Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.

--

Jeff

On Sunday, 20 September 2020 at 09:11:47 UTC+1, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.

--

Jeff

I rewired a house in 1983 and certainly there was no such wiring, the recommendation at the time was to to have separate ring mains and lighting circuits upstairs and down. I have seen instances where people have wired spurs off an upstairs ring into a room below which has safety implications. It can be a common mistake in houses which have solid floors downstairs as it is possible to have two ring mains running in the ceiling space one providing drop feeds to the downstairs and the other for the upstairs, maybe something like that has occurred at your friends house?

Richard

It does indeed seem odd if, in effect there is now one circuit and two
breakers across each other for them both.
I guess isolation of the circuits and a long laborious process of checking
sockets is the only way to find this, unless there is evidence of work
having been done somewhere where the effect might have been caused. Mighty
weird. Mine was done in 1975, and there are two circuits on both lights and
sockets, plus one for a higher current feed for a cooker and a separate one
for the Immersion heater on its own. I also now have a special one for
Economy 7 with a higher current rating only live in the hours needed.
Brian

--
--
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Tricky Dicky" wrote in message
...
On Sunday, 20 September 2020 at 09:11:47 UTC+1, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.

--

Jeff

I rewired a house in 1983 and certainly there was no such wiring, the
recommendation at the time was to to have separate ring mains and lighting
circuits upstairs and down. I have seen instances where people have wired
spurs off an upstairs ring into a room below which has safety implications.
It can be a common mistake in houses which have solid floors downstairs as
it is possible to have two ring mains running in the ceiling space one
providing drop feeds to the downstairs and the other for the upstairs, maybe
something like that has occurred at your friends house?

Richard

On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.



There were never two MCBs .

It seems that the ring is supplied from two MCBs.

This could be like the ones I have seen where the immersion 2.5 was in
the 32A sockets MCB with one leg of the ring and the other leg of the
ring was in the immersion 16A MCB.

Or even worse was the two rings (up sockets and down sockets) with one
leg of up sockets and one leg of the down sockets in one MCB and the
other legs in another MCB.

--
Adam

Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.

Our house (as in the house I grew up in, back in the 1950s) had a very
early ring circuit as it was built in 1949 or thereabouts. It
definitely had fuses at each end of the ring. Whether that was as it
should have been or just how the electrician (my father I think)
thought it should be I don't know.

--
Chris Green
·

On 20/09/2020 09:43, Tricky Dicky wrote:


I have seen instances where people have wired spurs off an upstairs ring into a room below which has safety implications.

I would say that does not break any regs if the CU is labelled up correctly.


--
Adam

On Sunday, 20 September 2020 10:48:07 UTC+1, Chris Green wrote:
Our house (as in the house I grew up in, back in the 1950s) had a very
early ring circuit as it was built in 1949 or thereabouts. It
definitely had fuses at each end of the ring. Whether that was as it
should have been or just how the electrician (my father I think)
thought it should be I don't know.

When rings were first introduced, people used to make them from 2 15A radial circuits joined together.

I don't know how officially-sanctioned that was or for how long.

Owain

Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.


I suspect he just means that he switched off the ring supply MCB for that
area/floor and the RCD protection (which may cover all circuits) as well.

Tim

--
Please don't feed the trolls

On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.


The same thing ocurred in a house i owned in the 1980's built about 10
yrs before.

I too found the 13A ring mains were connected to two 30A fuses in the CU.

I of course corrected it to have each ring main wired in to one 30A fuse.

On dicussing the matter with each of my adjacent neighbours, it turned
out they both had the same problem!

On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.


Sounds to me as if someone has at some time added a loop with additional
socket(s) and has connected one end to one ring and the other end to
another ring - thus cross-connecting the rings. Somewhat undesirable!
--
Cheers,
Roger

On 20/09/2020 11:27, Jack Harry Teesdale wrote:
On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.


The same thing ocurred in a house i owned in the 1980's built about 10
yrs before.

I too found the 13A ring mains were connected to two 30A fuses in the CU.

I of course corrected it to have each ring main wired in to one 30A fuse.

On dicussing the matter with each of my adjacent neighbours, it turned
out they both had the same problem!

Interesting. I forgot to add that I asked my friend if he could check
with other houses nearby on the estate to see if they had the same
wiring as he found.

