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Default Wiki: Pattress

For your perusal...


A '''pattress''' is the box that sits behind electrical sockets and
switches. Pattresses come in metal and plastic, and in surface mount
and flush versions.


==Pattress types==

===Metal flush mount pattress===
[[image:Pattress metal 406-3|thumb]]
Metal recessed pattresses are used to mount sockets & switches flush
to a solid wall. A recess is chiselled out for the pattress to sit in.
Knockouts are provided for [[cables|cable]] entry. These are the most
common domestic pattresses.


===Plastic surface mount pattress===
[[image:Pattress dbl 759-4.jpg|thumb]]
Plastic surface mount pattresses are used for electrical accessories
that sit on the surface of walls. The pattress is [[screw]]ed in
place, and knockouts are provided for [[cables|cable]] entry, either
via the sides or the rear.

These are available in different depths. The shallowest ones are
suitable for light switches where no screw block connections need to
be made behind the switch. Deeper ones are usually used for sockets,
but fitting sockets into shallow patresses is often possible, if
tight, and light switches with a few screw block connections behind
them will need the deep ones too.

Plastic surface mounting patresses are the 2nd most common domestic
type.


===Stud wall pattress===
[[image:Pattress PB 757-5.jpg|thumb]]
Plasterboard boxes are used to flush mount switches etc to [[Sheet
Materials|plasterboard]]. The picture shows the position of the grips
before and after fitting.


===Architrave pattress===
[[image: |thumb]]
Architrave pattresses are used with little architrave switches.


===Metal surface pattress===
[[image:Metal skt & pattress 754-7.jpg|thumb]]
Metal surface pattresses aren't very common in homes. They are used
with metal accessories, and are ideal for workshops (and other
environments) requiring particularly tough accessories.


===Twin single pattress===
[[image:Twin pattress 849-4.jpg|thumb]]
Twin pattresses are designed to take two single accessories. These are
used when 2 different accessories in one position are wanted. These
are not the same size as a double pattress.


===Non-standard pattress===
[[image:Pattress ashley 758-5.jpg|thumb]]
Non standard pattresses are sometimes seen. These generally don't fit
standard sockets. They're designed to achieve some advantage, such as
styling or compact size.

===3 & 4 gang pattress===
[[image: |thumb]]
3 way socket convertors use a pattress designed to [[screws|screw]]
onto the top of an existing single flush mount pattress. These turn a
1 way flush socket into a 3 way surface mount socket. Sometimes the
[[cables]] aren't long enough and need extending.

4 way socket convertors...


===Grid switches===
[[image:...]]
Grid switch pattresses are another type not often seen in homes. These
accept a number of accessories, which can be mixed at will in the one
pattress. Available accessories include various switches, dimmers, key
switches, indicators, etc. The accessories don't have any face plate,
a single full size faceplate is fitted last. MK is known for its grid
switch range.


==Junction boxes==
[[image: |thumb]]
[[Cables]] are often joined in pattresses, but their purpose is for
mounting switches and sockets. When a container is wanted only for
joining cables, a junction box is smaller & cheaper.


==Thermoplastic and Thermoset==
[[image: |thumb]]
Plastic pattresses intended for mains use are made from thermoset
plastics, mainly white bakelite. These don't soften when hot, and act
as a fire resistant container.

Similarly sized pattresses intended for phone networks are generally
made from thermoplastics. These come in more than one size, the larger
of which fits mains sockets. These can be bent slightly by hand, so
are easily recognised. They offer no heat or fire protection and don't
meet modern safety requirements for mains use.


==Style & fit==
[[image:Pattress corner detail Egatube & Tenby 850-4.jpg|thumb|Egatube
vs Tenby]]
Different brands of pattress have different corner detailing, intended
to match their own brand of accessories. Standard pattresses, switches
and sockets of different brands can be freely mixed, but the
difference in corner detailing can make a minority of combinations
look wrong. If mixing brands its best to check they look right
together before buying.

Non-standard pattresses can't be expected to fit standard sockets.

===Metal accessories===
[[image:Socket metal misfit 807-6.jpg|thumb|Oops!]]
Many metal accessories for surface mounting are a different size to
plastic pattresses, and will look an eyesore if fitted to each other.

This problem doesn't occur with the various retrofit metal accessories
on the market designed to fit standard plastic pattresses (and
recessed metal ones).


==Breakage==
[[Screws]] holding plastic pattresses in place should be done up until
they touch the pattress surface and no more. Any further tightening is
likely to break them.

Budget brand plastic pattresses can suffer a significant breakage rate
during installation, particularly if a fair amount of hole needs to be
made for [[cables|cable]] entry, or if the underlying wall is not
competely flat, or the installer doesn't appreciate their frailty.


===Earth connection===
Metal pattresses usually have an earth terminal for connecting to the
circuit earth.


===2 core wiring===
A small minority of houses still have 2 core [[lighting]] circuits.
Metal pattresses or accessories should not be fitted to such circuits
due to the absence of anything more than functional insulation as
protection against shock.

