Ferrules Falling Out

For the whole season of Deep Space our team has been experiencing connection issues with our 18 gauge wires coming loose from the PDP, VRM, and PCM. We were crimping ferrules onto them with a square crimper that leaves ridges but since they were easily coming out by just tugging on them, we switched to just inserting the bare wire which seemed to stay in quite well. Is there a better practice for this? Correct size and type of ferrules? Best shape of crimper? Ridged crimping versus smooth?

Thank you

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How long are your ferrules?

Ferrules can work well, if done right… but I’ve seen way too many teams have issues with them to ever use them myself. A little care and attention when inserting bare wires is all it really takes (just to make sure you don’t have any whiskers or strip an incorrect amount of insulation off), and it stays in rock solid.

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We have developed an interesting technique. I’m not sure why it works, but it seems to work and give us the best of both worlds:

When crimping the ferrule onto the wire, we strip back the insulation long enough to actually have the wire extend out the other end of the ferrule by 1/8" - 1/4" and then crimp it. The wire clamp inside the PDP, VRM, etc seems to like to grab the bare wire sticking out the end and gives a very solid hold. But, by having the ferrule on the wire, you get the protection against whiskers and an extra layer of separation between the red and black wires so that you won’t have inadvertent shorting. It also gives a nice way to grab the wire to insert it into the device.

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Is the wire coming out of the ferrule (ferrule stays in place) or the ferrule coming out of the connector?

If wire is coming out of ferrule, then are you sure you are using he correct gauge and length ferrule? When you crimp the ferrule, make sure the wire strands stick out the end before crimping. Then trim off excess - that guarantee’s full engagement.

If Ferrule is coming out of connector (still attached to the wire) then make sure the ferrule you are using is the appropriate length and is getting fully engaged by the connector.

Also make sure the connector isn’t shot - they can get worn and allow ferrules to slip out. Give the wire a good tug to make sure the connection is secure.

Check out this video on using ferrules: https://www.automationdirect.com/videos/video?videoToPlay=oN-tps_HEj0&q=ferrule

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The simple, legal, and safe solution works well for you, the more expensive, more time consuming technique does not. Sounds like a no brainer to me; just watch out for whiskers.

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Having messed around with ferrules for a little while now, this seems to be the most common factor in whether the ferrule is able to be pulled out or not.

One of those times, when I read something and realize I should have thought of that a long time ago. This is especially useful for when teams have ferrules that are a bit too short. Thanks for the tip.

MahiMahi,
This is an unusual situation. Ferrules work fairly well when used with the proper strip length and crimp tool. There is a great video on the CTRE website showing crimp and strip methods. If the ferrule is the one pulling out of the VRM and other devices, it is most often not fully inserted. If the wire is pulling out of the ferrule, it is very likely that the strip length is too short. It must be about 3/8" of an inch. As other have stated, stripping it long enough to stick out and then trimminng after the ferrule is crimped is perhaps the best method.

The ferrule may be for the next larger wire range.

We’ve experienced similar issues with ferrules this year. We haven’t decided what out plan is going forward, but I find that flattening ferrules with pliers after using the ferrule crimper can help keep them smaller and stick better in the connectors.

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