Author Topic: Tinned wire ends in ferrules?  (Read 2305 times)

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Offline SpannersToSparksTopic starter

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Tinned wire ends in ferrules?
« on: September 04, 2019, 02:22:45 pm »
Hi

Out of habit I tinned the end of some wires that will see only milliamps (they are connected to some load cells) and 5-10V. They connect to screw terminals.

However, as there were ferrules on hand I wondered about adding them, but noticed the packet says "stranded wire only".

Would using ferrules with tinned wires present a problem? I can always just strip back if needs be.
 

Offline Zero999

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Re: Tinned wire ends in ferrules?
« Reply #1 on: September 04, 2019, 03:05:29 pm »
I believe it's bad practise to use tinned stranded wire in screw terminals. Tinning the wire makes it more brittle and prone to breaking.

As far as ferrules are concerned: no, never tin the wire and the same is true for any crimped connection. Again it makes it more brittle and the solder reduces the crimp's grip, as it is slowly flowing and provides some lubrication.
 
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Offline Gyro

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Re: Tinned wire ends in ferrules?
« Reply #2 on: September 04, 2019, 04:18:31 pm »
It's not just a matter of making the wires brittle (where the soldered together strands transition to the free ones, often under the insulation). The solder will easily cold-flow over time, removing a lot of the clamping screw pressure.

This is much more of an issue for higher current connections, but can still cause unstable connections at low current.

Crimped ferrules (on non-tinned wire ends) are an excellent way of terminating stranded wires for use in terminal strips.
Best Regards, Chris
 

Online ejeffrey

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Re: Tinned wire ends in ferrules?
« Reply #3 on: September 04, 2019, 04:49:55 pm »
++

Screw terminals on plain stranded or solid core wire is fine, tinning is unnecessary and counterproductive.  Crimped ferrules are a nice way to terminate stranded wire especially if it will be reconnected frequently, but are not necessary, although I strongly prefer them at high current.  Crimping is also nice if the terminal pitch is tight as it keeps stray strands from shorting out to neighboring contacts.
 

Offline SpannersToSparksTopic starter

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Re: Tinned wire ends in ferrules?
« Reply #4 on: September 05, 2019, 07:42:50 am »
Thanks everyone, that's exactly what I need
 


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