Sometimes people fit them and borrow an earth from a nearby socket
circuit. This works but its not considered best practice, as there's
always the possibility of the socket circuit being decommissioned
later, leaving the [[lighting]] accessories unearthed.

Plastic pattresses and accessories are the only type recommended for
these circuits. However that doesn't imply that fitting them is always
safe; some [[Historic Mains Cables|historic rubber wiring]] is so
badly perished that moving the wires during fitting is sometimes a
sizeable risk. If perishing is limited to just the wire ends, sleeving
may be fitted to replace the function of the damaged insulation.


==See Also==
* [[:Category:Electrical]]
* [[Special:Allpages|Wiki Contents]]
* [[Special:Categories|Wiki Subject Categories]]



[[Category:Electrical]]
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Default Wiki: Pattress

Dave Liquorice wrote:
On Sat, 23 Aug 2008 17:59:54 -0700 (PDT), wrote:

For your perusal...


A '''pattress''' is


Possibly not a word. At least my Concise OED doesn't have it (the online
OED is subscription) niether do a couple of other online dictionaries.
There is a wikipedia entry but that is wikipedia, pass the salt, thank
you.

However I have used the word, so it does "exist" but I use it to mean a
multiple outlet flex mounted trailing socket. What this article describes
I would call a "back box".

If you google pattress in the UK you get about 30,000 hits, some refering
to wall tie plates (the large metal plates used to spread the load on a
wall when ties are threaded through the building to stop it falling down).


Dreadful Wiki entry.

A pattress is, IMHO, the plate used *behind* a switch, socket, sconce
(or similar). Typically early pattresses were wood, often had a
'sculpted' edge (to match the cornices :-) ) and were usually varnished.

Obviously, more recent usage has covered more things, but it is still
not a back box. And surely "pattress box" should only apply to a surface
mount box which could indeed be sensibly mounted onto a pattress - and
never a standard galvanised in-wall type?

AIUI, the pattress did the following:

o Covered up an unsightly hole in the plaster - much more difficult in
the days before Polyfilla. And to hide any future cracking imnmediately
around a hole in said plaster. Especially important as early
installations would very often have been into existing buildings and
minimising any requirement for redecoration would have been important.

o Allowed any suitable fixing to be used between the pattress and the
wall (and possible gave enough area for two screws which might not have
been possible with some of the small switches used in early
installations) - but left the fixing between the switch and the pattress
to be standardised.

o Stopped the edges of a small switch from digging into soft-ish plaster.

o Stopped the switch from being screwed onto an uneven surface where
it would be easy to overstress it as the screws are tightened or in
later use.

o Reduced the visual impact of a switch just stuck on the wall - it
must have looked very odd before they were common.

o Gave somewhere for cable to turn (if it was being surface mounted).

Given they were used for gas as well, it might have had specific
purposes in that context.

Your use seems to make perfect sense if you consider that people have
often been seen making extension cables with ordinary sockets/socket
boxes mounted onto a bit of wood.

Wow! - you can *still* get wooden gas pattresses:

http://www.gofixit.co.uk/acatalog/wood_pattress_block.html

Yet again - common words largely ignored by dictionaries. So many
trade-related words simply have not made it into them - even if they
exist in the OED database.

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org


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Default Wiki: Pattress

On Aug 24, 10:43*am, Rod wrote:
Dave Liquorice wrote:
On Sat, 23 Aug 2008 17:59:54 -0700 (PDT), wrote:


For your perusal...


A '''pattress''' is


Possibly not a word. *At least my Concise OED doesn't have it (the online
OED is subscription) niether do a couple of other online dictionaries.
There is a wikipedia entry but that is wikipedia, pass the salt, thank
you.


However I have used the word, so it does "exist" but I use it to mean a
multiple outlet flex mounted trailing socket. What this article describes
I would call a "back box".


If you google pattress in the UK you get about 30,000 hits, some refering
to wall tie plates (the large metal plates used to spread the load on a
wall when ties are threaded through the building to stop it falling down).


Dreadful Wiki entry.

A pattress is, IMHO, the plate used *behind* a switch, socket, sconce
(or similar). Typically early pattresses were wood, often had a
'sculpted' edge (to match the cornices :-) ) and were usually varnished.

Obviously, more recent usage has covered more things, but it is still
not a back box. And surely "pattress box" should only apply to a surface
mount box which could indeed be sensibly mounted onto a pattress - and
never a standard galvanised in-wall type?

AIUI, the pattress did the following:

o * Covered up an unsightly hole in the plaster - much more difficult in
the days before Polyfilla. And to hide any future cracking imnmediately
around a hole in said plaster. Especially important as early
installations would very often have been into existing buildings and
minimising any requirement for redecoration would have been important.

o * Allowed any suitable fixing to be used between the pattress and the
wall (and possible gave enough area for two screws which might not have
been possible with some of the small switches used in early
installations) - but left the fixing between the switch and the pattress
to be standardised.

o * Stopped the edges of a small switch from digging into soft-ish plaster.

o * Stopped the switch from being screwed onto an uneven surface where
it would be easy to overstress it as the screws are tightened or in
later use.

o * Reduced the visual impact of a switch just stuck on the wall - it
must have looked very odd before they were common.

o * Gave somewhere for cable to turn (if it was being surface mounted).

