2. Of angles, bending radii and the nasty leverage effect
Let’s now take a look at how far you can and may actually go with bending. In the picture below, we see a distance of about 4 cm between the bottom of the connector and the wiring harness, with the 90° bend extending from about 2 cm. You can’t really get a smaller bending radius safely unless you do it particularly skillfully (and courageously). Therefore, the variant shown in the picture can still be considered safe and is also recommended by the manufacturer.
However, there are also (let’s call them cautious) optimists who take a rather nonchalant view of bending. In order not to offend anyone or insinuate anything, I have borrowed a picture from a larger forum and anonymized it. And I also use it only as an exemplary what-happens-if example. Here, in fact, the user has managed to pull out (break out) such a crimped contact from the 12VHPWR. You can test it yourself: it really takes force to loosen the barbs by pulling straight out so that the contact is pulled out.
The bending would be rather unproblematic, if the connection was not “two-layered” and if there was not the evil leverage effect! The whole thing is very easy to recreate and can also be explained logically, especially since the user must have bent the cable at least three times. If the cables were bent downwards at a 90° angle shortly after the connector, the bending radii would be different for the two layers! The 12V lines are up here, so the radius is also larger! The cable length remains the same, however, because the sleeve and the individual cables were lashed tightly at the end with a cable tie. I have drawn a diagram that shows what could happen if you bend it several times.
Here, no cable can be subsequently tracked. But since you have to use a larger radius, it will inevitably pull the contact outward. And the closer you get to the connector, the more it will be damaged because the cables can no longer be moved next to each other in a slightly offset manner. You can also see very clearly that in the forum picture above was bent much too close to the plug and in addition several times back and forth. You can certainly do this, but then you have to break up the two layers a bit and position both the ground and the 12-volt wires rather offset from each other. You can also help yourself by tightly closing a thick cable tie behind the plug at about 2 cm and then bending it. This bending aid can be removed again after the plug has been inserted.
Conclusion and summary
I had also discussed it yesterday in the video that you MUST always bend in the NOT INSERTED STATE so that the rigid pins of the socket soldered firmly to the card do not bend up the spring sleeves as a counterpart in the plug when bending around. Because then their contact pressure decreases, the contact becomes significantly worse and the resistance increases extremely. However, if this rises significantly, then it not only gets warm, but really hot in the plug. Since the two outer leads are the most likely to move and twist, these contacts are also the most likely to be affected first.
Ergo, you should (a) generally avoid soldered solutions unless they are board-based 90° adapters (but they can introduce other problems) and (b) keep to the recommended minimum radii when bending. Anyone who thoughtlessly overlooks or consciencelessly ignores this will certainly lose. Including its hardware. Crimped cables with a decent diameter and 12 leads (6x 12 volts and 6x ground) provide exactly one lead per pin of the 12VHPWR connector, which is optimal. Anything else is and remains a dangerous temporary solution with a built-in must-break. The power supply manufacturers have known this for a while and it would have been better to ask them.
The supplied adapter belongs out of circulation, in any case. This is because a concatenation of many circumstances (breakage of solder pads and solder joints, mechanical deformations, increased contact resistances, etc.) makes it very difficult to calculate the use of such solutions with any degree of certainty. Can go well, but does not have to. And in the end, only the good Lord knows for how long. In addition, the fault pattern with the scorched connectors is also worth further investigation. Whether nylon 66 was really used or something cheaper – we will hopefully know that soon.
IMPORTANT: I am still looking for a defective, but not opened adapter (on loan), which may (but does not have to) be burnt, for detailed examinations (probably also a CT!). Please contact me as soon as possible by mail or phone (both are in the imprint). Thank you!
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