Is it a good idea to tin mains flex conductors....
Sven Franklyn Weil
....before connecting them to a plug or trailing socket?
Just finished making some short extension "pigtails" for some equipment
and I did that so the contact screw wouldn't shove all the wires to the
sides of the hole in the terminal. I was using .75 millemeter wire.
==
Sven
ch...@areti.co.uk
It does (as you say) make sure that there aren't any loose 'whiskersa
floating around when you connect flex under a screw.
On the other hand tinning the end concentrates any flexing of the
wire in the section adjacent to the tinning and any movement in the
joint will cause the wire to fail there.
On balance I think I'm against tinning unless there's absolutely no
other way to ensure that all the strands of the wire are properly
gripped. If there is a serious problem it suggests that the wire
isn't the right size for the terminals (or the other way around).
--
Chris Green (cgr...@x-1.net)
Andrew Gabriel
No, you should never tin flex in this way. Solder is soft
and flows under pressure, so the terminal will become loose.
If you ever buy something with tinned flex*, cut the tinned
part off. It was done to enable rapid testing on the
production line, and not for your ease of wiring. This isn't
much of an issue now that all items for domestic use come
fitted with a plug, but it used to be.
The correct way to do this is to crimp on bootlace furrules.
You could solder on bootlace furrules - that would be OK
too providing you don't get any thick layer of solder on
the outside of the furrule.
*I'm not referring to stranded copper where the individual
strands are tinned - this is just a very thin layer to
protect against oxidation.
--
Andrew Gabriel
Consultant Software Engineer
Dave Liquorice
> ....before connecting them to a plug or trailing socket?
No, over time the solder "creeps" under the pressure from the screw
and the contact will become lose creating a heating problem or in
worst case a fire.
> Just finished making some short extension "pigtails" for some
> equipment and I did that so the contact screw wouldn't shove all the
> wires to the sides of the hole in the terminal. I was using .75
> millemeter wire.
With the smaller diameter flexes I tend to twist the bundle of stands
together and then fold back on itself before inserting into the
terminal. This creates enough bulk for the screw to bite on.
--
Cheers new...@howhill.com
Dave. Remove "spam" for valid email.
adr...@flexplugsrockroll.freeserve.co.uk
The reason is that solder contains lead. Lead suffers from metal creep at
temperatures above 20 degrees. The end result of this is that joints made by
compression (eg. screws) will work loose due to the solder creeping over
time. This does not happen with copper since its creep temperature is over
100 degrees.
Adrian
Sven Franklyn Weil wrote in message ...
Owain
news:aabd7d$spf$1...@new-usenet.uk.sun.com...
| In article <slrnachkb...@gordsven.com>,
| sv...@gordsven.com (Sven Franklyn Weil) writes:
| > ....before connecting them to a plug or trailing socket?
| and flows under pressure, so the terminal will become loose.
I agree, but there are differing opinions, perhaps depending on the
circumstances. In the IEE Monograph "Electrical Safety at Work", Chapter 7
Safety in Schools, I G B Hall, Associate IEIE, writes:
Furthermore it is strongly urged that all cable ends are doubled as
necessary and tinned to ensure good and safe contact by terminal screwe.
This latter practice should ensure that not only during initial assembly but
also during future tightening of screws (as in periodical inspection) there
will be no sheared strands of wire.
Owain
Steven Briggs
<use...@gowan-hill.com> writes
>
>I agree, but there are differing opinions, perhaps depending on the
>circumstances. In the IEE Monograph "Electrical Safety at Work", Chapter 7
>Safety in Schools, I G B Hall, Associate IEIE, writes:
>
> Furthermore it is strongly urged that all cable ends are doubled as
>necessary and tinned to ensure good and safe contact by terminal screwe.
>This latter practice should ensure that not only during initial assembly but
>also during future tightening of screws (as in periodical inspection) there
>will be no sheared strands of wire.
>
>Owain
>
>
>
That seems very bad advice from Mr Hall. You aren't going to get a "good
and safe contact" onto a tinned wire in the long term.
Is that a current book or some dusty tome from the distant past?