Given they were used for gas as well, it might have had specific
purposes in that context.

Your use seems to make perfect sense if you consider that people have
often been seen making extension cables with ordinary sockets/socket
boxes mounted onto a bit of wood.

Wow! - you can *still* get wooden gas pattresses:

http://www.gofixit.co.uk/acatalog/wood_pattress_block.html

Yet again - common words largely ignored by dictionaries. So many
trade-related words simply have not made it into them - even if they
exist in the OED database.


You can still buy wooden electrical pattresses too.

Dictionaries are very useful tools, but are a bit overestimated imho.
Another example is 'anonymous' which dictionaries generally describe
as having no name, when usually it means declaring no name, which isnt
the same.

I'll do a bit more writing when I get the time, cheers everyone


NT
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Default Wiki: Pattress

Rod wrote:

A pattress is, IMHO, the plate used *behind* a switch, socket, sconce
(or similar). Typically early pattresses were wood, often had a
'sculpted' edge (to match the cornices :-) ) and were usually varnished.


or:

http://www.maplin.co.uk/Search.aspx?...source=15&SD=Y



--
Cheers,

John.

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Default Wiki: Pattress

In article et,
Dave Liquorice wrote:
A '''pattress''' is


Possibly not a word. At least my Concise OED doesn't have it (the
online OED is subscription) niether do a couple of other online
dictionaries. There is a wikipedia entry but that is wikipedia, pass
the salt, thank you.


However I have used the word, so it does "exist" but I use it to mean a
multiple outlet flex mounted trailing socket. What this article
describes I would call a "back box".


Yes - go into any wholesaler in London and you'd get a blank look if
asking for a pattress. And from my spell checker. ;-)

My opinion is it was those wood plates older surface mounted switches
were fixed to. So the nearest modern equivalent would be those rare
spacers which go between backing box and fitting - sometimes called
mounting frames.

I'd stick to backing box - that qualified by the material, size and type
will get you what's needed anywhere
Like metal flush 35mm 2 gang backing box

--
*A fool and his money are soon partying *

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


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Default Wiki: Pattress


"Dave Plowman (News)" wrote in message
...
In article et,
Dave Liquorice wrote:
A '''pattress''' is


Possibly not a word. At least my Concise OED doesn't have it (the
online OED is subscription) niether do a couple of other online
dictionaries. There is a wikipedia entry but that is wikipedia, pass
the salt, thank you.


However I have used the word, so it does "exist" but I use it to mean a
multiple outlet flex mounted trailing socket. What this article
describes I would call a "back box".


Yes - go into any wholesaler in London and you'd get a blank look if
asking for a pattress. And from my spell checker. ;-)

My opinion is it was those wood plates older surface mounted switches
were fixed to. So the nearest modern equivalent would be those rare
spacers which go between backing box and fitting - sometimes called
mounting frames.

I'd stick to backing box - that qualified by the material, size and type
will get you what's needed anywhere
Like metal flush 35mm 2 gang backing box



The full OED defines pattress as "A wooden or plastic block attached to a
surface to receive a gas bracket, electric light switch, ceiling rose, etc.;
the base of a wall socket."

Dates back to 1886 according to the OED, when it was a block for mounting a
gas fitting. They quote 1969 A. J. COKER Electr. Wiring (ed. 7) v. 81
"Pattress boxes are also available to convert flush-type to surface
mounting"

I've certainly always believed a pattress was surface mounting and I've
never used the term to mean a flush mounting box. But then dictionaries
reflect usage they don't create it.


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Default Wiki: Pattress

In article ,
Norman Billingham norman.at.tumulus.org.uk wrote:
I've certainly always believed a pattress was surface mounting and I've
never used the term to mean a flush mounting box. But then dictionaries
reflect usage they don't create it.


I think the problem is that the current pattress meaning is a regional
thing. So best avoided in an FAQ - unless fully explained. When dealing
with suppliers it's best to avoid jargon unless you're certain they'll
know what you mean.

--
*I wonder how much deeper the ocean would be without sponges*

Dave Plowman London SW
To e-mail, change noise into sound.
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Default Wiki: Pattress

Norman Billingham wrote:

The full OED defines pattress as "A wooden or plastic block attached to a
surface to receive a gas bracket, electric light switch, ceiling rose, etc.;
the base of a wall socket."

Dates back to 1886 according to the OED, when it was a block for mounting a
gas fitting. They quote 1969 A. J. COKER Electr. Wiring (ed. 7) v. 81
"Pattress boxes are also available to convert flush-type to surface
mounting"


The etymology it gives is interesting too:
"Probably an alteration of classical Latin pateras, plural of
PATERA n. (compare quot. 1905 at main sense)."

