Dull wiring question

Both various iterations of the same nonsense.

IDC are often used on ribbon cables or multiple core cables, usually in some form of data transfer.

Ok in a nice, warm dry pc case or other enclosure, but useless in any 'environmental' capacity.

Not used in aircraft. We have a pin crimped onto the end of every core, then these are bundled together into MIL-spec connectors.

IDC has no place where vibration or moisture are present, neither do chocolate blocks.
 
rosssavage said:
Both various iterations of the same nonsense.

IDC are often used on ribbon cables or multiple core cables, usually in some form of data transfer.

Ok in a nice, warm dry pc case or other enclosure, but useless in any 'environmental' capacity.

Not used in aircraft. We have a pin crimped onto the end of every core, then these are bundled together into MIL-spec connectors.

IDC has no place where vibration or moisture are present, neither do chocolate blocks.
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So what's the difference between crimped, a crimped IDC and a Scotchlok?
 
I am going to make a plea not to condemn all chocolate block type connectors.

There are some (and I mean a very few) that are either stainless or plated brass (not the plated steel ones that eventually go rusty and cacky and produce duff joints!).

The ones I have used don't rely on the screw compressing the wire, but had a tiny sprung plate inside the connector that the screw presses on and compresses the wire against the bottom of the connector block. All brass or stainless and very good quality.

I try not to use them, and I can't find a reference, but there is one for our Navtex interface screwed to the back of my switch panel. No corrosion and very good connections.

I can't find a source or reference for where to buy them though.
 
elton said:
So what's the difference between crimped, a crimped IDC and a Scotchlok?
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The difference between properly crimped and scotch/IDC is a mechanical, and hence electrical one.

In a (properly) crimped connection all of the insulation is removed from the conductor. The conductor makes a full 360 deg contact with the terminal, and is mechanically held in place by the action of crimping the connector onto the conductor.

Real crimps also clamp down on the insulator of the conductor to provide cable strain relief, although admittedly these are rarely seen on boats.

Environmental grade crimps also include a heat activated sealant in the strain relief portion of the crimp, which is activated by a heat gun after assembly to provide some envrionmental protection. Used frequently in areas not fully protected - such as in the leading edges of B737's to connect to slat position sensors.

IDC's, however, rely on two edges of the parent conductor being squeezed into the gap of the IDC crimp, having the action of both cutting the insulation to a predetermined depth and squeezing the conductor into the 'teeth' of the IDC for an electrical connection.

There is no positive way to determine how effective the cutting action of the IDC crimp has been on the insulation of the parent conductor - this is perhaps testable with a multimeter etc.. but cannot determine if the joint is sufficient to carry the design current.

Further, a scotchlok is free (mechanically) to move around the conductor and cut or damage the core as there is no mechanical support. This can promote damage and even sever the conductor.

There is no environmental protection whatsoever.

I can go into more detail later, but I'm at work and apparently I should be 'doing' something.... :)
 
Ubergeekian said:
Scotchloks are designed to attach the end of one wire to the midpoint of another, which is not quite the same thing. They are also a god-awful bodge which should have no place on any respectable wiring system.
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Scotchlocks are terrible items. Only for use as an emergency bodge.
 
Elton

The anatomy of a proper crimp is shown in detail here, as well as how to make them. http://www.pbase.com/mainecruising/wire_termination

rosssavage

The only kind of crimps I use also clamp the insulator.

I either use the kind with heatshrink on them or use separate heatshrink. On all connections in a boat.

The most interesting part of my job is seeing how the manufacturer has taken shortcuts. I can recall very few boats without them, regardless of price.
 
mitiempo said:
Elton

The anatomy of a proper crimp is shown in detail here, as well as how to make them. http://www.pbase.com/mainecruising/wire_termination

rosssavage

The only kind of crimps I use also clamp the insulator.

I either use the kind with heatshrink on them or use separate heatshrink. On all connections in a boat.

The most interesting part of my job is seeing how the manufacturer has taken shortcuts. I can recall very few boats without them, regardless of price.
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It makes a good case for soldering rather than crimping. There are so many ways to make a bad crimp, and an undetectably bad crimp at that. And you need the right tools to get it right. The quality of a soldered joint can be determined by eyesight. You can even make a good soldered connection using just a cigarette lighter, as long as you also have teeth and resin cored solder at hand.
 
With the right tools and the right connectors a proper and consistent quality crimp is easy. Much faster as well.

