I think I know the answer here, and it is fairly easily remedied - but
it made me wonder.

In replacing some double sockets, it appears two of them have no metal
back box. There is room for a box and in fact it appears they were
originally present but have been removed. I think this was to make it
easier to fit slightly bulky new sockets to these two positions. The
sockets are attached by wood screws which go into wooden studs behind
the opening. They are otherwise neatly fitted, with tidy wiring and
sleeved earth etc.

It won't be difficult to replace these - which is of course what we
will do. What I am wondering is - with plastic MK double sockets - what
is the effect of not having an (earthed) back box? Presumably the
fixing screws are at theoretical risk of becoming live? Any other
possible dangers?

On 26 Feb 2006 00:28:33 -0800 someone who may be "mjb"
wrote this:-

The
sockets are attached by wood screws which go into wooden studs behind
the opening.

What is the wall made of?

What I am wondering is - with plastic MK double sockets - what
is the effect of not having an (earthed) back box?

The box is there partly to provide a non-flammable enclosure for the
live parts.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"David Hansen" wrote in message
...
On 26 Feb 2006 00:28:33 -0800 someone who may be "mjb"
wrote this:-

The
sockets are attached by wood screws which go into wooden studs behind
the opening.

What is the wall made of?

What I am wondering is - with plastic MK double sockets - what
is the effect of not having an (earthed) back box?

The box is there partly to provide a non-flammable enclosure for the
live parts.



??? how does that make sense when uing a plastic box?

On Sun, 26 Feb 2006 12:40:11 GMT someone who may be "Stephen Dawson"
wrote this:-

The box is there partly to provide a non-flammable enclosure for the
live parts.

??? how does that make sense when uing a plastic box?

The cover of a typical consumer unit is made out of plastic too. Not
all plastics are the same and the ones selected for electrical
equipment are selected specifically for characteristics that include
zero or low flammability.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Sun, 26 Feb 2006 13:46:53 +0000, David Hansen
wrote:

On Sun, 26 Feb 2006 12:40:11 GMT someone who may be "Stephen Dawson"
wrote this:-

The box is there partly to provide a non-flammable enclosure for the
live parts.

??? how does that make sense when uing a plastic box?

The cover of a typical consumer unit is made out of plastic too. Not
all plastics are the same and the ones selected for electrical
equipment are selected specifically for characteristics that include
zero or low flammability.

It's a very old requirement going back to the days of rubber insulated
cables and scruit connectors when I *think* the requirement was for an
earthed metal or hardwood (oak) box. Presumably oak had sufficiently
low flammability.

DG

mjb wrote:
It won't be difficult to replace these - which is of course what we
will do. What I am wondering is - with plastic MK double sockets - what
is the effect of not having an (earthed) back box? Presumably the
fixing screws are at theoretical risk of becoming live? Any other
possible dangers?

But that would be no different if you were to use a plastic back box, of
the type commonly used in stud partitions...

David

Derek ^ wrote:

Presumably oak had sufficiently low flammability.

I think because oak chars rather than burns it is practically
self-extinguishing, how well that applies to thinner pieces I don't know.