And the entry for PATERA is:
patera, n
Plural pateræ, pateras. Forms: 16- patera, 18 pattera.
[ classical Latin patera broad shallow bowl or dish,
perhaps the same Indo-European base as ancient Greek
{pi}{alpha}{tau}{gaacu}{nu}{eta} (see PATEN n.).

I've certainly always believed a pattress was surface mounting and I've
never used the term to mean a flush mounting box.


I agree entirely. I'd go further and say that the term should be
avoided altogether unless referring to the wooden blocks or moulded
mounting plates used in old wiring systems. For modern accessories
"flush mounting box" and "surface mounting box" are clear and unambiguous.

But then dictionaries reflect usage they don't create it.


Yes but... (... but we probably don't want the Queen of Hearts defining
technical vocabulary.)

--
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In article ,
writes:
For your perusal...


A '''pattress''' is the box that sits behind electrical sockets and


As others already said, that's the wrong word. I think "back box"
is the most commonly used term, for both surface and flush fitting.

switches. Pattresses come in metal and plastic, and in surface mount
and flush versions.


==Pattress types==

===Metal flush mount pattress===
[[image:Pattress metal 406-3|thumb]]
Metal recessed pattresses are used to mount sockets & switches flush
to a solid wall. A recess is chiselled out for the pattress to sit in.
Knockouts are provided for [[cables|cable]] entry. These are the most
common domestic pattresses.


===Plastic surface mount pattress===
[[image:Pattress dbl 759-4.jpg|thumb]]
Plastic surface mount pattresses are used for electrical accessories
that sit on the surface of walls. The pattress is [[screw]]ed in
place, and knockouts are provided for [[cables|cable]] entry, either
via the sides or the rear.


Surface mount types are available in square or rounded corners to
match different wiring accessory styles.

These are available in different depths. The shallowest ones are
suitable for light switches where no screw block connections need to
be made behind the switch. Deeper ones are usually used for sockets,
but fitting sockets into shallow patresses is often possible, if
tight, and light switches with a few screw block connections behind
them will need the deep ones too.


That paragraph applies to all types, and wants to be at a higher
heading level.

Plastic surface mounting patresses are the 2nd most common domestic
type.


===Stud wall pattress===
[[image:Pattress PB 757-5.jpg|thumb]]
Plasterboard boxes are used to flush mount switches etc to [[Sheet
Materials|plasterboard]]. The picture shows the position of the grips
before and after fitting.


===Architrave pattress===
[[image: |thumb]]
Architrave pattresses are used with little architrave switches.


and Klik lighting sockets.

===Metal surface pattress===
[[image:Metal skt & pattress 754-7.jpg|thumb]]
Metal surface pattresses aren't very common in homes. They are used
with metal accessories, and are ideal for workshops (and other
environments) requiring particularly tough accessories.


For proper fitting of the wiring accessory, the back box and
accessory should be matched from the same range.

===Twin single pattress===
[[image:Twin pattress 849-4.jpg|thumb]]
Twin pattresses are designed to take two single accessories. These are
used when 2 different accessories in one position are wanted. These
are not the same size as a double pattress.


They can only be used with standard 86mm square accessories.
Other accessory styles won't fit.

===Non-standard pattress===
[[image:Pattress ashley 758-5.jpg|thumb]]
Non standard pattresses are sometimes seen. These generally don't fit
standard sockets. They're designed to achieve some advantage, such as
styling or compact size.

===3 & 4 gang pattress===
[[image: |thumb]]
3 way socket convertors use a pattress designed to [[screws|screw]]
onto the top of an existing single flush mount pattress. These turn a
1 way flush socket into a 3 way surface mount socket. Sometimes the
[[cables]] aren't long enough and need extending.

4 way socket convertors...


===Grid switches===
[[image:...]]
Grid switch pattresses are another type not often seen in homes. These
accept a number of accessories, which can be mixed at will in the one
pattress. Available accessories include various switches, dimmers, key
switches, indicators, etc. The accessories don't have any face plate,
a single full size faceplate is fitted last. MK is known for its grid
switch range.


==Junction boxes==
[[image: |thumb]]
[[Cables]] are often joined in pattresses, but their purpose is for
mounting switches and sockets. When a container is wanted only for
joining cables, a junction box is smaller & cheaper.


==Thermoplastic and Thermoset==


Better to use the full terms Thermosoftening and Thermosetting.

[Just about to reboot computer to upgraded OS, so I'm sending
as far as I got -- might read the rest later]

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
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Default Wiki: Pattress

Andrew Gabriel wrote:

A '''pattress''' is the box that sits behind electrical sockets and


As others already said, that's the wrong word. I think "back box"
is the most commonly used term, for both surface and flush fitting.


"Electrical accessory mounting boxes" might be simplest, with back box,
pattress, dry lining box etc defined within and perhaps as redirects to
the article.



