Crimping, A Warning
 

Hi
In a number of posts to UK DIY, people are advising the use of crimps
to join cables,
The use of insulated crimps to join solid copper conductors can cause
fire.
Their are manufacturers who will imply that their crimps will safely
join solid copper conductors, They dont.
Today I have been to my 3rd breakdown this year where a crimped cable
has broken down and caused damage.
Insulated Crimps are only for Stranded copper cable, not Solid Copper
as is found in domestic Flat Twin Cables.
Bob James

"bob" wrote in message
m...
Hi
In a number of posts to UK DIY, people are advising the use of crimps
to join cables,
The use of insulated crimps to join solid copper conductors can cause
fire.
Their are manufacturers who will imply that their crimps will safely
join solid copper conductors, They dont.
Today I have been to my 3rd breakdown this year where a crimped cable
has broken down and caused damage.
Insulated Crimps are only for Stranded copper cable, not Solid Copper
as is found in domestic Flat Twin Cables.
Bob James

Infact crimps should only be used as matched set with the tool from the same
manufacturer

So what method of joining is used if you wish to extend cables that are to
be buried/plastered over?

Phil

TheScullster wrote:
So what method of joining is used if you wish to extend cables that are to
be buried/plastered over?

Replace back to the previous joint/socket etc that's accessible ?

--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://gymratz.co.uk/hot-seat.htm - Live web-cam! (sometimes)

Pet @ www.gymratz.co.uk wrote:
TheScullster wrote:
So what method of joining is used if you wish to extend cables that
are to
be buried/plastered over?

Replace back to the previous joint/socket etc that's accessible ?

Clearly impractical in many cases. Soldering is good, but proper
mechanical support of the joint is essential, as solder is very weak.
The effective way to give this support is to twist the 2 copper wires
together for many turns. The far ends will not move relative to each
other. But insulation?

I await the day when we spot weld all joints.


NT

So what sort of crimps had been used in your cases, and how had they
been applied ? Got any photos ?

In article .com,
writes:
Clearly impractical in many cases. Soldering is good, but proper
mechanical support of the joint is essential, as solder is very weak.
The effective way to give this support is to twist the 2 copper wires
together for many turns. The far ends will not move relative to each
other. But insulation?

I do solder them. One way is to use a regular junction box
in the normal way, and then solder up the connections too.
However, this type of soldering is a skill most electricians
won't have, so I don't recommend it unless you are very
proficient at electrical soldering already.

If starting from a no skill base, teaching someone to make
reliable crimp connections using a proper ratchet crimp tool
is going to be much faster than teaching them to make reliable
solder connections. As bob has found, some people can't even
get this right (a properly made crimp won't fail in this way).

I await the day when we spot weld all joints.

Spot welding is a very skilled job, and not an accepted way
to make such connections. Brasing is the third permitted way,
but usually not practical.

--
Andrew Gabriel

wrote:

Clearly impractical in many cases. Soldering is good, but proper
mechanical support of the joint is essential, as solder is very weak.
The effective way to give this support is to twist the 2 copper wires
together for many turns. The far ends will not move relative to each
other. But insulation?

I hesitated about soldering as I vaguely remember when I had tried
soldering some solid core mains cable (for a non-mains project) the core
insulation was quickly damaged certainly beyond usability for mains
voltage applications. perhaps a higher lower melting solder might have
helped to a .... degree (or 2)


--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://gymratz.co.uk/hot-seat.htm - Live web-cam! (sometimes)

On 20 Apr 2005 15:08:15 -0700, (bob) wrote:

Hi
In a number of posts to UK DIY, people are advising the use of crimps
to join cables,
The use of insulated crimps to join solid copper conductors can cause
fire.
Their are manufacturers who will imply that their crimps will safely
join solid copper conductors, They dont.
Today I have been to my 3rd breakdown this year where a crimped cable
has broken down and caused damage.
Insulated Crimps are only for Stranded copper cable, not Solid Copper
as is found in domestic Flat Twin Cables.
Bob James

Hi,

I've always thought this, but thought I'd be in a minority of 1. I
wonder if folding the wire double and using an uninsulated crimp would
be better, so each wire gets held by the blade at each side which
would then curve into the middle.

cheers,
Pete.

On Wed, 20 Apr 2005, bob wrote:

The use of insulated crimps to join solid copper conductors can cause
fire.
Their are manufacturers who will imply that their crimps will safely
join solid copper conductors, They dont.