--

Jeff

wrote:
On Sunday, 20 September 2020 10:48:07 UTC+1, Chris Green wrote:
Our house (as in the house I grew up in, back in the 1950s) had a very
early ring circuit as it was built in 1949 or thereabouts. It
definitely had fuses at each end of the ring. Whether that was as it
should have been or just how the electrician (my father I think)
thought it should be I don't know.

When rings were first introduced, people used to make them from 2 15A radial
circuits joined together.

Ah, but this was a new house with new electrics, all the new fangled
square pin fused plugs etc.

I don't know how officially-sanctioned that was or for how long.

Owain


--
Chris Green
·

On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.

Not in the 80's...

There was a time when the ring circuit was first introduced in the 40's
that it may have been formed from two 15A fused radials, that were
joined in the middle so to speak. It was a way of creating a more
versatile circuit that could be used for house heating etc, at a time
(i.e. just after WWII) when materials were in short supply.

So in summary, he has some faulty wiring.

--
Cheers,

John.

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

In article ,
wrote:
On Sunday, 20 September 2020 10:48:07 UTC+1, Chris Green wrote:
Our house (as in the house I grew up in, back in the 1950s) had a very
early ring circuit as it was built in 1949 or thereabouts. It
definitely had fuses at each end of the ring. Whether that was as it
should have been or just how the electrician (my father I think)
thought it should be I don't know.

When rings were first introduced, people used to make them from 2 15A
radial circuits joined together.

I don't know how officially-sanctioned that was or for how long.

Yes- I've seen that several times, with old style fuseboxes. I suppose
it's safe enough as regards circuit protection?

--
*Why is it that to stop Windows 95, you have to click on "Start"?

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

On 20/09/2020 09:11:41, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.

I can see the logic, where the two MCBs are each rated for 2.5mm cable
which will allow more current be safely pulled along the ring.

I wonder if it will catch on?

Obviously you would need a common RCD.

On 21/09/2020 00:08, Fredxx wrote:
On 20/09/2020 09:11:41, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket
in our lounge with a switched double. In order to stop the supply, I
had to switch off two trip switches at the same time." That didn't
sound right, or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in
all modern rings...". Does that mean there might have been two fuses
or MCBs in early rings? I think his house was built around 1980.

I can see the logic, where the two MCBs are each rated for 2.5mm cable
which will allow more current be safely pulled along the ring.

I wonder if it will catch on?






Obviously you would need a common RCD.

Actually you do not as there will be no imbalance between live and neutral.



--
Adam

On 21/09/2020 04:02:32, ARW wrote:
On 21/09/2020 00:08, Fredxx wrote:
On 20/09/2020 09:11:41, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket
in our lounge with a switched double. In order to stop the supply, I
had to switch off two trip switches at the same time." That didn't
sound right, or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in
all modern rings...". Does that mean there might have been two fuses
or MCBs in early rings? I think his house was built around 1980.

I can see the logic, where the two MCBs are each rated for 2.5mm cable
which will allow more current be safely pulled along the ring.

I wonder if it will catch on?






Obviously you would need a common RCD.

Actually you do not as there will be no imbalance between live and neutral.

Any imbalance (leakage to earth) would be shared between the two RCDs,
assuming they are identical. So the residual current would be close to
twice the expected value before one tripped. The other would follow
immediately.

On 20/09/2020 09:43, Tricky Dicky wrote:

I rewired a house in 1983 and certainly there was no such wiring, the recommendation at the time was to to have separate ring mains and lighting circuits upstairs and down. I have seen instances where people have wired spurs off an upstairs ring into a room below which has safety implications. It can be a common mistake in houses which have solid floors downstairs as it is possible to have two ring mains running in the ceiling space one providing drop feeds to the downstairs and the other for the upstairs, maybe something like that has occurred at your friends house?


My house has left/right ring mains rather than up/down. Some rooms, like
the hall, have both ring mains. It's often quite useful, easier to run
an extension lead from rooms on the same floor than it is down the stairs.

Is this against the regs/ a mistake?

It did confuse me a couple of days ago, but more that I switched off
something I didn't mean to, rather than I mistakenly left a socket live.
I always physically check a socket isn't live before working on it.

On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

My friend just replied. He thinks that the problem must have occurred
when the new CU and the new wiring in the extension were joined up to
the original house wiring, 18 years ago.

Out of interest, anyone know if this was out of line with Part P then?
For that matter, is it out of line with Part P now? I would have thought
it was out-of-line as it represents a shock hazard - although an unusual
one.

