Extending cable, soldering method

[holmslaw]

..

 

[ColJack]

I didn't say his were correctly made.

 

[holmslaw]

..

 

[PrinceofDarkness]

The 'fact' is that an experienced person will know that his soldered joint is sound. It's not true to say that there's 'no way of telling'.

Crimped joints, made properly, are quite reliable. I prefer the use of uninsulated and seamless crimps. I'm not impressed with the colour-coded, insulated, cheap and nasty type - and certainly not for solid (non-stranded) cores.

The O/P wants to make a 3-way spliced-joint. He has also indicated that he's not fond of crimps and would prefer to solder. So, there isn't much wrong with that, is there?


Lucia.

 

[ColJack]

where does he say that he wants to make a 3 way splice?
he wants to cut a cable to extend it, sounds like a straight crimp to me..
perhaps he's raising a ceiling and needs extra length in the cables to remain above the ceiling ( something I had to do with around 100 singles on trunking when they installed a cold store at one job and had to raise the roof by a meter, we had to cut and crimp in an extra 2m of wire for every one of the wires in the trunking, and step the trunking too. )

 

[PrinceofDarkness]

You might be right there, Coljack, and iI might be mistaken, although the O/P. in his second post, mentioned 'three cables' - but perhaps he meant three cores of two cables?



Lucia.

 

[empip]

Knowing how you chaps love your tiny book of 'regs'.

NASA-STD 8739.4 with Change 4

...This Standard provides a baseline for NASA project offices to use when preparing or evaluating process
procedures for the manufacture of space flight hardware or mission critical ground support equipment....

4.3 Principles of Reliable Cabling and Wiring
4.3.1 Factors Controlling Reliability. Reliable interconnecting cable and wire harnesses result
from proper design, control of tools, materials, work environments, and careful workmanship by
trained and certified personnel.
4.3.2 Fabrication Principles. All fabrication shall be performed to meet governing engineering
documentation (Requirement).
4.3.3 Splicing. Splicing damaged or broken conductors is not permitted.

4.3.4 Crimping. Stranded wire shall be used for crimping (Requirement).
Crimping of solid wire is prohibited.
Crimping of solder tinned wire is prohibited.

Why does NASA prohibit crimping of solid wire?

-0-

 

[ColJack]

because crimping solid wires doesn't deform them to provide maximum surface area like stranded does.
you could end up with just the crimped points making contact..

 

[Sparklms]

I would never trust a soldered joint.

 

[PrinceofDarkness]

Well observed, empip. It's simply because the crimping of a solid cable creates a weak point on a solid conductor immediately adjacent to the joint (if the joint remains unsupported). This fact has been well documented for the last twenty years or so -- but certain electricians continue to asssert that 'crimping is best whatever the type of wire and whatever the type of crimp connector.....


Lucia

 

[mikhailfaradayski]

Going back to my apprentice days (many moons ago) my murky memory recalls that it was frowned upon to crimp solid cores. - I recall a technician/rep from Ampliversal coming to teach us shiny-overalled apprentices all the joys of crimping techniques (correct types, calibration gauging with go-no-go pins, why there are dimples in the crimp dies, all that good stuff)
I carried this thought for years.
However, it does appear as though BS7671 does not preclude crimping of solid cores so long as the crimp is not marked with an 'F', 'S' or 'sol'.

I think, in general, for any given crimp, the joint will be better on stranded than it will be on solid for reasons already mentioned (PoD, Coljack), but consideration should be given to the likely external influences experienced by the crimp to decide whether this is a problem or not.

 

[Gees]

I would never trust a soldered joint.

You had better get your crimps out and take all your electrical goods to bits and crimp all the components into the PCBs then

 

[ban-all-sheds]

Why does NASA prohibit crimping of solid wire?

"...space flight hardware...."

Slightly more arduous external influences than above Mr Smith's living room ceiling....