--
Steven Briggs
Knaresborough
North Yorkshire
(Replace bin with steven if emailing!)
cetltd
<b...@sbriggs.demon.co.uk> writes
>In article <aae94t$nq4$1...@knossos.btinternet.com>, Owain
><use...@gowan-hill.com> writes
>
>>
>>I agree, but there are differing opinions, perhaps depending on the
>>circumstances. In the IEE Monograph "Electrical Safety at Work", Chapter 7
>>Safety in Schools, I G B Hall, Associate IEIE, writes:
>>
>> Furthermore it is strongly urged that all cable ends are doubled as
>>necessary and tinned to ensure good and safe contact by terminal screwe.
>>This latter practice should ensure that not only during initial assembly but
>>also during future tightening of screws (as in periodical inspection) there
>>will be no sheared strands of wire.
>>
>>Owain
>>
>>
>>
>That seems very bad advice from Mr Hall. You aren't going to get a
>"good and safe contact" onto a tinned wire in the long term.
And why not ?
>Is that a current book or some dusty tome from the distant past?
>
--
raden
Brian
"Steven Briggs" <b...@sbriggs.demon.co.uk> wrote in message
news:w4c2SnAR...@sbriggs.demon.co.uk...
I take it from that comment that appliances which are supplied from
the manufacturers where the cables are already tinned, are in fact in
your opinion unsafe?
Brian.
---
Outgoing mail is certified Virus free
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.351 / Virus Database: 197 - Release Date: 19/04/2002
Ian White
>
>I take it from that comment that appliances which are supplied from the
>manufacturers where the cables are already tinned, are in fact in your
>opinion unsafe?
>
leave the factory. Subsequent connections to the tinned ends will indeed
creep and lose contact force.
Or rather, they *weren't* tinned. These days, they leave the factory
with a moulded-on plug, precisely because of such problems.
--
Ian White
Abingdon, England
Steve Taylor
Solder or lead was used as the time delay in bomb fuses during the last
war. It DOES creep and once it starts to carry a reasonable current
creeps FAST.
Steve
Phil Addison
<st...@thetaylorfamily.org.uk> wrote:
>Solder or lead was used as the time delay in bomb fuses during the last
>war.
Amazing. Do tell how it worked.
>It DOES creep and once it starts to carry a reasonable current
>creeps FAST.
--
Phil Addison
UK.D-I-Y FAQ http://www.diyfaq.org.uk/
Dave Plowman
Brian <ag...@lycos.co.uk> wrote:
> I take it from that comment that appliances which are supplied from
> the manufacturers where the cables are already tinned, are in fact in
> your opinion unsafe?
I've seen it in the instructions for such a device that the soldered ends
must be cut off first before connecting - they were tinned only to make
testing easier.
--
* Dancing is a perpendicular expression of a horizontal desire *
Dave Plowman dave....@argonet.co.uk London SW 12
RIP Acorn
Steve Taylor
> On Sat, 27 Apr 2002 22:39:13 +0100, in uk.d-i-y Steve Taylor
> <st...@thetaylorfamily.org.uk> wrote:
>
>
>>Solder or lead was used as the time delay in bomb fuses during the last
>>war.
>
>
> Amazing. Do tell how it worked.
>
>
Better still get the book "Winston Churchill's Toyshop" By Stuart
McCrae. He was second-in-command of MIRc, a WWII organisation (based
near Aylesbury) that created special weapons (the PIAT and "sticky" bomb
amongst them)
The fuse worked by stretching a lead rod with a strong spring. The final
snap of the necked lead rod against the spring struck a sensitive
detonator. Apparently the calculation of creep required a lot of work
with every batch of lead used, but the end results were very repeatable.
These guys created the equivalent of the JP11 runway interdiction bomb
(the one that lands, stands itself up on legs, and then blows up when it
feels like it in about 1943.
Steve
Ade
Dave Plowman wrote:
>
> I've seen it in the instructions for such a device that the soldered ends
> must be cut off first before connecting - they were tinned only to make
> testing easier.
>
Plus, the stripped & tinned ends are (were) almost invariably cut to the
same length and too long to connect neatly to the plug terminals anyway,
resulting in many examples of the live conductor being tightly bent
round up the left hand side of the plug along with the neutral, or
unsheathed conductors emerging from the plug. I've never really
understood this - trimming the conductors to the correct lengths adds
virtually nothing to the time taken to wire a plug.
tony sayer
writes
Always wise to leave the Earth wire a bit longer as if the wires in the
plug come undone, if say the cable clamp fails to hold, then the earth
will be the last to go rather then the first....where it could go
wandering and find the Live!..not good...