--

Jeff

On 21 Sep 2020 at 13:51:23 BST, "jeff Layman" wrote:

On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

My friend just replied. He thinks that the problem must have occurred
when the new CU and the new wiring in the extension were joined up to
the original house wiring, 18 years ago.

Out of interest, anyone know if this was out of line with Part P then?
For that matter, is it out of line with Part P now? I would have thought
it was out-of-line as it represents a shock hazard - although an unusual
one.

If either of the MCBs that feed the offending socket have more than one wire
going into them then it definitely needs fixing. It may or may not be
actually dangerous, but someone needs to check.

--
Roger Hayter

In article ,
jeff Layman wrote:
On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

My friend just replied. He thinks that the problem must have occurred
when the new CU and the new wiring in the extension were joined up to
the original house wiring, 18 years ago.

Out of interest, anyone know if this was out of line with Part P then?
For that matter, is it out of line with Part P now? I would have thought
it was out-of-line as it represents a shock hazard - although an unusual
one.

was there a Part P 18 years ago?

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 21/09/2020 16:29, charles wrote:
In article ,
jeff Layman wrote:
On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

My friend just replied. He thinks that the problem must have occurred
when the new CU and the new wiring in the extension were joined up to
the original house wiring, 18 years ago.

Out of interest, anyone know if this was out of line with Part P then?
For that matter, is it out of line with Part P now? I would have thought
it was out-of-line as it represents a shock hazard - although an unusual
one.

was there a Part P 18 years ago?

Probably. There was a Part P in 2013 from the Building Regs of 2010. The
2013 Part P states:
"This approved document supports Part P: Electrical safety €“ Dwellings.
It takes effect on 6 April 2013 and is for use in England. The 2006
edition will continue to apply to work begun before 6 April 2013, or to
work subject to a building notice, full plans application or initial
notice submitted before 6 April 2013."

That says there was one in 2006, so I guess there might well have been
one in 2002.

--

Jeff

On 21/09/2020 16:29, charles wrote:
In article ,
jeff Layman wrote:
On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

My friend just replied. He thinks that the problem must have occurred
when the new CU and the new wiring in the extension were joined up to
the original house wiring, 18 years ago.

Out of interest, anyone know if this was out of line with Part P then?
For that matter, is it out of line with Part P now? I would have thought
it was out-of-line as it represents a shock hazard - although an unusual
one.

was there a Part P 18 years ago?

Nope, it was first proposed in 2005, the first approved document being
the 2006 version. The scope would also have excluded any jobs already
underway when it came into effect.




--
Cheers,

John.

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

On 21/09/2020 04:07, Fredxx wrote:
On 21/09/2020 04:02:32, ARW wrote:
On 21/09/2020 00:08, Fredxx wrote:
On 20/09/2020 09:11:41, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket
in our lounge with a switched double. In order to stop the supply, I
had to switch off two trip switches at the same time." That didn't
sound right, or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in
all modern rings...". Does that mean there might have been two fuses
or MCBs in early rings? I think his house was built around 1980.

I can see the logic, where the two MCBs are each rated for 2.5mm
cable which will allow more current be safely pulled along the ring.

I wonder if it will catch on?






Obviously you would need a common RCD.

Actually you do not as there will be no imbalance between live and
neutral.

Any imbalance (leakage to earth) would be shared between the two RCDs,
assuming they are identical. So the residual current would be close to
twice the expected value before one tripped. The other would follow
immediately.



Yes. Agreed.

I was making the point that if you put one end of a ring into one RCD
and the other end into another RCD the circuit would work (if there are
no faults).

Cheers

--
Adam

charles wrote:

was there a Part P 18 years ago?

No, it came in on 1/1/2005

I have twice now come across the arrangement where instead of a 30A/32A
fuse/breaker a ring has been wired from a 15A/16A around the property
and back to another 15A/16A. That sort-a gives a 30A ring but only
sort of.

I discovered it in my current flat over the summer when I was inserting
a socket into the ring in the roof space. After checking everything I
swapped it for a single 32A breaker. This in a consumer unit with a label
claiming the installation had been checked in 2015, just before I moved
in and when the flat was refurbished.

jgh

On 21/09/2020 10:27, Pancho wrote:
On 20/09/2020 09:43, Tricky Dicky wrote:

I rewired a house in 1983 and certainly there was no such wiring, the
recommendation at the time was to to have separate ring mains and
lighting circuits upstairs and down. I have seen instances where
people have wired spurs off an upstairs ring into a room below which
has safety implications. It can be a common mistake in houses which
have solid floors downstairs as it is possible to have two ring mains
running in the ceiling space one providing drop feeds to the
downstairs and the other for the upstairs, maybe something like that
has occurred at your friends house?


