.

You jest, but I have seen similar...

One place which had been "fully rewired", actually had nice new sockets
and light switches etc in conspicuous places, and shiny new CU. Its only
when you looked closely you realised the nice new lengths of T&E exiting
the CU went all of two feet before being joined back onto the old rubber
insulated cables under the floor, and that most of the sockets were not
even wired up!


--
Cheers,

John.

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

On 22/06/2015 11:28, wrote:
On Monday, 22 June 2015 04:51:01 UTC+1, John Rumm wrote:
On 21/06/2015 23:20, Jim x321x wrote:

My house was built and wired in the 1980s and has an old-style fuse box.
The old fuses have all been repeplaced with cirquit-breakers plugged into
the fuse sockets. A couple of people, such as estate agents and
electricians have raised eyebrows on seeing the box, telling me it should
be changed for a modern RCD unit. Is this true? I've never had any problems

There is no legal requirement to change it.

with the existing setup, and I rarely get any inexplicable tripping of the
circuit breakers. As far as I am aware, the old fuse boxes (even when fuses
contained fuse wire) did what they were designed to do, with no problems.

They did what they were supposed to - and will still do so. The main
thing your current setup lacks is RCD protection.

My fuse box has circuit-breakers for:
Upstairs ring main
Downstairs ring main
Upstairs light circuit
Downstairs lighting circuit
Electric shower circuit
External security lights circuit

Obviously, I'd like to avoid the expense of updating it if I'm not under
any legal obligation to change anything. Is there really a significant
increase in electrical safety with the modern RCD units?

RCDs represent a significant improvement in safety. Especially if you
ever use electrical tools / appliances outside. The lack of RCD
protection would also make adding or extending your existing
installation in a compliant way more difficult, should you need to do so.

(some will argue that the chances of being killed by an electric shock
in the home in the UK is vanishingly small, and indeed they are correct.
However that misses the significant number of non fatal injuries per
year (200K hospital admissions), the vast majority of which would have
been prevented by a working RCD).

RCDs greatly shorten shock duration of L-E shocks. They don't act on L-N shocks.

I am not sure that makes sense... What is a L-E or L-N "shock"?

(or do you mean that a shock resulting from simultaneous connection
between L & N, while completely isolated from any independent earth
contact?)

Someone going to hospital because they got scared doesn't mean they're injured.

It does if they now have cardiac arrhythmia...

--
Cheers,

John.

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

On 22 Jun 2015 09:05:02 GMT, Jim x321x wrote:

wrote in
:

My house was built and wired in the 1980s and has an old-style fuse
box.

The old fuses have all been repeplaced with cirquit-breakers plugged
into

the fuse sockets.

There can be issues with doing this. Certain designs have gaps between
the MCBs and the cover which would fail modern ingress protection
rating against poking things in. Also the plug-in MCBs sometimes have
a lower breaking capacity than 'conventional' MCBs.

Thanks. I have to admit, that there *is*, arguably an issue with the
plastic cover that originally covered all the fuses. The subsequently-
installed MCBs stick out to far to allow the old cover to be attached. So I
simply left it off. My thinking was that MCBs should probably be in plain
view anyway, because one should be able to access them quickly. Also,
unenlightened tenenats and/or their guests might not know where the MCbs
are located if they were all covered with an opaque plastic cover that's
screwed on.

I suppose I could quite easily modify the cover to make it deep enough to
cover the MCBs without obstructing free flip-switch operation.

BTW, I am in England, so not bound by regional Scottish regulations.

Jim

I used to have a Wylex CU with the old style push button retrofit
MCBs.

The face of the cover had been removed so it just formed a frame
around the breakers. I don't remember if the original cover had been
modified, or if it was a special item supplied with the MCBs



--

Graham.

%Profound_observation%

On 22/06/2015 08:44, wrote:
On Monday, June 22, 2015 at 8:27:58 AM UTC+1, Andy Burns wrote:
Andy Burns wrote:

an RCBO requires additional contacts (neutral in and out and an
earth)

Which makes me ask another question ...
Why does an RCBO require a functional earth, when an RCD doesn't?

The earth connection enables the RCBO to trip even with a lost neutral connection.

You would need to refer to the manufacturers notes for the actual set of
conditions that are detectable by any given RCBO - they don't all work
the same.