--
Cheers,

John.

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On Aug 24, 3:51*pm, John Rumm wrote:
Andrew Gabriel wrote:
A '''pattress''' is the box that sits behind electrical sockets and


As others already said, that's the wrong word. I think "back box"
is the most commonly used term, for both surface and flush fitting.


"Electrical accessory mounting boxes" might be simplest, with back box,
pattress, dry lining box etc defined within and perhaps as redirects to
the article.



Yes, lets just be practical about it. Lots of diyers, tradespeople and
sellers call them pattresses, so pattress is a valid name for them.
Ditto backboxes, ditto wiring accessory boxes.

I could very easily be mistaken on this, but I thought the use of
'pattress' for moden backboxes was the result of the continuing to use
the word for the bit that goes behind a socket, even though today the
box shape of it is different to the old flat plates. Hence 'pattess'
describes 3 different things today - backboxes, the older little
wooden plates, and big structural loadpsreading plates - but for the
most part, electrical accessory backboxes.

I dont think any one particular term as an article heading is going to
be a winner, as none are in universal use, and all are terms in
widepsread use.

PS if anyone can supply a pic of an architrave pattress and 3 & 4 way
boxes, please do.


NT
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Default Wiki: Pattress

Just to add my 2p worth, I've always called them "Pattress Boxes". But
then, the guy who taught me was from Queensland - so it could be a
regional thing.

Andy
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wrote:
On Aug 24, 3:51 pm, John Rumm wrote:
Andrew Gabriel wrote:
A '''pattress''' is the box that sits behind electrical sockets and
As others already said, that's the wrong word. I think "back box"
is the most commonly used term, for both surface and flush fitting.

"Electrical accessory mounting boxes" might be simplest, with back box,
pattress, dry lining box etc defined within and perhaps as redirects to
the article.



Yes, lets just be practical about it. Lots of diyers, tradespeople and
sellers call them pattresses, so pattress is a valid name for them.
Ditto backboxes, ditto wiring accessory boxes.

I could very easily be mistaken on this, but I thought the use of
'pattress' for moden backboxes was the result of the continuing to use
the word for the bit that goes behind a socket, even though today the
box shape of it is different to the old flat plates. Hence 'pattess'
describes 3 different things today - backboxes, the older little
wooden plates, and big structural loadpsreading plates - but for the
most part, electrical accessory backboxes.

I dont think any one particular term as an article heading is going to
be a winner, as none are in universal use, and all are terms in
widepsread use.

PS if anyone can supply a pic of an architrave pattress and 3 & 4 way
boxes, please do.


NT



--
Cheers,

John.

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Grimly Curmudgeon wrote:

I see what you're getting at, but the pattress has always been just the
wooden plate and the term 'pattress box' refers only to the surface box
that would screw onto it.


There was an intermediate step between the wooden pattress and the
modern surface mounting box.

Originally wiring accessories for surface mounting had terminals open at
the back and were screwed to the wooden pattress. When the wiring regs
introduced the requirement for all connections to be enclosed in
fireproof material (12th or 13th edition?) many manufacturers introduced
moulded mounting plates (aka back plates or pattresses) that could be
used either on a wooden pattress or directly on a wall. Thus the wooden
pattress started to disappear. The next step was the introduction of
the surface mounting box as we now know it, enabling 'flush-mount'
wiring accessories to be surface mounted.

I guess this is how common use of the term pattress passed from the
wooden item to the surface mounting (pattress) box. There's no such
continuity with flush mount wiring accessories and their metal back
boxes, which were in use before the wooden pattress disappeared. That's
why using pattress to refer to flush mounting boxes only confuses the
issue and is quite wrong, IMHO.

--
Andy
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On Sat, 23 Aug 2008 17:59:54 -0700, meow2222 wrote:

For your perusal...


A '''pattress''' is the box that sits behind electrical sockets and
switches. Pattresses come in metal and plastic, and in surface mount and
flush versions.


==Pattress types==

===Metal flush mount pattress===
[[image:Pattress metal 406-3|thumb]]
Metal recessed pattresses are used to mount sockets & switches flush to
a solid wall. A recess is chiselled out for the pattress to sit in.
Knockouts are provided for [[cables|cable]] entry. These are the most
common domestic pattresses.


===Plastic surface mount pattress===
[[image:Pattress dbl 759-4.jpg|thumb]] Plastic surface mount pattresses
are used for electrical accessories that sit on the surface of walls.
The pattress is [[screw]]ed in place, and knockouts are provided for
[[cables|cable]] entry, either via the sides or the rear.

These are available in different depths. The shallowest ones are
suitable for light switches where no screw block connections need to be
made behind the switch. Deeper ones are usually used for sockets, but
fitting sockets into shallow patresses is often possible, if tight, and
light switches with a few screw block connections behind them will need
the deep ones too.

Plastic surface mounting patresses are the 2nd most common domestic
type.