My house has left/right ring mains rather than up/down. Some rooms, like
the hall, have both ring mains. It's often quite useful, easier to run
an extension lead from rooms on the same floor than it is down the stairs.

Is this against the regs/ a mistake?

It did confuse me a couple of days ago, but more that I switched off
something I didn't mean to, rather than I mistakenly left a socket live.
I always physically check a socket isn't live before working on it.


I have something similar here but with 6 ring mains:

Kitchen & Utility room

Front room and the bedroom above it and the office above the kitchen and
the landing sockets

Dining room and the bedroom above it

Lounge and the Master bedroom above it and hall sockets

Loft ring main

Garage sockets and all outside sockets

On 20/09/2020 10:45, ARW wrote:
On 20/09/2020 09:43, Tricky Dicky wrote:


I have seen instances where people have wired spurs off an upstairs
ring into a room below which has safety implications.

I would say that does not break any regs if the CU is labelled up
correctly.



All the houses on the estate where I live were built between 1972
and 1976 and the 2 and 3 bed semis and terraces only have one ring
main for the whole house, plus cooker and immersion feeds, but have
separate lighting spurs for upstairs and downstairs (with borrowed
neutral on 2-way stairs/landing switching).

On 21/09/2020 17:17, Jeff Layman wrote:
On 21/09/2020 16:29, charles wrote:
In article ,
Â*Â*Â* jeff Layman wrote:
On 20/09/2020 09:11, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I
had to
switch off two trip switches at the same time." That didn't sound
right,
or safe.

My friend just replied. He thinks that the problem must have occurred
when the new CUÂ* and the new wiring in the extension were joined up to
the original house wiring, 18 years ago.

Out of interest, anyone know if this was out of line with Part P then?
For that matter, is it out of line with Part P now? I would have thought
it was out-of-line as it represents a shock hazard - although an unusual
one.

was there a Part P 18 years ago?

Probably. There was a Part P in 2013 from the Building Regs of 2010. The
2013 Part P states:
"This approved document supports Part P: Electrical safety €“ Dwellings.
It takes effect on 6 April 2013 and is for use in England. The 2006
edition will continue to apply to work begun before 6 April 2013, or to
work subject to a building notice, full plans application or initial
notice submitted before 6 April 2013."

That says there was one in 2006, so I guess there might well have been
one in 2002.



I thought Part P commenced on jan 1st 2005 ?, though the harmonised
cable colours were on sale before then.

On Sunday, 20 September 2020 09:43:25 UTC+1, Tricky Dicky wrote:
On Sunday, 20 September 2020 at 09:11:47 UTC+1, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket in
our lounge with a switched double. In order to stop the supply, I had to
switch off two trip switches at the same time." That didn't sound right,
or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in all
modern rings...". Does that mean there might have been two fuses or MCBs
in early rings? I think his house was built around 1980.

If you read the link you gave you'd have the answer to your question


I rewired a house in 1983 and certainly there was no such wiring, the recommendation at the time was to to have separate ring mains and lighting circuits upstairs and down. I have seen instances where people have wired spurs off an upstairs ring into a room below which has safety implications. It can be a common mistake in houses which have solid floors downstairs as it is possible to have two ring mains running in the ceiling space one providing drop feeds to the downstairs and the other for the upstairs, maybe something like that has occurred at your friends house?

Richard

it's not a mistake & doesn't have safety implications.


NT

On Sunday, 20 September 2020 10:54:40 UTC+1, wrote:
On Sunday, 20 September 2020 10:48:07 UTC+1, Chris Green wrote:

Our house (as in the house I grew up in, back in the 1950s) had a very
early ring circuit as it was built in 1949 or thereabouts. It
definitely had fuses at each end of the ring. Whether that was as it
should have been or just how the electrician (my father I think)
thought it should be I don't know.

When rings were first introduced, people used to make them from 2 15A radial circuits joined together.

I don't know how officially-sanctioned that was or for how long.

Owain

It was part of the original rationale for the design.


NT

On Monday, 21 September 2020 04:07:20 UTC+1, Fredxx wrote:
On 21/09/2020 04:02:32, ARW wrote:
On 21/09/2020 00:08, Fredxx wrote:
On 20/09/2020 09:11:41, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket
in our lounge with a switched double. In order to stop the supply, I
had to switch off two trip switches at the same time." That didn't
sound right, or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in
all modern rings...". Does that mean there might have been two fuses
or MCBs in early rings? I think his house was built around 1980.

