Thread: Joining electrical wire, solder, spades or blocks?

Originally Posted by njz

What does everyone think of solder splice terminators? I've always used crimp terminals but these look Stoopidly dear.

Just a little edit

Having been an installation techo in a past life...

if its permanent, then its a solder and heatshrink...

if it needs to be disconnected then I use various connectors for crimping, fortunately I still have a very expensive crimp tool

BTW, If anyone wants cable, I have many kilometres of varying types and grades... I really should catalog it all and put in the markets area shouldn't I?.......

GQ

Originally Posted by JohnE

THAT's why you don't use them - they inevitably cause problems. And, according to Murphy's Law, the problems will always be at the most inconvenient times and locations.

thanks but, you haven't explained why?


john[/quote]

My take on it : Scotchblocks rely on a 'V' shaped notch in a thin piece of metel to cut through the insulation of the wire when crimped, and then maintain contact with the wire. Because the contact area is very small, ( just the edges of that V ) it is easy to get a poor contact if water/dirt gets in there or the wire works a bit loose. The worst things ever invented - so bad they they could have been invented by LUCAS :-) . Auto leccys use them because they are quick and convenient, but any auto leccy worth thier salt wouldn't touch them.

Originally Posted by waynep

thanks but, you haven't explained why?


john

My take on it : Scotchblocks rely on a 'V' shaped notch in a thin piece of metel to cut through the insulation of the wire when crimped, and then maintain contact with the wire. Because the contact area is very small, ( just the edges of that V ) it is easy to get a poor contact if water/dirt gets in there or the wire works a bit loose. The worst things ever invented - so bad they they could have been invented by LUCAS :-) . Auto leccys use them because they are quick and convenient, but any auto leccy worth thier salt wouldn't touch them.

Yep - what he said. The connection is poor and the least bit of corrosion, dust or movement can break it, creating a "dry joint." Is any Land Rover completely free of corrosion, dust or movement? The short-term sollution if one plays up is to give the joint a good wriggle. The cure though is to not use them.

a little bit of knowledge is a dangerous thing.
scotchlocks are fine when used for the purpose for which they were designed. those plastic cable splicing connectors we get from spares places are not scotchlocks. the real scotchlocks are a small clear plastic device with two or more sized holes in it. it has a water resisting gel in it and when you put your data or telephone cables into it, you squash the centre button in which locks the wires into the connection.
what you need depends on what you are connecting and whether you want to get it apart again.
stereos and anything else that goes in the dash is usually fine with any push-together connector, beit spades, bullets, harness plugs or whatever.
if it is going to get wet and you want it to stay together and not oxidise, like a trailer plug socket, solder and heatshrink it, but you have to use the heatshrink with the layer of hot-melt glue in it. that way it will seal the join. if you are going to solder it, it is best to use crimp tunnel type lugs then solder them.
this is all well and good of course, but you also have to consider the size of the cable and it's current rating and use the right size lugs or joiners.
if the cables don't fit in the lug or joiner, don't give it a haircut, use a bigger lug, they are sized in respect to current rating (different for AC and DC for the same size cable and for flexible and non flexible cable)

Originally Posted by waynep

thanks but, you haven't explained why?


john

My take on it : Scotchblocks rely on a 'V' shaped notch in a thin piece of metel to cut through the insulation of the wire when crimped, and then maintain contact with the wire. Because the contact area is very small, ( just the edges of that V ) it is easy to get a poor contact if water/dirt gets in there or the wire works a bit loose. The worst things ever invented - so bad they they could have been invented by LUCAS :-) . Auto leccys use them because they are quick and convenient, but any auto leccy worth thier salt wouldn't touch them.[/quote]


Thanks wayne that explains it better than, ' they inevitably cause problems'.


I don't know how 3M goes though, found this earlier on, their web site, at least i know the principle, says they are resistant to moisture.




With 3M™ Insulation Displacement Connectors (IDC), simply insert unstripped wires into this durable little plastic connector and squeeze to make a reliable connection. The “U” element bites through the insulation to make contact with the wire conductors inside without damaging the cable.
3M invented IDCs and makes them for electrical and telecommunications, including applications that require resistance to moisture, solvents or flame. 3M also offers special tools designed to make applying IDCs even easier. They’re excellent for making connections for vehicles and boats, recreational vehicles, lighting and control and communication circuits.



Don't see any warnings , about them failing.



john

"Thanks wayne that explains it better than, ' they inevitably cause problems'."

It does But then, I hadn't seen your request for more info until later. I had thought the "dry joint" comment was sufficient. On re-reading, I see it was unclear.

On alternative approaches - the Army trailer and vehicle both have banks of screw-tightening clamps taking the wiring from the vehicle and adapting for a plug and vice versa. I've had these give problems (with wiring falling out or connections failing due to corrosion and mud) but they are easily fixed with a screwdriver.

Originally Posted by barney

a little bit of knowledge is a dangerous thing.
scotchlocks are fine when used for the purpose for which they were designed. those plastic cable splicing connectors we get from spares places are not scotchlocks. the real scotchlocks are a small clear plastic device with two or more sized holes in it. it has a water resisting gel in it and when you put your data or telephone cables into it, you squash the centre button in which locks the wires into the connection.
what you need depends on what you are connecting and whether you want to get it apart again.
stereos and anything else that goes in the dash is usually fine with any push-together connector, beit spades, bullets, harness plugs or whatever.
if it is going to get wet and you want it to stay together and not oxidise, like a trailer plug socket, solder and heatshrink it, but you have to use the heatshrink with the layer of hot-melt glue in it. that way it will seal the join. if you are going to solder it, it is best to use crimp tunnel type lugs then solder them.
this is all well and good of course, but you also have to consider the size of the cable and it's current rating and use the right size lugs or joiners.
if the cables don't fit in the lug or joiner, don't give it a haircut, use a bigger lug, they are sized in respect to current rating (different for AC and DC for the same size cable and for flexible and non flexible cable)

..and and on this site you can always rely on someone with a lot of knowledge to pipe up and correct us
...yep I guess we are all referring to those "elcheapo" plastic connectors you buy from the auto places ...but from the info on 3M's website it seems the genuine "Scotchlock" is a better designed unit....