===Stud wall pattress===
[[image:Pattress PB 757-5.jpg|thumb]] Plasterboard boxes are used to
flush mount switches etc to [[Sheet Materials|plasterboard]]. The
picture shows the position of the grips before and after fitting.


===Architrave pattress===
[[image: |thumb]]
Architrave pattresses are used with little architrave switches.


===Metal surface pattress===
[[image:Metal skt & pattress 754-7.jpg|thumb]] Metal surface pattresses
aren't very common in homes. They are used with metal accessories, and
are ideal for workshops (and other environments) requiring particularly
tough accessories.


===Twin single pattress===
[[image:Twin pattress 849-4.jpg|thumb]] Twin pattresses are designed to
take two single accessories. These are used when 2 different accessories
in one position are wanted. These are not the same size as a double
pattress.


===Non-standard pattress===
[[image:Pattress ashley 758-5.jpg|thumb]] Non standard pattresses are
sometimes seen. These generally don't fit standard sockets. They're
designed to achieve some advantage, such as styling or compact size.

===3 & 4 gang pattress===
[[image: |thumb]]
3 way socket convertors use a pattress designed to [[screws|screw]] onto
the top of an existing single flush mount pattress. These turn a 1 way
flush socket into a 3 way surface mount socket. Sometimes the [[cables]]
aren't long enough and need extending.

4 way socket convertors...


===Grid switches===
[[image:...]]
Grid switch pattresses are another type not often seen in homes. These
accept a number of accessories, which can be mixed at will in the one
pattress. Available accessories include various switches, dimmers, key
switches, indicators, etc. The accessories don't have any face plate, a
single full size faceplate is fitted last. MK is known for its grid
switch range.


==Junction boxes==
[[image: |thumb]]
[[Cables]] are often joined in pattresses, but their purpose is for
mounting switches and sockets. When a container is wanted only for
joining cables, a junction box is smaller & cheaper.


==Thermoplastic and Thermoset==
[[image: |thumb]]
Plastic pattresses intended for mains use are made from thermoset
plastics, mainly white bakelite. These don't soften when hot, and act as
a fire resistant container.

Similarly sized pattresses intended for phone networks are generally
made from thermoplastics. These come in more than one size, the larger
of which fits mains sockets. These can be bent slightly by hand, so are
easily recognised. They offer no heat or fire protection and don't meet
modern safety requirements for mains use.


==Style & fit==
[[image:Pattress corner detail Egatube & Tenby 850-4.jpg|thumb|Egatube
vs Tenby]]
Different brands of pattress have different corner detailing, intended
to match their own brand of accessories. Standard pattresses, switches
and sockets of different brands can be freely mixed, but the difference
in corner detailing can make a minority of combinations look wrong. If
mixing brands its best to check they look right together before buying.

Non-standard pattresses can't be expected to fit standard sockets.

===Metal accessories===
[[image:Socket metal misfit 807-6.jpg|thumb|Oops!]] Many metal
accessories for surface mounting are a different size to plastic
pattresses, and will look an eyesore if fitted to each other.

This problem doesn't occur with the various retrofit metal accessories
on the market designed to fit standard plastic pattresses (and recessed
metal ones).


==Breakage==
[[Screws]] holding plastic pattresses in place should be done up until
they touch the pattress surface and no more. Any further tightening is
likely to break them.

Budget brand plastic pattresses can suffer a significant breakage rate
during installation, particularly if a fair amount of hole needs to be
made for [[cables|cable]] entry, or if the underlying wall is not
competely flat, or the installer doesn't appreciate their frailty.


===Earth connection===
Metal pattresses usually have an earth terminal for connecting to the
circuit earth.


===2 core wiring===
A small minority of houses still have 2 core [[lighting]] circuits.
Metal pattresses or accessories should not be fitted to such circuits
due to the absence of anything more than functional insulation as
protection against shock.

Sometimes people fit them and borrow an earth from a nearby socket
circuit. This works but its not considered best practice, as there's
always the possibility of the socket circuit being decommissioned later,
leaving the [[lighting]] accessories unearthed.

Plastic pattresses and accessories are the only type recommended for
these circuits. However that doesn't imply that fitting them is always
safe; some [[Historic Mains Cables|historic rubber wiring]] is so badly
perished that moving the wires during fitting is sometimes a sizeable
risk. If perishing is limited to just the wire ends, sleeving may be
fitted to replace the function of the damaged insulation.


==See Also==
* [[:Category:Electrical]]
* [[Special:Allpages|Wiki Contents]]
* [[Special:Categories|Wiki Subject Categories]]



[[Category:Electrical]]


==================================
http://www.redgwick.co.uk/

Cic.
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Using Ubuntu Linux
Windows shown the door
===================================
  #25   Report Post  
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Posts: 9,560
Default Wiki: Pattress

On Aug 24, 1:59*am, wrote:
For your perusal...


Hopefully the final draft now, with lots of input added...


'''Pattress''' usually means the box that sits behind electrical
sockets and switches, though it has other meanings too. Modern
electrical pattress boxes come in metal and plastic, and in surface
mount and flush versions.


