Wiki: Pattress
meow...@care2.com
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]]
Martin Crossley
> For your perusal...
>
SNIP
>
> ===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.
>
Some 1960s metal back-boxes had nylon inserts for the (4BA) screws.
The screws are thus insulated. They are fine as long as any
replacement switches are plastic and re-use the original screws.
Dave Plowman (News)
It's also possible to buy fittings with plastic plugs which fit into the
screw holes thus insulating them. IIRC Some Wicks ones are like this.
--
*Growing old is inevitable, growing up is optional
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
Dave Liquorice
> 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).
--
Cheers
Dave.
Rod
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>
The Medway Handyman
> On Sat, 23 Aug 2008 17:59:54 -0700 (PDT), meow...@care2.com 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 search the TLC Direct site for 'pattress' you get a list of surface
mounted boxes in various finishes, but no plasterboard or metal boxes. Dry
lining/plasterboard & metal are referred to as simply 'boxes' and respond to
the search for 'back box' or 'box'.
Search SF for 'pattress' and all types of boxes result.
I think the wiki should use the terminology in most common use, rather than
the absolutely correct terminology.
--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
meow...@care2.com
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
Dave Plowman (News)
> 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 *
Andrew Gabriel
meow...@care2.com 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.
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]
Norman Billingham
"Dave Plowman (News)" <da...@davenoise.co.uk> wrote in message
news:4fd3d70...@davenoise.co.uk...
> In article <nyyfbegfubjuvyypb...@srv1.howhill.net>,
> Dave Liquorice <allsortsn...@howhill.com> 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.
Dave Plowman (News)
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*
John Rumm
> 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?criteria=pattress&source=15&SD=Y
--
Cheers,
John.
/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
John Rumm
>> 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.
Andy Wade
> 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.)
--
Andy
meow...@care2.com
> 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
Andy Champ
then, the guy who taught me was from Queensland - so it could be a
regional thing.
Andy
Dave Liquorice
>> "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.
True but I think pattress is not widely understood or particularly clear.
> Lots of diyers, tradespeople and sellers call them pattresses, so
> pattress is a valid name for them.
I've never heard the word used in that way. B-)
From the wiki point of view and using the title in other articles
"Electrical accessory mounting boxes" is a bit of a handful and is a
plural so if the article that wants to use it is talking singular you have
to step through a hoop...
> 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.
I think "Wiring Accessory Box" is the best as it says what it is in a
fairly generic way. Pattress really needs it's own page to describe the
old use as the mounting blocks for gas and electrical fittings, the use as
load spreading plates in building ties, etc, and a link to the Wiring
Accessory Box article. Redirects from "Back Box", "Flush Mounting Box",
"Surface Mounting Box" to, preferably the relevant section, of the Wiring
Accessory Box article would be useful.
--
Cheers
Dave.
Tanner-'op
> On Sun, 24 Aug 2008 10:57:43 -0700 (PDT), meow...@care2.com wrote:
>
>>> "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.
>
> True but I think pattress is not widely understood or particularly
> clear.
>
>> Lots of diyers, tradespeople and sellers call them pattresses, so
>> pattress is a valid name for them.
>
> I've never heard the word used in that way. B-)
Dave,
I was told to call surface mounted boxes for sockets/light switches etc
"patress boxes" by electricians from the time I started my apprenticeship as
a chippie way back in 1964 - and every electrician and electrical supplier
in my neck of the country has called them that - and are still doing so.
Tanner-'op
John Rumm
John Rumm
> 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 most commonly come across the term pattress used only for surface
mounting 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 expect there is a regional variation, but its certainly not the most
commonly used of the terms.
> 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.
Agreed - something generic for the article title would hence be best.
Grimly Curmudgeon
drugs began to take hold. I remember meow...@care2.com saying something
like:
>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.
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. Lazy diction has led to a generation simply
calling them patresses, missing the 'box' off - this may be worse in
some parts of the country than others.
Best to stick with the proper, traditional terms - damnit, we need
standards these days.