Insulated Crimps are only for Stranded copper cable, not Solid Copper
as is found in domestic Flat Twin Cables.

What about stranded twin & earth? It is standard for sizes 4mm^2 and above
and optional for 1.5 and 2.5mm^2.

--
Alistair Riddell - BOFH
Microsoft - because god hates us

"bob" wrote in message
m...
Hi
In a number of posts to UK DIY, people are advising the use of crimps
to join cables,
The use of insulated crimps to join solid copper conductors can cause
fire.
Their are manufacturers who will imply that their crimps will safely
join solid copper conductors, They dont.
Today I have been to my 3rd breakdown this year where a crimped cable
has broken down and caused damage.
Insulated Crimps are only for Stranded copper cable, not Solid Copper
as is found in domestic Flat Twin Cables.
Bob James

What were those plastic cap type thingys that you screw on the cables to
join them, they were all over a factory where I used to work

Regards Jeff

Pet @ www.gymratz.co.uk wrote:
wrote:

Clearly impractical in many cases. Soldering is good, but proper
mechanical support of the joint is essential, as solder is very
weak.
The effective way to give this support is to twist the 2 copper
wires
together for many turns. The far ends will not move relative to
each
other. But insulation?

I hesitated about soldering as I vaguely remember when I had tried
soldering some solid core mains cable (for a non-mains project) the
core
insulation was quickly damaged certainly beyond usability for mains
voltage applications. perhaps a higher lower melting solder might
have
helped to a .... degree (or 2)


That would help.

Maybe the insulation just isn't designed to allow the core to be
soldered.

Also (contrary to some peoples expectations) you need to use a higher
powered soldering iron and the largest bit that is suitable for the
job. That way you can get the heat in make the joint and get out again
before the insulation is damaged.

MBQ

wrote:
Pet @ www.gymratz.co.uk wrote:

TheScullster wrote:

So what method of joining is used if you wish to extend cables that

are to

be buried/plastered over?

Replace back to the previous joint/socket etc that's accessible ?


Clearly impractical in many cases. Soldering is good, but proper
mechanical support of the joint is essential, as solder is very weak.
The effective way to give this support is to twist the 2 copper wires
together for many turns. The far ends will not move relative to each
other. But insulation?


Esy. Slip heatshrink over the cables before soldering, and then slide
over the joint and shrink.

A larger bore piece goes over the complete cable.


I await the day when we spot weld all joints.


NT

Pet @ www.gymratz.co.uk wrote:

wrote:

Clearly impractical in many cases. Soldering is good, but proper
mechanical support of the joint is essential, as solder is very weak.
The effective way to give this support is to twist the 2 copper wires
together for many turns. The far ends will not move relative to each
other. But insulation?


I hesitated about soldering as I vaguely remember when I had tried
soldering some solid core mains cable (for a non-mains project) the core
insulation was quickly damaged certainly beyond usability for mains
voltage applications. perhaps a higher lower melting solder might have
helped to a .... degree (or 2)


Hotter iron helps. Takes less time to make the joint.

In article ,
"Jeff" writes:

What were those plastic cap type thingys that you screw on the cables to
join them, they were all over a factory where I used to work

"Screwits" is one brand name. A nicname they had back in the
days they were used was "dog ********" due to the way a pair
of them would hang down below a cable. They are still allowed
and commonly used in the US, who call them wire nuts, and are
a significant source of building fires.

Note that there are crimps which look similar too.

--
Andrew Gabriel

In article , Jim Michaels
writes

Wire Nuts when properly installed do NOT overheat!

Aluminium wiring is common in the USA. When aluminium wiring is
combined with wire nuts, overheating and fires result.

http://www.inspect-ny.com/aluminum/ja-54.jpg
http://www.inspect-ny.com/aluminum/fr1-hotbox.jpg

It should be noted that US wiring codes require ALL splices to be in
junction boxes. If a mis-applied wire nut were to overheat and start
the insulation on fire, it would be contained and not lead to a
structure fire.

That's by no means clear, according to the above website. This sequence
of photos make it clear it's possible for fires to travel along the wire
insulation and out of the junction box, possibly spreading to the house
structu

http://www.inspect-ny.com/aluminum/pl2p13.htm

Jim Michaels wrote:

It seems strange that many otherwise enlightened people persist in
believing cross Atlantic stereotypes.

As in all things American associated with building construction - they
only make it quicker and cheaper to build, apart from that they offer
nothing.


--