==Uses of the word 'pattress'==
'Pattress' has more than one meaning in DIY. Its also a word whose
meaning has changed relatively quickly over time, resulting in
significant disagreement over which meanings are correct.

===History===
[[image:Socket_(__)_785-4.jpg|thumb|old wood pattress plate]]

Pattress is derived from the latin 'pateras' meaning a shallow bowl or
plate.

In the 1800s 'pattress' was used to mean the flat wooden plates that
gas lighting equipment was mounted on.

In the 1930s electrical accessories were mounted on wooden plates, and
these were mainly referred to as 'pateras.' The anglicised version
'pattress' gradually took over from pateras.

When wiring regs required electrical accessories to be housed in
fireproof containers, a box was used between the wooden pateras and
socket, instead of mounting it directly to the pateras. This was known
as a pattress box. Over time this became known as a pattress.

Today many trade and DIY people refer to any electrical backbox as a
pattress. There are also many that consider only surface mount boxes
to be pattresses, and many that don't call any type of backbox a
pattress. Unfortunately this is equally true of the other names for
these things, so we just have to be aware of the differing usage of
the term.

The electrical boxes used behind sockets and switches are variously
known as pattresses, wiring accessory boxes, boxes, and backboxes,
with none of these terms being universal.


===Non-electrical pattresses===
The word 'pattress' also describes flattish iron plates used for load
spreading, as used to tie houses with structural defects together.



==Pattress types==

===Metal flush mount pattress===
[[image:Pattress metal 406-3|thumb]]
Metal recessed pattresses are used to mount sockets & switches flush
to a solid wall. A recess is chiselled out for the pattress to sit in.
Knockouts are provided for [[cables|cable]] entry. These are the most
common domestic pattresses.


===Plastic surface mount pattress===
[[image:Pattress dbl 759-4.jpg|thumb]]
Plastic surface mount pattresses are used for electrical accessories
that sit on the surface of walls. The pattress is [[screws|screwed]]
in place, and knockouts are provided for [[cables|cable]] entry,
either via the sides or the rear.

These are available in different depths. The shallowest ones are
suitable for light switches where no screw block connections need to
be made behind the switch. Deeper ones are usually used for sockets,
but fitting sockets into shallow patresses is often possible, if
tight, and light switches with a few screw block connections behind
them will need the deep ones too.

Plastic surface mounting patresses are the second most common domestic
type.


===Stud wall pattress===
[[image:Pattress PB 757-5.jpg|thumb]]
Plasterboard boxes are used to flush mount switches etc to [[Sheet
Materials|plasterboard]]. The picture shows the position of the grips
before and after fitting.


===Architrave pattress===
Architrave pattresses are used with little architrave switches.


===Metal surface pattress===
[[image:Metal skt & pattress 754-7.jpg|thumb]]
Metal surface pattresses aren't very common in homes. They are used
with metal accessories, and are ideal for workshops (and other
environments) requiring particularly tough accessories.


===Twin single pattress===
[[image:Twin pattress 849-4.jpg|thumb]]
Twin pattresses are designed to take two single accessories. These are
used when 2 different accessories in one position are wanted. These
are not the same size as a double pattress.


===Non-standard pattress===
[[image:Pattress ashley 758-5.jpg|thumb]]
Non standard pattresses are sometimes seen. These generally don't fit
standard sockets. They're designed to achieve some advantage, such as
styling or compact size.

===3 & 4 gang pattress===
3 way socket convertors use a pattress designed to [[screws|screw]]
onto the top of an existing single flush mount pattress. These turn a
1 way flush socket into a 3 way surface mount socket. Sometimes the
[[cables]] aren't long enough and need extending.

4 way socket convertors...


===Grid switches===
(pic wanted)
Grid switch pattresses are another type not often seen in homes. These
accept a number of accessories, which can be mixed at will in the one
box. Available accessories include various switches, dimmers, key
switches, indicators, etc. The accessories don't have any face plate,
a single full size faceplate is fitted last. MK is known for its grid
switch range.


===Round conduit boxes===
Round boxes forming part of a conduit system are sometimes seen in
houses, though not often.


==Junction boxes==
[[image: |thumb]]
[[Cables]] are often joined in pattresses, but their purpose is for
mounting switches and sockets. When a container is wanted only for
joining cables, a junction box is smaller & cheaper.

==Depth==
Plastic surface pattresses are widely available in different depths,
ranging from 16mm (mainly for switches) to 47mm (mainly for sockets).

Other types of pattress are also found in different depths, but less
often.


==Thermoplastic and Thermoset==
[[image: |thumb]]
Plastic pattresses intended for mains use are made from thermoset
plastics, mainly white bakelite. These don't soften when hot, and act
as a fire resistant container.

Similarly sized pattresses intended for phone networks are generally
made from thermoplastics. These come in more than one size, the larger
of which fits mains sockets. These can be bent slightly by hand, so
are easily recognised. They offer no heat or fire protection and don't
meet modern safety requirements for mains use.