--
Dave
GS850x2 XS650 SE6a
"It's a moron working with power tools.
How much more suspenseful can you get?"
- House
Cicero
==================================
http://www.redgwick.co.uk/
Cic.
--
===================================
Using Ubuntu Linux
Windows shown the door
===================================
Andy Wade
> 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
Dave Plowman (News)
Tanner-'op <tannerop@i......nvalid.com> wrote:
> I was told to call surface mounted boxes for sockets/light switches etc
> "patress boxes" by electricians from the time I started my
> apprenticeship as a chippie way back in 1964 - and every electrician
> and electrical supplier in my neck of the country has called them that
> - and are still doing so.
Which would be fine for a regional FAQ. But unfortunately it's national
and in other areas it's not used.
--
*What do little birdies see when they get knocked unconscious? *
The Medway Handyman
> In article <6he6tpF...@mid.individual.net>,
> Tanner-'op <tannerop@i......nvalid.com> wrote:
>> I was told to call surface mounted boxes for sockets/light switches
>> etc "patress boxes" by electricians from the time I started my
>> apprenticeship as a chippie way back in 1964 - and every electrician
>> and electrical supplier in my neck of the country has called them
>> that - and are still doing so.
>
> Which would be fine for a regional FAQ. But unfortunately it's
> national and in other areas it's not used.
Perhaps we should use the terms in the Screwfix catalouge/web site? They
are national and seem to be becoming the modern day 'Bucks Book' if anyone
remembers that?
Yonks ago I was in the tool trade & customers would call asking for all
sorts of stuff. If there was any doubt they would refer to page so and so
in the Bucks Book. Everybody seemed to have one, even if they never bought
from Buck & Hickman.
We use the SF site like that here.
meow...@care2.com
wrote:
> In article <6he6tpFl11n...@mid.individual.net>,
> Tanner-'op <tannerop@i......nvalid.com> wrote:
>
> > I was told to call surface mounted boxes for sockets/light switches etc
> > "patress boxes" by electricians from the time I started my
> > apprenticeship as a chippie way back in 1964 - and every electrician
> > and electrical supplier in my neck of the country has called them that
> > - and are still doing so.
>
> Which would be fine for a regional FAQ. But unfortunately it's national
> and in other areas it's not used.
The other terms are no more or less regional than pattress.
NT
Dave Plowman (News)
<d46d7257-dcea-4fd2...@k37g2000hsf.googlegroups.com>,
<meow...@care2.com> wrote:
> > Which would be fine for a regional FAQ. But unfortunately it's national
> > and in other areas it's not used.
> The other terms are no more or less regional than pattress.
Perhaps you could tell me of a regional supplier's website where they talk
about pattresses as backing boxes?
And I'd be most surprised if any wholesaler in the land didn't understand
a 'flush metal 35mm two gang backing box'
--
*Aim Low, Reach Your Goals, Avoid Disappointment *
Dave Liquorice
> Perhaps we should use the terms in the Screwfix catalouge/web site?
Not a bad idea, they use "Mounting Box" as the generic title to cover
steel and drylining flush boxes under Home > Electrical > Switches &
Sockets > Mounting Boxes.
But surface boxes are lumped in amongst all the bits in Home > Electrical
> Conduit > Rigid Conduit.
--
Cheers
Dave.
Tanner-'op
> In article <6he6tpF...@mid.individual.net>,
> Tanner-'op <tannerop@i......nvalid.com> wrote:
>> I was told to call surface mounted boxes for sockets/light switches
>> etc "patress boxes" by electricians from the time I started my
>> apprenticeship as a chippie way back in 1964 - and every electrician
>> and electrical supplier in my neck of the country has called them
>> that - and are still doing so.
>
> Which would be fine for a regional FAQ. But unfortunately it's
> national and in other areas it's not used.
Dave,
Before retiring, I worked in several parts of the country over several
years - and on each job, a patress was... yes, a patress - which meant a
surface mounted switch/socket box (and that was understood by the local
tradesmen as well as us 'outsiders'. That seems pretty "national" to me.
