Do/Don't? Soldering Wire Tips Before Sticking into Terminal Block

[D from BC]

Is it ok to solder the tips of stranded wire before inserting into a
terminal block?
I like soldering the tips so that there's no wire fraying or free
strands.
But...Does the solder slowly compress after awhile and the wire gets
loose?
Sure I could perhaps a crimp on pin terminals to stick in the terminal
block.
Ex:
http://www.molex.com/pdm_docs/sd/192110001_sd.pdf
I'm afraid I'll have to buy a ridiculously priced crimping tool that'll
get used a few times and then be forgotten.

 

[Martin Riddle]

Is it ok to solder the tips of stranded wire before inserting into a
terminal block?
I like soldering the tips so that there's no wire fraying or free
strands.
But...Does the solder slowly compress after awhile and the wire gets
loose?
Sure I could perhaps a crimp on pin terminals to stick in the terminal
block.
Ex:
http://www.molex.com/pdm_docs/sd/192110001_sd.pdf
I'm afraid I'll have to buy a ridiculously priced crimping tool
that'll
get used a few times and then be forgotten.

Yes the solder will cold flow.

There are other crimp terminals such as Panduit
<http://www.alliedelec.com/search/productdetail.aspx?SKU=3810879>
These can use standard lug crimpers.

Cheers

 

[D from BC]

Yes the solder will cold flow.

There are other crimp terminals such as Panduit
<http://www.alliedelec.com/search/productdetail.aspx?SKU=3810879>
These can use standard lug crimpers.

Cheers

Does that apply to all solders?
Is there a type of solder that takes a longer time to cold flow?
Silver solder?

 

[D Yuniskis]

Is it ok to solder the tips of stranded wire before inserting into a
terminal block?
I like soldering the tips so that there's no wire fraying or free
strands.
But...Does the solder slowly compress after awhile and the wire gets
loose?

If you are going to put a (bare) wire under a screw, put that
*bare* wire under the screw. Don't "tin" it.

I think there are even some safety regulations that directly
address this issue (?)

 

[Martin Riddle]

Does that apply to all solders?
Is there a type of solder that takes a longer time to cold flow?
Silver solder?

Not sure, but I have come across this failure before.

Cheers

 

[Ban]

Is it ok to solder the tips of stranded wire before inserting into a
terminal block?
I like soldering the tips so that there's no wire fraying or free
strands.
But...Does the solder slowly compress after awhile and the wire gets
loose?
Sure I could perhaps a crimp on pin terminals to stick in the terminal
block.
Ex:
http://www.molex.com/pdm_docs/sd/192110001_sd.pdf
I'm afraid I'll have to buy a ridiculously priced crimping tool
that'll get used a few times and then be forgotten.

ferrules an a hand crimping tool can be found for a few bucks at Walmart.
The solder makes the strands brittle and if there is some vibration the
cable will break off. solder migration is not an issue here.

Ban

 

[Tim Watts]

Is it ok to solder the tips of stranded wire before inserting into a
terminal block?
I like soldering the tips so that there's no wire fraying or free
strands.
But...Does the solder slowly compress after awhile and the wire gets
loose?
Sure I could perhaps a crimp on pin terminals to stick in the terminal
block.
Ex:
http://www.molex.com/pdm_docs/sd/192110001_sd.pdf
I'm afraid I'll have to buy a ridiculously priced crimping tool that'll
get used a few times and then be forgotten.

2 problems:

1) Solder "creeps" over time, so the screw that was tightened today may not
remain tight.

2) IME, I have also observed, with finer wires, that the wire can break at
the point between tinned and non tinned wire due to concentration of
stresses.

The right way is to crimp some "bootlace" uninsulated ferrules on the end,
which is what I do with house wiring, if I'm terminating flex from say 12V
downlighters (I use silicone HT flex for the last leg to these) into regular
terminal blocks. Works very nicely. Don't buy the crimp tool from RS unless
you like throwing money away - a little research on google and you can get
decent ratchet tools for 20-30 quid. The ferrules are dirt cheap.

 

[Tim Williams]

Does that apply to all solders?
Is there a type of solder that takes a longer time to cold flow?
Silver solder?

Silver solder is actually a braze, and as such you will have no insulation
left on the wire after brazing it. It's made of similar metals as the wire,
so it won't cold flow, not at this temperature anyway.

Tim

 

[Fred Abse]

solder migration is not an issue here.