Loss of neutral may be one (although of little relevance for anyone on a
TN supply in reality). It may also include things like detection of
supply polarity reversal (more uncommon), or the ability to detect a N
to E short in the absence of any current flow in the circuit.


--
Cheers,

John.

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| John Rumm - john(at)internode(dot)co(dot)uk |
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On Mon, 22 Jun 2015 15:36:58 +0100, John Rumm
wrote:

On 22/06/2015 12:52, Graham. wrote:
On Mon, 22 Jun 2015 10:54:02 +0100, John Rumm
wrote:

On 22/06/2015 09:06, Brian-Gaff wrote:
Well, I've never come across any rented property that has the very latest
fuse box/rcd. But that may just be coincidence. I do not go around checking
everyones houses I visit for rcds, only that a blind person can safely reach
the reset buttons!

Indeed - how would you cope with re-wireing a BS3036 style fuse?

I bet Brian could do that with no problem.
I bet you and I could do it blindfolded it we tried, I never have!

More than likely - but familiarity is the key (and knowing what you are
trying to achieve)

For an unskilled user attempting to identify the failed fuse, locate the
right rating of spare fuse wire, effecting the replacement and then
getting the fuse back into the CU - all in the dark, when you have never
even bother looking at the fuse box in the past, is quite a "big ask"!
Especially when compared to finding which MCB has tripped and flipping
the switch.

I've re spooled plenty of 35mm cassettes using a changing bag, and
loaded various film sizes into the spiral if a developing tank in
complete darkness.

Indeed, same here.

I always have a small pen knife in my pocket with a screwdriver that
would be adequate to rewire a wylex fuse as well. I suspect I am in the
minority though when it comes to preparedness for fuse re-wiring ;-)

Known as "Going equipped, in some circles ;-)


I'm not suggesting for a moment that a sighted person in the dark
equates to a blind person. That would indeed be arrogant.

I would expect a sighted person in the dark to perform substantially
less well than a blind one.

That was my intended inference.


--

Graham.

%Profound_observation%

On Mon, 22 Jun 2015 15:47:39 +0100, John Rumm
wrote:

On 22/06/2015 11:37, wrote:
On Monday, 22 June 2015 11:05:10 UTC+1, John Rumm wrote:
On 22/06/2015 09:56, Jim x321x wrote:
John Rumm wrote in
:

with the existing setup, and I rarely get any inexplicable
tripping of the circuit breakers. As far as I am aware, the
old fuse boxes (even when fuses contained fuse wire) did
what they were designed to do, with no problems.

They did what they were supposed to - and will still do so.
The main thing your current setup lacks is RCD protection.


Thanks to all for the excellently helpful advice.

If I added an RCD covering the entire house (without replacing
the existing fuse box which is already fitted with MCBs, would
that constitute a change to the wiring and thus require building
control notification?

Firstly you don't want a single RCD covering the whole house -
that is a practice that was common during the 15th edition, but is
deprecated now since it offers no "discrimination" in the event of
a fault (i.e. the fault will take out the supply to the whole
house, not just the circuit causing the problem). So many circuits
on one RCD are also more prone to nuisance tripping in the first
place.

A single RCD is moderately likely to not even work.

True, but the failure rate is not high enough to make that relevant I
would say. (IIRC, 15% of those that have never been tested may fail to
operate when they should - but that sill leaves 75% that will work and
potentially prevent an injury)

I don't see that as a failure rate, just additional work to be done to
rectify the earth leakage faults that may have unknowingly have been
present for decades.

Not that I'm saying a whole house RCD was ever the ideal solution.





--

Graham.

%Profound_observation%

On Mon, 22 Jun 2015 15:55:24 +0100, John Rumm
wrote:

On 22/06/2015 11:28, wrote:
On Monday, 22 June 2015 04:51:01 UTC+1, John Rumm wrote:
On 21/06/2015 23:20, Jim x321x wrote:

My house was built and wired in the 1980s and has an old-style fuse box.
The old fuses have all been repeplaced with cirquit-breakers plugged into
the fuse sockets. A couple of people, such as estate agents and
electricians have raised eyebrows on seeing the box, telling me it should
be changed for a modern RCD unit. Is this true? I've never had any problems

There is no legal requirement to change it.

with the existing setup, and I rarely get any inexplicable tripping of the
circuit breakers. As far as I am aware, the old fuse boxes (even when fuses
contained fuse wire) did what they were designed to do, with no problems.