As for the standard of the "Wiki" write-up on that subject (and many others)
I will pass no comment.
Tanner-'op
Owain
>> 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.
1930s works on electrical wiring have it as 'pateras' and use it to
describe the wooden circular or rectangular block on which the accessory
was fixed.
Owain
Owain
> There was an intermediate step between the wooden pattress and the
> modern surface mounting box.
At one time, wooden boxes were used for flush mounting accessories, as
well as for the construction of surface fuse boxes and the like.
Owain
meow...@care2.com
wrote:
> In article
> <d46d7257-dcea-4fd2-a5be-38d50b1cf...@k37g2000hsf.googlegroups.com>,
> <meow2...@care2.com> wrote:
>
> > > Which would be fine for a regional FAQ. But unfortunately it's national
> > > and in other areas it's not used.
> > The other terms are no more or less regional than pattress.
>
> Perhaps you could tell me of a regional supplier's website where they talk
> about pattresses as backing boxes?
>
> And I'd be most surprised if any wholesaler in the land didn't understand
> a 'flush metal 35mm two gang backing box'
'Pattress supplier' gives 3760 hits. 'Pattress' gives 29,800.
> And I'd be most surprised if any wholesaler in the land didn't understand
> a 'flush metal 35mm two gang backing box'
Indeed. I'd also be most surprised if any wholesaler in the land
didn't understand a 'flush metal 35mm two gang pattress'
I know it would be easy if all suppliers used one term, but they dont.
The Wiki can easily reflect that by using all the common terms.
NT
Dave Liquorice
> Before retiring, I worked in several parts of the country over several
> years - and on each job, a patress was... yes, a patress - which meant a
> surface mounted switch/socket box (and that was understood by the local
> tradesmen as well as us 'outsiders'. That seems pretty "national" to
> me.
Ah but the wiki entry refers to flush as well as surface mount boxen...
--
Cheers
Dave.
Grimly Curmudgeon
<spamb...@maxwell.myzen.co.uk> saying something like:
>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.
Hah. I've come across some of those in in ancient installations. Another
common one here are Bakelite cover / ceramic body incomer 2P switches on
a distribution board. Still plenty of them in use here and were still
being fitted in the late 60s - although I think in those cases it was
the spark using new old stock to use it up.
Dave Plowman (News)
Tanner-'op <tannerop@i......nvalid.com> wrote:
> > Which would be fine for a regional FAQ. But unfortunately it's
> > national and in other areas it's not used.
> Dave,
> Before retiring, I worked in several parts of the country over several
> years - and on each job, a patress was... yes, a patress - which meant a
> surface mounted switch/socket box (and that was understood by the local
> tradesmen as well as us 'outsiders'. That seems pretty "national" to me.
It's not recognised in any wholesaler I've used in London - and that's
plenty. Of course if you add plenty of description a decent counter person
may deduce what you mean - but many get annoyed by the use of it.
--
*Two many clicks spoil the browse *
meow...@care2.com
wrote:
> In article <6hg5duFlbrh...@mid.individual.net>,
> Tanner-'op <tannerop@i......nvalid.com> wrote:
>
> > > Which would be fine for a regional FAQ. But unfortunately it's
> > > national and in other areas it's not used.
> > Dave,
> > Before retiring, I worked in several parts of the country over several
> > years - and on each job, a patress was... yes, a patress - which meant a
> > surface mounted switch/socket box (and that was understood by the local
> > tradesmen as well as us 'outsiders'. That seems pretty "national" to me.
>
> It's not recognised in any wholesaler I've used in London - and that's
> plenty. Of course if you add plenty of description a decent counter person
> may deduce what you mean - but many get annoyed by the use of it.
Did you ask them for a pattress? If not, how would you know.
Its also not hard to find counter staff that dont know what youre
asking for because they've never been in the business themselves, and
know nothing beyond what the catalogue says.
None of this establishes anything germaine.