I can see the logic, where the two MCBs are each rated for 2.5mm cable
which will allow more current be safely pulled along the ring.

I wonder if it will catch on?






Obviously you would need a common RCD.

Actually you do not as there will be no imbalance between live and neutral.

Any imbalance (leakage to earth) would be shared between the two RCDs,
assuming they are identical. So the residual current would be close to
twice the expected value before one tripped. The other would follow
immediately.

Any slightly high R joint would result in imbalance & trip the RCDs.


NT

Andrew wrote:

I thought Part P commenced on jan 1st 2005 ?

It did, I fitted my consumer unit on dec 31st 2004.

though the harmonised cable colours were on sale before then.

They were.

On 24/09/2020 11:29, Andrew wrote:
On 21/09/2020 17:17, Jeff Layman wrote:

Probably. There was a Part P in 2013 from the Building Regs of 2010.
The 2013 Part P states:
"This approved document supports Part P: Electrical safety €“
Dwellings. It takes effect on 6 April 2013 and is for use in England.
The 2006 edition will continue to apply to work begun before 6 April
2013, or to work subject to a building notice, full plans application
or initial notice submitted before 6 April 2013."

That says there was one in 2006, so I guess there might well have been
one in 2002.



I thought Part P commenced on jan 1st 2005 ?, though the harmonised
cable colours were on sale before then.

Yup, new colours were permitted before part P and old colours still
permitted after it. So, contrary to popular opinion, the colours tell
you nothing definitive for dating an install (wrt part P anyway).


--
Cheers,

John.

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

On 24/09/2020 12:15, wrote:
On Sunday, 20 September 2020 10:54:40 UTC+1, wrote:
On Sunday, 20 September 2020 10:48:07 UTC+1, Chris Green wrote:

Our house (as in the house I grew up in, back in the 1950s) had a very
early ring circuit as it was built in 1949 or thereabouts. It
definitely had fuses at each end of the ring. Whether that was as it
should have been or just how the electrician (my father I think)
thought it should be I don't know.

When rings were first introduced, people used to make them from 2 15A radial circuits joined together.

I don't know how officially-sanctioned that was or for how long.

It was part of the original rationale for the design.

Was each circuit fused for the whole ring, or half?

--
Max Demian

On Thursday, 24 September 2020 17:24:20 UTC+1, Max Demian wrote:
On 24/09/2020 12:15, tabbypurr wrote:
On Sunday, 20 September 2020 10:54:40 UTC+1, wrote:
On Sunday, 20 September 2020 10:48:07 UTC+1, Chris Green wrote:

Our house (as in the house I grew up in, back in the 1950s) had a very
early ring circuit as it was built in 1949 or thereabouts. It
definitely had fuses at each end of the ring. Whether that was as it
should have been or just how the electrician (my father I think)
thought it should be I don't know.

When rings were first introduced, people used to make them from 2 15A radial circuits joined together.

I don't know how officially-sanctioned that was or for how long.

It was part of the original rationale for the design.

Was each circuit fused for the whole ring, or half?

2x 15A fuses running a 30A ring. The point was one could add unlimited extra sockets by joining 2x existing 15A socket circuits into a ring. It was an ingenious solution combining cost cutting with safety improvement.

The link given also explains the 4 fuse variant.


NT

On 24/09/2020 21:48, wrote:
On Thursday, 24 September 2020 17:24:20 UTC+1, Max Demian wrote:
On 24/09/2020 12:15, tabbypurr wrote:
On Sunday, 20 September 2020 10:54:40 UTC+1, wrote:
On Sunday, 20 September 2020 10:48:07 UTC+1, Chris Green wrote:

Our house (as in the house I grew up in, back in the 1950s) had a very
early ring circuit as it was built in 1949 or thereabouts. It
definitely had fuses at each end of the ring. Whether that was as it
should have been or just how the electrician (my father I think)
thought it should be I don't know.

When rings were first introduced, people used to make them from 2 15A radial circuits joined together.

I don't know how officially-sanctioned that was or for how long.

It was part of the original rationale for the design.

Was each circuit fused for the whole ring, or half?

2x 15A fuses running a 30A ring. The point was one could add unlimited extra sockets by joining 2x existing 15A socket circuits into a ring. It was an ingenious solution combining cost cutting with safety improvement.