No, but "creep", in the metallurgical sense (slow deformation under
stress), is. The solder filling the interstices between individual wires
moves, allowing the connection to go slack.

 

[Fred Abse]

Does that apply to all solders?
Is there a type of solder that takes a longer time to cold flow? Silver
solder?

If you mean tin/lead/silver solder, the sort that you can use an iron
with, that's as bad as ordinary tin/lead.

"Proper" silver solder, AKA hard solder, doesn't creep as much, but needs
a brazing torch.

 

[Rich Webb]

Is it ok to solder the tips of stranded wire before inserting into a
terminal block?
I like soldering the tips so that there's no wire fraying or free
strands.
But...Does the solder slowly compress after awhile and the wire gets
loose?
Sure I could perhaps a crimp on pin terminals to stick in the terminal
block.
Ex:
http://www.molex.com/pdm_docs/sd/192110001_sd.pdf
I'm afraid I'll have to buy a ridiculously priced crimping tool that'll
get used a few times and then be forgotten.

As others have mentioned, solder-tinning the ends is contra-indicated;
the solder will cold flow or crumble and the connection loosen.

Either just use the bare (twisted) wire ends or (preferred) crimp a
ferrule over the bundle. I use the ones from
http://www.americanelectrical.com/wireferrules.htm. Not too expensive
and Digikey (and others) carry several of their kits/assortments.

For the crimper, if you have a compatible frame then you can get a set
of dies pretty cheaply. If you need the whole setup, try a Lunar frame +
die set p/n 300-001 at http://www.starkelectronic.com/eclp8.htm among
others.

 

[nospam]

Is it ok to solder the tips of stranded wire before inserting into a
terminal block?

No.

The 'spring' in what you screw down on is what maintains pressure on the
screw threads and so maintains friction to prevent the screw turning.

Compare the 'springiness' of a bit of solder with a similar bit of copper
wire and why it is a bad idea is obvious (and the copper will work harden
and become even more 'springy').

If you really don't want to use ferrules a dab of solder right on the end
will hold the strands together while keeping just copper under the screw
but it is hard to achieve consistently.

 

[D Yuniskis]

If you really don't want to use ferrules a dab of solder right on the end
will hold the strands together while keeping just copper under the screw
but it is hard to achieve consistently.

A friend used to (haven't seen him in decades so no idea
if he ever "learned better" :>) part the strands into
two groups. Then, slip the screw between the groups.
Finally, twist the groups together on the "far side"
of the screw. I.e., the screw is now captive to the
wire.

This made it easy to attach wires in often hard to reach
places -- but it was just *so* wrong in so many ways! :<
(copper on the "right" side of the screw ends up being pushed
out of the way as the screw is tightened)

[hmmm... that begs the question: what term to use
to refer to describe the "side" (direction) that you
turn *into*? E.g., what I have called "right" in
this example]

 

[D Yuniskis]

nospam wrote:

[hmmm... that begs the question: what term to use
to refer to describe the "side" (direction) that you
turn *into*? E.g., what I have called "right" in
this example]

The side into the wind would be "windward" side, so the other side
would be "leeward". ;-)

wise *ss! :>

My question is serious: how do you refer to the "clockwise
side" of something? etc.

 

[D from BC]

nospam wrote:

[hmmm... that begs the question: what term to use
to refer to describe the "side" (direction) that you
turn *into*? E.g., what I have called "right" in
this example]

The side into the wind would be "windward" side, so the other side
would be "leeward". ;-)

wise *ss! :>

My question is serious: how do you refer to the "clockwise
side" of something? etc.

My GPS says 'Keep right'
or
'Keep left'.
Maybe that can apply here.

 

[D Yuniskis]

Hi Joe,

nospam wrote:
[hmmm... that begs the question: what term to use
to refer to describe the "side" (direction) that you
turn *into*? E.g., what I have called "right" in
this example]
The side into the wind would be "windward" side, so the other side
would be "leeward". ;-)

wise *ss! :>

My question is serious: how do you refer to the "clockwise
side" of something? etc.

CW to the right, CCW to the left. In 2-D algebraic geometry CW is
negative angular displacement and CCW is positive.

Yes, I know CW from CCW. :>

What I was getting at is how do you concisely (ha! me and concise,
what an idea! :> ) refer to the situation I was describing above.

I.e., you wrap a wire around a screw/post clockwise so that
tightening the screw draws the wire around the screw *with*
the screw's motion. How do you describe the "initial placement"
of said wire? I.e., it wants to be "to the left" <frown>
of the post (but left and right have no meaning in this
context; and clockwise/counterclockwise only refer to
the direction in which you *wrap* the wire -- not *place* it!)