NT
Dave Plowman (News)
<b151a5e3-71e1-46f9...@l42g2000hsc.googlegroups.com>,
<meow...@care2.com> wrote:
> > It's not recognised in any wholesaler I've used in London - and that's
> > plenty. Of course if you add plenty of description a decent counter
> > person may deduce what you mean - but many get annoyed by the use of
> > it.
> Did you ask them for a pattress? If not, how would you know.
I did when I first arrived in London to be met with blank looks. The term
was/is in use in Aberdeen, my home town. I subsequently brought up the
subject with both pro electricians and a pal who has been in the
wholesaling game all his life and probably knows more about it than most.
Of course he had heard the term and referred to it as 'northern'.
> Its also not hard to find counter staff that dont know what youre
> asking for because they've never been in the business themselves, and
> know nothing beyond what the catalogue says.
So therefore in an FAQ it's best not to use jargon. Use a term which is
universally understood. You can continue to call it a humgrommet or
whatever in private with consenting adults.
> None of this establishes anything germaine.
There are plenty of examples where jargon varies regionally. And 'shows
you up' if you use the wrong term. Which is not what a newbie needs when
visiting a wholesaler for the first time.
--
*In "Casablanca", Humphrey Bogart never said "Play it again, Sam" *
Tony Bryer
> > Did you ask them for a pattress? If not, how would you know.
>
> I did when I first arrived in London to be met with blank looks.
It's certainly been used here for 40 years, though my first recollection
was to described the moulded round plate that you put under a batten
lampholder when not on a fireproof surface (per regs change mentioned
here previously)
--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
meow...@care2.com
wrote:
> In article
> <b151a5e3-71e1-46f9-ae36-c7cff15fb...@l42g2000hsc.googlegroups.com>,
> <meow2...@care2.com> wrote:
>
> > > It's not recognised in any wholesaler I've used in London - and that's
> > > plenty. Of course if you add plenty of description a decent counter
> > > person may deduce what you mean - but many get annoyed by the use of
> > > it.
> > Did you ask them for a pattress? If not, how would you know.
>
> I did when I first arrived in London to be met with blank looks. The term
> was/is in use in Aberdeen, my home town. I subsequently brought up the
> subject with both pro electricians and a pal who has been in the
> wholesaling game all his life and probably knows more about it than most.
> Of course he had heard the term and referred to it as 'northern'.
>
> > Its also not hard to find counter staff that dont know what youre
> > asking for because they've never been in the business themselves, and
> > know nothing beyond what the catalogue says.
>
> So therefore in an FAQ it's best not to use jargon. Use a term which is
> universally understood. You can continue to call it a humgrommet or
> whatever in private with consenting adults.
>
> > None of this establishes anything germaine.
>
> There are plenty of examples where jargon varies regionally. And 'shows
> you up' if you use the wrong term. Which is not what a newbie needs when
> visiting a wholesaler for the first time.
So far we've got 3 choices:
1. Pattress - widely used, but as you've pointed out, not universal
2. Backbox - again widely used but not universal, plus there's no
shortage of other things it can also mean
3. Electrical accessory wiring box - probably everyone would realise
what this is, but its simply too long for a wiki article title. It
also appears to cover other items such as junction boxes, and perhaps
even small CUs etc, its not an entirely clear name either.
Whichever term we use there will be various references to it in other
articles requiring links to this pattress article. Really there is no
winner here, there are issues with all 3 options. One plus of
'pattress' is that the history of the word and its DIY uses can be
included, both structural and historic electrical, so more information
would be there. Another plus, in common with backbox, is its short and
sweet.
The issues around the name(s) can be mentioned/discussed in the
article so no-one is left in confusion - that would be best whatever
title we use.
NT
Dave Plowman (News)
<d1a11a03-3d46-40fe...@v16g2000prc.googlegroups.com>,
<meow...@care2.com> wrote:
> 2. Backbox - again widely used but not universal, plus there's no
> shortage of other things it can also mean
What - in electrical terms?