ABYC states in E-11 that solder may not be the only connection - so it would have to be crimped as well. Soldering doesn't work on a good connector like those in the link. And if you have a good crimp the solder adds nothing beneficial.
 
mitiempo said:
With the right tools and the right connectors a proper and consistent quality crimp is easy. Much faster as well.

ABYC states in E-11 that solder may not be the only connection - so it would have to be crimped as well. Soldering doesn't work on a good connector like those in the link. And if you have a good crimp the solder adds nothing beneficial.
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If you solder properly you don't need a crimp. How do you check a crimped connection for integrity and quality? ABYC doesn't mean anything here.
 
It does if you are trying to meet their wiring standards. They are the standards in North America and there is a move afoot for them to become worldwide. It has a lot of support from both sides I understand. The advantage is a given builder's market would be expanded, making it easier to export boats from Europe to North America or from here to Europe.

I try to meet their standards on all wiring jobs I do or am a part of.
 
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mitiempo said:
It does if you are trying to meet their wiring standards. They are the standards in North America and there is a move afoot for them to become worldwide. It has a lot of support from both sides I understand. The advantage is a given builder's market would be expanded, making it easier to export boats from Europe to North America or from here to Europe.
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I wouldn't object to crimping by a manufacturer, but I wouldn't let any sparky near my electrics with one. As I said, there's no way to check the integrity of a crimped union; at least none that I'm aware of. And as your link showed, there are many ways to make a dodgy one.
 
Sometimes I make well over a hundred crimps a day, from 16awg to 2/0, and they are consistently good. I think that with the proper tools and a little experience that crimps are much more consistent than many soldered connections.
 
And with the proper care the connections are always good.

There are those with a lot of experience soldering that are able to achieve good joints time after time. But the instances I have seen on boats - by the manufacturer or owner - leave a lot to be desired.


Boeing and any airplane manufacturer I know of use crimps, not solder.
 
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The solder debate I'd like to know more on (even given the fact I know and trust crimps).

As I understand it solder connections can succumb to vibration more than crimp connections do, but I cannot find any references directly relating to accelerated corrosion etc caused by normal solder products.

Anyone know otherwise?
 
There is not any reason a soldered joint will corrode any faster than a crimped joint. If properly covered with adhesive heat shrink they should last many years if not a decade or two - both of them.
The commonly stated problem with solder is vibration or movement as the wire transitions from the soldered section to flexible wire.

Probably the main reason airplane makers use crimps.

If you do solder, resin core has to be used, not acid core.
 
That makes sense then, as I suspected - my experience/background is automotive electronics not marine so I'm just getting used to the differences.

You don't see any crimps other than within AMP connectors etc. Interconnections within looms tend to be soldered or crimped & Soldered, and some makers will cover the soldered connections with a non setting water resistant sealant then cover with tape. Others just tape.
 
I have recently completed a marine electrical installers course and they don't approve of soldering - it seems that the solder is capable of melting if the wire is overloaded?

We use marine grade cable and heatshrink connectors for all of the wiring on the race boats and they are all the glue and heatshrink type. We never use scotchlocks or chocolate blocks as they have no place on a boat IMHO.
 
elton said:
Scotchlok connectors are designed specifically for joining 3 wires. As long as you use the right size connector for the wire you can't go wrong.
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What I find slightly odd is that you seem to be happy with scotchloks but apparently won't let a spark near your boat with crimps....

Next time you fly, be assured that there are no scotchloks and maybe a few thousand crimped connections making that aircraft fly. There is a reason for that!

Beyondhelp: yup, AMP good. That'll be Aircraft Marine Products :)

Raychem also make high grade crimps and tools.

Soldering is used on aircraft, but not for anything important - cabin equipment and furnishings etc...

As mentioned previously, it is a poor mechanical solution in high vibration environments - it is hard and cracks.
 
rosssavage said:
What I find slightly odd is that you seem to be happy with scotchloks but apparently won't let a spark near your boat with crimps....

Next time you fly, be assured that there are no scotchloks and maybe a few thousand crimped connections making that aircraft fly. There is a reason for that!
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Several reasons for my choice:

  • I have a boat, not an aircraft.
  • I wouldn't trust an unknown electrician to use the right tool for the crimps.
  • Every piece of electronic equipment I own has hundreds of components soldered together. None of them are crimped.
  • I can visually inspect a soldered connection and verify its integrity. I can't do the same with a crimp.
  • Factory assembly employs a strict QC regime, which does not apply to in-service add-ons and modifications.
I do wonder how many of those expressing an opinion on this subject have any practical experience.
 
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