For example, placing the wire such that tightening the
screw *frays* the individual strands is A Bad Thing.
How do you refer to the "side" of the screw that causes
this result? (without saying "wrap the wire around the post
in a clockwise manner" -- since some wires are NOT
wrapped around a post ... e.g. solid wire that under some
sorts of connectors)

As an aside, I recently noticed a Hubbel (?) power plug
had a guide for *insulation* length as well as "stripping
length" molded into the plastic. I'd seen the latter
in many places before. But, this was a first for the
former! (turned out to be "spot on", too!)

 

[D Yuniskis]

nospam wrote:
[hmmm... that begs the question: what term to use
to refer to describe the "side" (direction) that you
turn *into*? E.g., what I have called "right" in
this example]

The side into the wind would be "windward" side, so the other side
would be "leeward". ;-)

Which leads to a common sailor's problem: it is preferred that the
movable ballast (passengers) sit on the windward side, but piss off
the leeward.

Simple: just carry "well hung" pasengers! ;-)

 

[Paul Keinanen]

Is it ok to solder the tips of stranded wire before inserting into a
terminal block?
I like soldering the tips so that there's no wire fraying or free
strands.
But...Does the solder slowly compress after awhile and the wire gets
loose?
Sure I could perhaps a crimp on pin terminals to stick in the terminal
block.

I would never solder a multi stranded wire protected by a 6-16 A mains
fuse.

If there is a shot circuit, the current could be something like 50-100
A, creating a lot of heat in a bad junction, heating the soldered wire
ends and deforming the wire.

After replacing the fuse, there would be a bad connection creating a
significant amount of heat.

If the mains fuse is blown, at least check each screw terminal for bad
connections.

 

[Tim Williams]

[hmmm... that begs the question: what term to use
to refer to describe the "side" (direction) that you
turn *into*? E.g., what I have called "right" in
this example]

Angular directions are most specifically denoted by the right hand rule.
Point your thumb in the direction of the axis, and your fingers will curl
around the direction of positive rotation.

The problem then becomes specifying the 'thumb vector' consistently, but
that's a bit easier now since "into the surface" is true no matter what
direction you're looking at it (whereas the rotation is reversed if you flip
the axis!).

Tim

 

[D Yuniskis]

Hi John,

Hi Joe,

[email protected] wrote:
nospam wrote:
[hmmm... that begs the question: what term to use
to refer to describe the "side" (direction) that you
turn *into*? E.g., what I have called "right" in
this example]
The side into the wind would be "windward" side, so the other side
would be "leeward". ;-)
wise *ss! :>

My question is serious: how do you refer to the "clockwise
side" of something? etc.
CW to the right, CCW to the left. In 2-D algebraic geometry CW is
negative angular displacement and CCW is positive.

Yes, I know CW from CCW. :>

What I was getting at is how do you concisely (ha! me and concise,
what an idea! :> ) refer to the situation I was describing above.

I.e., you wrap a wire around a screw/post clockwise so that
tightening the screw draws the wire around the screw *with*
the screw's motion. How do you describe the "initial placement"
of said wire? I.e., it wants to be "to the left" <frown>
of the post (but left and right have no meaning in this
context; and clockwise/counterclockwise only refer to
the direction in which you *wrap* the wire -- not *place* it!)

For example, placing the wire such that tightening the
screw *frays* the individual strands is A Bad Thing.
How do you refer to the "side" of the screw that causes
this result? (without saying "wrap the wire around the post
in a clockwise manner" -- since some wires are NOT
wrapped around a post ... e.g. solid wire that under some
sorts of connectors)

No, you're still missing the distinction! The direction the wire
*approaches* the screw from plays a role. E.g., Red Right Return
is different from Red Right Depart! :>

So, you have to think in terms of the tip of the wire in
relationship to the balance of the wire. I.e., if you are standing
at the tip WITH THE REST OF THE WIRE BEHIND YOU, then your approach
to the screw would keep *it* on your right. If, OTOH, you were
standing at the tip with the balance of the wire IN FRONT of you,
then you would keep the screw on your left.

Or, from your analogy, whether the wire approaches you (standing
on the head of the screw) "head on" or creeps up on you from behind.

There are two references here -- how you refer to the wire
and how you refer to the screw (post).

Think of how you would explain this to "a guy off the street"
(not someone in s.e.d)