--
*When did my wild oats turn to prunes and all bran?
meow...@care2.com
wrote:
> In article
> <d1a11a03-3d46-40fe-9855-a02dbd0e4...@v16g2000prc.googlegroups.com>,
> <meow2...@care2.com> wrote:
>
> > 2. Backbox - again widely used but not universal, plus there's no
> > shortage of other things it can also mean
>
> What - in electrical terms?
There's nothing that limits it to electrical afaics, so its wide open.
And within electrical it might refer to a junction box, a small CU,
and assorted items that arent part of house wiring.
NT
Dave Liquorice
> So far we've got 3 choices:
>
> 1. Pattress
> 2. Backbox
> 3. Electrical accessory wiring box
>
> The issues around the name(s) can be mentioned/discussed in the
> article so no-one is left in confusion - that would be best whatever
> title we use.
How does the disambiguation feature of a wiki work? I've not played with
that at all.
--
Cheers
Dave.
Dave Plowman (News)
<4c837a34-9ff1-4e07...@b30g2000prf.googlegroups.com>,
<meow...@care2.com> wrote:
> > > 2. Backbox - again widely used but not universal, plus there's no
> > > shortage of other things it can also mean
> >
> > What - in electrical terms?
> There's nothing that limits it to electrical afaics, so its wide open.
Then the whole idea is pointless.
> And within electrical it might refer to a junction box, a small CU,
> and assorted items that arent part of house wiring.
Are these more obscure terms?
Plenty of electrical bits and pieces consist of a plate of some sort which
fits a box. But with all the JBs and CUs I've seen the 'guts' are in the
box rather than on the plate.
> NT
--
*I never drink anything stronger than gin before breakfast *
meow...@care2.com
wrote:
> On Tue, 26 Aug 2008 04:37:55 -0700 (PDT), meow2...@care2.com wrote:
> > So far we've got 3 choices:
>
> > 1. Pattress
> > 2. Backbox
> > 3. Electrical accessory wiring box
>
> > The issues around the name(s) can be mentioned/discussed in the
> > article so no-one is left in confusion - that would be best whatever
> > title we use.
>
> How does the disambiguation feature of a wiki work? I've not played with
> that at all.
Disambig can be either its own separate page or a section in a page.
In this case the latter seems more suitable, since its unlikely we'd
have a page for the other pattresses any time this year
When I get time I'll do all the work and re-draft the article
NT
Mike Barnes
>Dave Liquorice wrote:
>> On Sat, 23 Aug 2008 17:59:54 -0700 (PDT), meow...@care2.com 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
>> 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 search the TLC Direct site for 'pattress' you get a list of surface
>mounted boxes in various finishes, but no plasterboard or metal boxes. Dry
>lining/plasterboard & metal are referred to as simply 'boxes' and respond to
>the search for 'back box' or 'box'.
That corresponds to my usage and the usage of people that I deal with
here in Cheshire. Surface fittings have pattresses. Flush fittings have
back boxes. It's a simple and useful distinction.
--
Mike Barnes
meow...@care2.com
> 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
John
<meow...@care2.com> wrote in message
news:05cda0e5-a6ef-4388...@k13g2000hse.googlegroups.com...
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?
Dave Plowman (News)
John <Who90...@ntlworld.com> 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.
--
*Sometimes I wake up grumpy; Other times I let him sleep.
meow...@care2.com
wrote:
> In article <O6oAk.3468$RJ3....@newsfe10.ams2>,
> John <Who90nos...@ntlworld.com> 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
John
<meow...@care2.com> wrote in message
news:25aa7fb4-8550-4388...@m3g2000hsc.googlegroups.com...
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?
meow...@care2.com
> <meow2...@care2.com> wrote in message
I've never used them - didnt even know they existed. I expect someone
else here has more experience of them
NT
Dave Plowman (News)
John <Who90...@ntlworld.com> wrote:
> NT
> http://www.tlc-direct.co.uk/Products/MKK2134.html
Yes - although you'll have to modify it somewhat. They have normal 2.5mm
fixing threads - so if you wish to put it between accessory and backing
box you'll need to drill them out. You may also need to remove the spare
'lugs' as these can interfere with some fittings.
It will look a bodge, though.
