Fred wrote:

It seems that shaver sockets with an isolating transformer can be
connected in the bathroom to the ring main via a FCU but as the ring
is often not available the more common approach is to connect it to
the light radial, where a FCU is not necessary but some people chose
to fit them for isolation purposes.

So far so good. However the supply earth to the shaver socket needs to
be bonded and this is where I begin to get confused.

What supply earth to the shaver socket? It's a two pin plug - no earth.

Hi,

My newserver has a lot of old posts made here about shaver sockets and
I have tried to read them all.

It seems that shaver sockets with an isolating transformer can be
connected in the bathroom to the ring main via a FCU but as the ring
is often not available the more common approach is to connect it to
the light radial, where a FCU is not necessary but some people chose
to fit them for isolation purposes.

So far so good. However the supply earth to the shaver socket needs to
be bonded and this is where I begin to get confused. My questions a

What size cpc do you use? Some posts suggested big fat earth cable
(10mm^2, 16mm^2?), whereas others said the cpc of the T&E would be
fine. Which is right?

The bath, radiators, and basin taps are bonded with "big fat" earth
cable as far as I can see. I don't know where the cable runs under
the floorboards so I don't know whether it stays in the bathroom only,
or whether it goes back to the CU. This would have been done some time
ago, so possibly is not up to the current regs? Also some of the
copper pipe would have been replaced with plastic since then, so it
could probably do with someone having a look at it all.

Where do you connect the earth from the light radial to everything
else? Some posts suggested that if they both ran back to the CU's
earth bar, that would be fine, but other posts seemed to contradict
this and suggest it had to be done locally. Having a yellow and green
cable down the wall would not look pretty imho. I am pretty sure that
my light is not earth bonded at the moment so if I had a socket, this
would have to be done. Does it need doing even if I don't have a
socket fitted?

TIA

Fred wrote:
Hi,

My newserver has a lot of old posts made here about shaver sockets and
I have tried to read them all.

It seems that shaver sockets with an isolating transformer can be
connected in the bathroom to the ring main via a FCU but as the ring
is often not available the more common approach is to connect it to
the light radial, where a FCU is not necessary but some people chose
to fit them for isolation purposes.

So far so good. However the supply earth to the shaver socket needs to
be bonded and this is where I begin to get confused. My questions a

What size cpc do you use? Some posts suggested big fat earth cable
(10mm^2, 16mm^2?), whereas others said the cpc of the T&E would be
fine. Which is right?

It would be 4mm^2 cable OR the cpc. You would use 4mm^2 cable between the
hot and cold pipes, the bath (if metal), the radiator and to the cpc of
every electrical circuit in the bathroom. However this is where the cpc
comes into play. You would typically have a pull switch and a light in the
bathroom. You would not need to run a 4mm cable between the two - the cpc
will act as the bonding between the light and the switch. The same will
apply to your shaver socket if it is supplied from the lighting circuit -
the cpc will act as the bonding provided the lighting circuit is
supplementary bonded.

The bonding needs to be attatched to the cpc of each seperate electrical
circuit that enters the bathroom - eg if you also have an electric shower
that would need to be bonded.

The bath, radiators, and basin taps are bonded with "big fat" earth
cable as far as I can see. I don't know where the cable runs under
the floorboards so I don't know whether it stays in the bathroom only,
or whether it goes back to the CU.

Supplementary bonding need not run back to the CU.


Where do you connect the earth from the light radial to everything
else? Some posts suggested that if they both ran back to the CU's
earth bar, that would be fine, but other posts seemed to contradict
this and suggest it had to be done locally. Having a yellow and green
cable down the wall would not look pretty imho. I am pretty sure that
my light is not earth bonded at the moment so if I had a socket, this
would have to be done. Does it need doing even if I don't have a
socket fitted?

The usual method is to run a 4mm under the floorboards from the bathroom and
up the airing cupboard to the bathroom light. Easier said than done.

How are you going to run the 1mm T&E down to your shaver socket without it
looking as ugly as a green/yellow wire running down the wall?

Cheers

--
Adam

Ronald Raygun wrote:
Fred wrote:

It seems that shaver sockets with an isolating transformer can be
connected in the bathroom to the ring main via a FCU but as the ring
is often not available the more common approach is to connect it to
the light radial, where a FCU is not necessary but some people chose
to fit them for isolation purposes.

So far so good. However the supply earth to the shaver socket needs
to be bonded and this is where I begin to get confused.

What supply earth to the shaver socket? It's a two pin plug - no
earth.

?????????????
--
Adam

ARWadsworth wrote:

Ronald Raygun wrote:
Fred wrote:

It seems that shaver sockets with an isolating transformer can be
connected in the bathroom to the ring main via a FCU but as the ring
is often not available the more common approach is to connect it to
the light radial, where a FCU is not necessary but some people chose
to fit them for isolation purposes.

So far so good. However the supply earth to the shaver socket needs
to be bonded and this is where I begin to get confused.

What supply earth to the shaver socket? It's a two pin plug - no
earth.

?????????????