What if you plugged two 3kW fires into sockets near one of the fuses?
wouldn't it blow, or at least overheat the nearest fuse? A proper ring
main would cope easily with a single 32A fuse.


--
Max Demian

On 24/09/2020 12:18, wrote:
On Monday, 21 September 2020 04:07:20 UTC+1, Fredxx wrote:
On 21/09/2020 04:02:32, ARW wrote:
On 21/09/2020 00:08, Fredxx wrote:
On 20/09/2020 09:11:41, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket
in our lounge with a switched double. In order to stop the supply, I
had to switch off two trip switches at the same time." That didn't
sound right, or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in
all modern rings...". Does that mean there might have been two fuses
or MCBs in early rings? I think his house was built around 1980.

I can see the logic, where the two MCBs are each rated for 2.5mm cable
which will allow more current be safely pulled along the ring.

I wonder if it will catch on?






Obviously you would need a common RCD.

Actually you do not as there will be no imbalance between live and neutral.

Any imbalance (leakage to earth) would be shared between the two RCDs,
assuming they are identical. So the residual current would be close to
twice the expected value before one tripped. The other would follow
immediately.

Any slightly high R joint would result in imbalance & trip the RCDs.



This was covered a few years ago.


--
Adam

On 25/09/2020 19:33, ARW wrote:
On 24/09/2020 12:18, wrote:
On Monday, 21 September 2020 04:07:20 UTC+1, FredxxÂ* wrote:
On 21/09/2020 04:02:32, ARW wrote:
On 21/09/2020 00:08, Fredxx wrote:
On 20/09/2020 09:11:41, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket
in our lounge with a switched double. In order to stop the supply, I
had to switch off two trip switches at the same time." That didn't
sound right, or safe.

DIYWiki notes: at
(http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]),
visits
each socket in turn, and then returns to the consumer unit. The 2
cable
ends at the CU are connected together in all modern rings, and
supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in
all modern rings...". Does that mean there might have been two fuses
or MCBs in early rings? I think his house was built around 1980.

I can see the logic, where the two MCBs are each rated for 2.5mm cable
which will allow more current be safely pulled along the ring.

I wonder if it will catch on?






Obviously you would need a common RCD.

Actually you do not as there will be no imbalance between live and
neutral.

Any imbalance (leakage to earth) would be shared between the two RCDs,
assuming they are identical. So the residual current would be close to
twice the expected value before one tripped. The other would follow
immediately.

Any slightly high R joint would result in imbalance & trip the RCDs.



This was covered a few years ago.

Ah, the famous dennis never ending wriggling thread?

2012 by the looks of it! :

https://groups.google.com/g/uk.d-i-y...m/b5UnByn9pIcJ


--
Cheers,

John.

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

On 24/09/2020 12:18:05, wrote:
On Monday, 21 September 2020 04:07:20 UTC+1, Fredxx wrote:
On 21/09/2020 04:02:32, ARW wrote:
On 21/09/2020 00:08, Fredxx wrote:
On 20/09/2020 09:11:41, Jeff Layman wrote:
Fortunately not mine!

A friend just told me "I have just replaced a single electric socket
in our lounge with a switched double. In order to stop the supply, I
had to switch off two trip switches at the same time." That didn't
sound right, or safe.

DIYWiki notes: at (http://wiki.diyfaq.org.uk/index.php/Ring_circuit):
"The ring circuit cable starts at the consumer unit (fusebox]), visits
each socket in turn, and then returns to the consumer unit. The 2 cable
ends at the CU are connected together in all modern rings, and supplied
by one fuse or MCB."

That confirms there should be one MCB, but I note the use of "...in
all modern rings...". Does that mean there might have been two fuses
or MCBs in early rings? I think his house was built around 1980.

I can see the logic, where the two MCBs are each rated for 2.5mm cable
which will allow more current be safely pulled along the ring.

I wonder if it will catch on?






Obviously you would need a common RCD.

Actually you do not as there will be no imbalance between live and neutral.

Any imbalance (leakage to earth) would be shared between the two RCDs,
assuming they are identical. So the residual current would be close to
twice the expected value before one tripped. The other would follow
immediately.

Any slightly high R joint would result in imbalance & trip the RCDs.

I have to say was my thought. Worst case scenario would be live fed
through RCD and neutral fed through the other RCD.

Both would see an imbalance equal to the current drawn by the load.