--
*I'm not as think as you drunk I am.
Appin
from "Dave Plowman (News)" <da...@davenoise.co.uk> contains these words:
> > Would you say that using one as a spacer for (say) a deeper accessory is
> > legitimate?
> Yes - although you'll have to modify it somewhat. They have normal 2.5mm
> fixing threads - so if you wish to put it between accessory and backing
> box you'll need to drill them out. You may also need to remove the spare
> 'lugs' as these can interfere with some fittings.
> It will look a bodge, though.
For a start, the machine screws are M3.5 -- that is the normal variety
for electrical boxes
You're not usually expected to drill them out but rather to use one set
for mounting the spacer and the other set for mounting the accessory.
Of course that sometimes causes problems of orentation and fitting of
some accessories.
Dave Plowman (News)
Appin <ap...@zetnet.co.uk> wrote:
> > > Would you say that using one as a spacer for (say) a deeper accessory is
> > > legitimate?
> > Yes - although you'll have to modify it somewhat. They have normal
> > 2.5mm fixing threads - so if you wish to put it between accessory and
> > backing box you'll need to drill them out. You may also need to remove
> > the spare 'lugs' as these can interfere with some fittings.
> > It will look a bodge, though.
> For a start, the machine screws are M3.5 -- that is the normal variety
> for electrical boxes
Indeed.
> You're not usually expected to drill them out but rather to use one set
> for mounting the spacer and the other set for mounting the accessory.
Most will tend to get used with plaster depth boxes which have only two
fixing lugs.
And you're not 'expected' to use them for this purpose - they're for
mounting a standard accessory to trunking etc. Use as a spacing frame is a
secondary one.
> Of course that sometimes causes problems of orentation and fitting of
> some accessories.
Some boxes also have only one adjustable lug - which most would fit so it
can be used for horizontal fixing. See also my point about the large
plastic lugs at the top fouling some dimmers, etc.
--
*People want trepanners like they want a hole in the head*
John Rumm
> And you're not 'expected' to use them for this purpose - they're for
> mounting a standard accessory to trunking etc. Use as a spacing frame is a
> secondary one.
ah, well if you use the things designed for the purpose of extending a
backbox rather than those designed for conduit, it all works much better
- the same screws just fit through the unthreaded lugs on the extender
and go into the original back box:
http://cpc.farnell.com/PL08925/electrical-lighting-security/product.us0?sku=bg-818
--
Cheers,
John.
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Dave Plowman (News)
John Rumm <see.my.s...@nowhere.null> wrote:
> > And you're not 'expected' to use them for this purpose - they're for
> > mounting a standard accessory to trunking etc. Use as a spacing frame
> > is a secondary one.
> ah, well if you use the things designed for the purpose of extending a
> backbox rather than those designed for conduit, it all works much better
> - the same screws just fit through the unthreaded lugs on the extender
> and go into the original back box:
http://cpc.farnell.com/PL08925/electrical-lighting-security/product.us0?sku=bg-818
Right - never seen those. Not that I'd be looking for them anyway. ;-)
--
*If all the world is a stage, where is the audience sitting?
Appin
from "Dave Plowman (News)" <da...@davenoise.co.uk> contains these words:
> Some boxes also have only one adjustable lug - which most would fit so it
> can be used for horizontal fixing.
And many boxes have -- or at least in the past had -- no adjustable lugs :-(
> See also my point about the large
> plastic lugs at the top fouling some dimmers, etc.
Been there, done that, got the t-shirt. Often :-(
Whilst they may still be current catalogue items, I think we're dealing
with something which is largely a relic of the past. I dare say I could
probably find one or two in a box of old bits somewhere around my
storeroom, but then I could also find a few packets of mounting flanges.
Remember them? Used to use them on 4 lug single-gang metal back boxes.
Fix flange to box using two of the lugs, then fix box to skirting by
woodscrews through the face of the flange. A whole lot simpler ( and
easier to align) than screwing through the side of the box into the
thickness of the skirting. But then flange boxes became readily
available and the problem was solved in a different and simpler way.