--
Tony Sayer
Owain
| >I agree, but there are differing opinions, perhaps depending on the
| >circumstances. In the IEE Monograph "Electrical Safety at Work", Chapter
7
| >Safety in Schools, I G B Hall, Associate IEIE, writes:
| > Furthermore it is strongly urged that all cable ends are doubled as
| >necessary and tinned to ensure good and safe contact by terminal screw
| That seems very bad advice from Mr Hall. You aren't going to get a "good
| and safe contact" onto a tinned wire in the long term.
| Is that a current book or some dusty tome from the distant past?
The copyright slug is 1991. Which I suppose is 13 years ago but I'm sure I
haven't had it that long. And compared to many of my technical books, that's
modern.
It was actually IEEIE published, ISBN 0-904239-16-0
Owain
cetltd
<st...@thetaylorfamily.org.uk> writes
Or ... 1944, or 1945 ...
>
>Steve
>
--
raden
Steven Briggs
>> >
>> >
>> That seems very bad advice from Mr Hall. You aren't going to get a
>"good
>> and safe contact" onto a tinned wire in the long term.
>> Is that a current book or some dusty tome from the distant past?
>>
>> --
>> Steven Briggs
>
>I take it from that comment that appliances which are supplied from
>the manufacturers where the cables are already tinned, are in fact in
>your opinion unsafe?
>
>Brian.
>
The reasons are well understood and covered verbatim elsewhere in this
thread.
Malcolm Race
The real problem is that you could have an appliance which requires an earth
without one connected, and not know until you have a shocking experience!
Malcolm
--
Is Microsoft another name for world domination?
Hard work has a future payoff. Laziness pays off now.
tony sayer
<mr...@freeuk.com> writes
That's what I meant!..
--
Tony Sayer
Stephen Barnes
needed - just another unnecessary connection to make. And fuses always
blow, so wrap them all in tin foil before inserting them back in the
plug.....
.....I know!!!! I've been telling him for years. Mind you, the house
hasn't YET burned down.
--
********************************************
Stephen Barnes
www.blackthorndrive.co.uk
********************************************
"tony sayer" <to...@bancom.co.uk> wrote in message
news:KvbB1VAF...@bancom.co.uk...
cetltd
Barnes <stepbar999@REMOVE_ME.hotmail.com> writes
>You could adopt my father's approach to wiring plugs: the earth isn't
>needed - just another unnecessary connection to make. And fuses always
>blow, so wrap them all in tin foil before inserting them back in the
>plug.....
>
>.....I know!!!! I've been telling him for years. Mind you, the house
>hasn't YET burned down.
>
Is he related to my local newsagent by any chance ?
he recently asked me to look at his one bar fire which didn't work. He
had connected neutral to the earth pin and live to the neutral - he
obviously also thought the earth wire surplus to requirements
--
raden
Sven Franklyn Weil
Barnes wrote:
> You could adopt my father's approach to wiring plugs: the earth isn't
> needed - just another unnecessary connection to make. And fuses always
> blow, so wrap them all in tin foil before inserting them back in the
> plug.....
Yet another good reason for having manufcturers fit (or mold) the plugs
instead of end user.....
sigh....
Not observing polarity is one thing.....but bypassing the earth and having
a loose wire flapping around in there? Not smart at all...
Dave Plowman
> instead of end user.....
Oh, I dunno. Darwin awards rool....
--
*Growing old is inevitable, growing up is optional
Ian White
>In article <slrnad0n3...@gordsven.com>,
> Sven Franklyn Weil <sv...@gordsven.com> wrote:
>> Yet another good reason for having manufcturers fit (or mold) the plugs
>> instead of end user.....
>
>Oh, I dunno. Darwin awards rool....
>
But Stephen's father has already passed on his genes!
--
Ian White
Abingdon, England
New e-mail: i...@ifwtech.co.uk
Ian Johnston
<adr...@flexplugsrockroll.freeserve.co.uk> wrote:
: The reason is that solder contains lead. Lead suffers from metal creep at
: temperatures above 20 degrees. The end result of this is that joints made by
: compression (eg. screws) will work loose due to the solder creeping over
: time. This does not happen with copper since its creep temperature is over
: 100 degrees.
Copper creeps quite happily at 20 degrees. Just not very much, that's
all. And saying "solder contains lead, and lead creeps, so solder
creeps" is a bit like saying "bronze contains copper, and copper is
soft, so bronze is soft"....
Mind you, solder does creep at lowish temperatures!
Ian