==Style & fit==
[[image:Pattress corner detail Egatube & Tenby 850-4.jpg|thumb|Egatube
vs Tenby]]
Different brands of pattress have different corner detailing, intended
to match their own brand of accessories. Standard pattresses, switches
and sockets of different brands can be freely mixed, but the
difference in corner detailing can make a minority of combinations
look wrong. If mixing brands its best to check they look right
together before buying.

Non-standard pattresses can't be expected to fit standard sockets.

===Metal accessories===
[[image:Socket metal misfit 807-6.jpg|thumb|Oops!]]
Many metal accessories for surface mounting are a different size to
plastic pattresses. The screw spacing is the same, but the outer size
isn't. These are an eyesore if one type is fitted to the other.

This problem doesn't occur with the various retrofit metal accessories
on the market designed to fit standard plastic pattresses (and
recessed metal ones). It only applies to the traditional functional
metal sockets & backboxes.


==Breakage==
[[Screws]] holding plastic pattresses in place should be done up until
the screwhead touches the pattress surface, and no more. Any further
tightening is likely to break the brittle plastic.

Budget brand plastic pattresses can suffer a significant breakage rate
during installation, particularly if a fair amount of hole needs to be
made for [[cables|cable]] entry, or if the underlying wall is not
competely flat, or the installer doesn't appreciate their frailty.


==Earth connection==
Metal pattresses have an earth terminal for connecting to the circuit
earth. A sleeved wire should be run from the socket earth terminal to
the backbox.


===2 core wiring===
A small minority of houses still have old 2 core [[lighting]]
circuits. Metal pattresses or accessories should not be fitted to such
circuits due to the absence of anything more than functional
insulation as protection against shock.

Sometimes people fit them and borrow an earth from a nearby socket
circuit. This works but its not considered best practice, as there's
always the possibility of the socket circuit being decommissioned
later, leaving the [[lighting]] accessories unearthed. Hence its not
wiring regulations compliant.

Plastic pattresses and accessories are the only type recommended for
these circuits. However that doesn't imply that fitting them is always
safe; some [[Historic Mains Cables|historic rubber wiring]] is so
badly perished that moving the wires during fitting is sometimes a
sizeable risk. If perishing is limited to just the wire ends, sleeving
may be fitted to replace the function of the damaged insulation.


==Extension leads==
Surface pattress boxes are not designed for use on extension leads.
They have no cordgrip, and are brittle, which is not ideal for
portable use. Despite this they see fairly widespread use in extension
leads, so we will describe how to make these not-recommended leads as
safe as possible.

The main problem is the lack of cordgrip. There are 4 ways to
implement a cordgrip.
# Knockout 3 of the knockouts in a row on one side/top/bottom of the
pattress, and thread the lead through all 3 in a zigzag pattern. This
makes a fully effective cordgrip.
# The pattess box can be mounted on a piece of wood and a cordgrip
from a mains plug used to secure the lead inside the box. The 2 screws
go into the backing wood.
# Knotting the wire is sometimes used, but this is only partially
effective.
# A few surface pattress boxes do have cordgrips (eg Marbo).

Breakability can be reduced to some extent by mounting the pattress
box on a piece of chipboard that's larger all round than the box.
Chipboard and MDF are best as they're soft enough to reduce peak
impact forces.


==See Also==
* [[:Category:Electrical]]
* [[Special:Allpages|Wiki Contents]]
* [[Special:Categories|Wiki Subject Categories]]



[[Category:Electrical]]


NT


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wrote in message
...
On Aug 24, 1:59 am, wrote:
For your perusal...



what are those white plastic spacers that can (Could) be bought to
effectively increase the depth of a box by bringing the wiring accessory
forward about 6mm?


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In article ,
John wrote:
what are those white plastic spacers that can (Could) be bought to
effectively increase the depth of a box by bringing the wiring accessory
forward about 6mm?


IIRC, called mounting frames.

--
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Default Wiki: Pattress

On Sep 18, 11:04*am, "Dave Plowman (News)"
wrote:
In article ,
* *John wrote:

what are those white plastic spacers that can (Could) be bought to
effectively increase the depth of a box by bringing the wiring accessory
forward about 6mm?


IIRC, called mounting frames.


Added, thanks. Just got the images to sort out now.


NT
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Default Wiki: Pattress


wrote in message
...
On Sep 18, 11:04 am, "Dave Plowman (News)"
wrote:
In article ,
John wrote:

what are those white plastic spacers that can (Could) be bought to
effectively increase the depth of a box by bringing the wiring accessory
forward about 6mm?


IIRC, called mounting frames.


Added, thanks. Just got the images to sort out now.


NT

Thanks - I was trying to refer to one recently but didn't know the name and
couldn't find them.

http://www.tlc-direct.co.uk/Products/MKK2134.html

Would you say that using one as a spacer for (say) a deeper accessory is
legitimate?


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