They did what they were supposed to - and will still do so. The main
thing your current setup lacks is RCD protection.

My fuse box has circuit-breakers for:
Upstairs ring main
Downstairs ring main
Upstairs light circuit
Downstairs lighting circuit
Electric shower circuit
External security lights circuit

Obviously, I'd like to avoid the expense of updating it if I'm not under
any legal obligation to change anything. Is there really a significant
increase in electrical safety with the modern RCD units?

RCDs represent a significant improvement in safety. Especially if you
ever use electrical tools / appliances outside. The lack of RCD
protection would also make adding or extending your existing
installation in a compliant way more difficult, should you need to do so.

(some will argue that the chances of being killed by an electric shock
in the home in the UK is vanishingly small, and indeed they are correct.
However that misses the significant number of non fatal injuries per
year (200K hospital admissions), the vast majority of which would have
been prevented by a working RCD).

RCDs greatly shorten shock duration of L-E shocks. They don't act on L-N shocks.

I am not sure that makes sense... What is a L-E or L-N "shock"?

(or do you mean that a shock resulting from simultaneous connection
between L & N, while completely isolated from any independent earth
contact?)

Someone going to hospital because they got scared doesn't mean they're injured.

It does if they now have cardiac arrhythmia...

....Nothing another ZAP won't cure (allegedly).

--

Graham.

%Profound_observation%

On 22/06/2015 16:07, Graham. wrote:
On Mon, 22 Jun 2015 15:36:58 +0100, John Rumm
wrote:

On 22/06/2015 12:52, Graham. wrote:
On Mon, 22 Jun 2015 10:54:02 +0100, John Rumm
wrote:

On 22/06/2015 09:06, Brian-Gaff wrote:
Well, I've never come across any rented property that has the very latest
fuse box/rcd. But that may just be coincidence. I do not go around checking
everyones houses I visit for rcds, only that a blind person can safely reach
the reset buttons!

Indeed - how would you cope with re-wireing a BS3036 style fuse?

I bet Brian could do that with no problem.
I bet you and I could do it blindfolded it we tried, I never have!

More than likely - but familiarity is the key (and knowing what you are
trying to achieve)

For an unskilled user attempting to identify the failed fuse, locate the
right rating of spare fuse wire, effecting the replacement and then
getting the fuse back into the CU - all in the dark, when you have never
even bother looking at the fuse box in the past, is quite a "big ask"!
Especially when compared to finding which MCB has tripped and flipping
the switch.

I've re spooled plenty of 35mm cassettes using a changing bag, and
loaded various film sizes into the spiral if a developing tank in
complete darkness.

Indeed, same here.

I always have a small pen knife in my pocket with a screwdriver that
would be adequate to rewire a wylex fuse as well. I suspect I am in the
minority though when it comes to preparedness for fuse re-wiring ;-)

Known as "Going equipped, in some circles ;-)

Its main blade is about an inch long - I could do you more damage with a
hard stare! ;-)

I'm not suggesting for a moment that a sighted person in the dark
equates to a blind person. That would indeed be arrogant.

I would expect a sighted person in the dark to perform substantially
less well than a blind one.

That was my intended inference.


--
Cheers,

John.

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

GB wrote in :

(some will argue that the chances of being killed by an electric shock
in the home in the UK is vanishingly small,

About the same as the chance of winning the lottery (give or take a
factor of 10), yet many people buy lottery tickets.


Given a choice of the two, I'd probably opt for the lotter win.

Al

Graham. wrote in newsb8goalbvo9ptee6d1njgjotrlv5snr5um@
4ax.com:

I used to have a Wylex CU with the old style push button retrofit
MCBs.

The face of the cover had been removed so it just formed a frame
around the breakers. I don't remember if the original cover had been
modified, or if it was a special item supplied with the MCBs



That sounds like a good idea. That would stop say, a toddler from poking a
knife past the back of the MCB and barbequing himself, wouldn't it? I might
do that myself. (Cut the face off the cover, and then fix the remaining
part where it was intended to be.)

Jim