What I meant was that there are only two wires to the shaver socket,
to engage with the two pins on the shaver plug. Neither of the two
wires/contacts is ever live relative to earth because they are coming
from a transformer and so both should have high impedance to mains.
There are usually no other metal parts on a shaver socket (are there?) and
so no earthing is required (for the same reason the shaver flex is
2-conductor earthless despite the shaver itself having metal parts).

"Ronald Raygun" wrote in message
...
ARWadsworth wrote:

Ronald Raygun wrote:
Fred wrote:

It seems that shaver sockets with an isolating transformer can be
connected in the bathroom to the ring main via a FCU but as the ring
is often not available the more common approach is to connect it to
the light radial, where a FCU is not necessary but some people chose
to fit them for isolation purposes.

So far so good. However the supply earth to the shaver socket needs
to be bonded and this is where I begin to get confused.

What supply earth to the shaver socket? It's a two pin plug - no
earth.

?????????????

What I meant was that there are only two wires to the shaver socket,
to engage with the two pins on the shaver plug. Neither of the two
wires/contacts is ever live relative to earth because they are coming
from a transformer and so both should have high impedance to mains.
There are usually no other metal parts on a shaver socket (are there?) and
so no earthing is required (for the same reason the shaver flex is
2-conductor earthless despite the shaver itself having metal parts).



I've heard it all now!!!

Tim.

Tim.. wrote:
"Ronald Raygun" wrote in message
...
ARWadsworth wrote:

Ronald Raygun wrote:
Fred wrote:

It seems that shaver sockets with an isolating transformer can be
connected in the bathroom to the ring main via a FCU but as the
ring is often not available the more common approach is to
connect it to the light radial, where a FCU is not necessary but
some people chose to fit them for isolation purposes.

So far so good. However the supply earth to the shaver socket
needs to be bonded and this is where I begin to get confused.

What supply earth to the shaver socket? It's a two pin plug - no
earth.

?????????????

What I meant was that there are only two wires to the shaver socket,
to engage with the two pins on the shaver plug. Neither of the two
wires/contacts is ever live relative to earth because they are coming
from a transformer and so both should have high impedance to mains.
There are usually no other metal parts on a shaver socket (are
there?) and so no earthing is required (for the same reason the
shaver flex is 2-conductor earthless despite the shaver itself
having metal parts).


I've heard it all now!!!

Tim.


Are you not going to give Jerry and Harry their say before jumping to that
conclusion:-)?


--
Adam

Fred wrote:
Hi,

My newserver has a lot of old posts made here about shaver sockets and
I have tried to read them all.

It seems that shaver sockets with an isolating transformer can be
connected in the bathroom to the ring main via a FCU but as the ring
is often not available the more common approach is to connect it to
the light radial, where a FCU is not necessary but some people chose
to fit them for isolation purposes.

So far so good. However the supply earth to the shaver socket needs to
be bonded and this is where I begin to get confused. My questions a

What size cpc do you use? Some posts suggested big fat earth cable
(10mm^2, 16mm^2?), whereas others said the cpc of the T&E would be
fine. Which is right?

The bath, radiators, and basin taps are bonded with "big fat" earth
cable as far as I can see. I don't know where the cable runs under
the floorboards so I don't know whether it stays in the bathroom only,
or whether it goes back to the CU. This would have been done some time
ago, so possibly is not up to the current regs? Also some of the
copper pipe would have been replaced with plastic since then, so it
could probably do with someone having a look at it all.

Where do you connect the earth from the light radial to everything
else? Some posts suggested that if they both ran back to the CU's
earth bar, that would be fine, but other posts seemed to contradict
this and suggest it had to be done locally. Having a yellow and green
cable down the wall would not look pretty imho. I am pretty sure that
my light is not earth bonded at the moment so if I had a socket, this
would have to be done. Does it need doing even if I don't have a
socket fitted?

TIA

As you seem to be using the 16th edition not the 17th edition (nothing wrong
with that BTW) here is everything you need to know

http://web.archive.org/web/20051231060046/http://www.niceic.org.uk/downloads/NL139supp.pdf



--
Adam

On 16 Oct, 03:02, John Rumm wrote:

SNIP

The purpose of the EQ bonding is to limit the maximum *touch voltage one
can be exposed to. If the bond is too far away or made using too thin a
wire then this voltage could exceed the 50V allowed. Hence the
requirement that it is "close" to the room. That can mean in the rood
adjacent etc. If the CU were the other side of the wall or in the room
below, then you could make a fair case for that being close enough.

Hi John,

I presume by "could be in the rood adjacent" you meant the room
adjacent, rather than the road adjacent (which is what I first thought
of) you might like to correct the wiki if the error is there also.

Cheers

Chris
(not normally picky, but it pays to get electrickery right).

In message , John
Rumm writes
On 18/10/2010 16:45, wrote:
On 16 Oct, 03:02, John wrote:

SNIP

The purpose of the EQ bonding is to limit the maximum touch voltage one
can be exposed to. If the bond is too far away or made using too thin a
wire then this voltage could exceed the 50V allowed. Hence the
requirement that it is "close" to the room. That can mean in the rood
adjacent etc. If the CU were the other side of the wall or in the room
below, then you could make a fair case for that being close enough.

Hi John,

I presume by "could be in the rood adjacent" you meant the room

Indeed - my fingers are not fully under my control sometimes!

"... Your honour..."


--
geoff