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Preview: Boat Wiring, Part 4 – Making Good Connections

March 20, 2013

Don Eley shows us which connectors to use and how to crimp and connect them in this boat wiring video.

Watch Boat Wiring, Part 5 – Over-Current Protection or…

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– [Narrator] Today in our series on marine electrical systems, Don Eley gets us into terminal end-fittings and foolproof ways to make them last.

– [Don] What we’re trying to accomplish here is match the size of the barrel in the connector to the appropriate gauge of wire so that when we crimp this down, we have a good crimp. Connector terminal end colors are matched to wire gauge, so 10 and 12 gauge wire, we use yellow, 14/16 gauge wire we’re going to use blue terminals. This is just a convention that’s there, and when we get down to 18 gauge or 20 gauge wire, we’re going to use red terminals, regardless of the wire color. Connectors are not designed to match the wire. In this particular case, the yellow is with the yellow but if we use this on too small of a gauge of wire, what we’re going to find is that doesn’t fill that barrel arrangement fully and when we crimp it, we don’t get a good connection. First thing we’re going to do is we’re going to strip the insulation off the end of the wire so that the wire will fit up into the barrel of the terminal for crimping, and we’ve got a couple of different tools here that we can do that with. The first ones I’m going to introduce you to are the ones that we’re going to use to strip the wire, and in this particular arrangement here, you can see the wire gauge is listed over here on the right hand side, and we’re going to be stripping 10 gauge wire first. It’ll actually give us the amount we should strip depending on what we’re stripping. And so we’ll put this into the 10 gauge, we can squeeze down on that, rotate it a little bit, and then give it a pull, and we’ve stripped the insulation off the wire. What’s really important there is we use the correct stripping arrangement so that we don’t break any of the fine strands off. You can see none of the strands are left in the insulation. We have all the strands left here, I like to give it a little twist like that, and now we’re ready to crimp it. And I’ve got a couple of different crimp ins that we’re going to look at. One is again, a standard nylon crimp-in. You look right through the end of it and we insert the wire in there, and the wire you can actually see, there it is coming out the end of it, and then we would crimp this particular end. This is a heat shrink end, and the wire doesn’t stick all the way through. It’s sealed with this heat shrinkable casing. In that case, we’re going to insert it into the terminal end, and then we’ll crimp it also but notice that the end of the wire is not exposed so this type of terminal is really great for marine use because we keep moisture completely out of this and we’ll look at how we do a heat shrink end here in a minute. A couple of other wire stripping devices that are out there that are pretty handy, this one here, what it’s going to do is it’s actually going to hold the wire and then strip the insulation off on the other side, so in this particular case we’re going to begin 10 gauge wire, there’s the amount that I want to strip off, as I close that, it holds the wire and then as I squeeze this, pops it right off and does a pretty nice job of stripping the end of the wire. Again, we haven’t broken any of those strands of the wire, I like that one a little better. I’m going to introduce you to another one here. This one is kind of neat in that it automatically adjusts to the wire gauge that you’re stripping. In this part of the tool here is adjustable to determine how much of the insulation you strip off. So this one’s pretty neat in that you just put the wire in to the stop, the little jaws come down and then you pull on it, strips the insulation off the wire, again, not being detrimental to any of those fine strands of wire. Any one of those three work really well. What we’re gonna do next then is to crimp the terminal end onto the stripped portion of the wire. In this case, we’re using one of the open-barrel style terminals, slide the wire up into the barrel there, and then we’re gonna take this style crimper, and it’s color coded also, as per the terminals, so since this is a 10 gauge wire, we’re using a yellow terminal end and we’re going to use that with the jaws appropriately. What you want to do is get that set up in there before we crimp it so we know the wire’s all the way in there and then as we push down on that, we’re gonna crush that barrel. And that’s gonna get our wire crimped good and tight into that terminal end. You still have the challenge of getting moisture in there, but if this is out of the bilge or something, this is a totally appropriate crimp then for this gauge wire. Next we want to crimp a heat shrinkable style. The heat shrink does nothing for the strength of the connection, the electrical connection, it’s strictly to keep the moisture out. So here we have again another 10 gauge, so we’re gonna use the yellow and it’s going to be inserted up into the barrel portion of the terminal, and in this particular case, we’re going to use a different, heavier duty crimping arrangement, but notice that it’s coded exactly the same way. We’ve got yellow, blue, and red color coding. So this opens, we’re gonna insert the terminal in there, align it with the jaws and this one actually crimps until it releases to get the proper crimping pressure. And so now that barrel is crimped. We’ve maintained a moisture seal here. So a heat shrinkable terminal end, we bring the heat on here and kind of rotate it like you were roasting a marshmallow and as it gets warm here, you see the… It shrinks right up tight around the wire. And now we’ve got a really excellent, not only crimp connection, but a seal so that we can’t get any moisture into those strands of wire. So the most appropriate place for this type of connection would certainly be with a bilge pump or anyplace where we’re gonna see moisture. I like using this everywhere on the boat, to tell you the truth, because then if there is moisture somewhere, we’ve got a well-sealed connection and we’re not worrying about that. I want to introduce you a little bit to what some of you may be familiar with which are called wire nuts. You see these a lot in home use, home wiring, and they’re appropriate for that. Remember when we talked about single strand type one wire, this is what they’re designed for and they’re appropriate for that. However in the marine environment, wire nuts have no use at all, the American Boat and Yacht Council and the U.S. Coast Guard actually prohibit the use of wire nuts, and that’s a function of them not being able to deal with the vibration you might find onboard a vessel, so you’ll see people jam a couple wires in there, tighten the wire nuts up onto that, and have a vibration problem. So let’s look at actually connecting the wires themselves to the terminal block or bus. When we have a group of wires all tied in common like we do here, this is the negative side, that’s called a bus, and I’m going to show you first I guess a connection that is inappropriate. So we’ve made a really nice connection up here, crimped it well, but we’ve chosen the wrong eye size on the terminal head, and you can see if we hook this up, while it might come tight, you’ve got a really lousy connection there. And of course this can flop all around on the terminal, so not only do we need to determine the right gauge wire for the application, we need to determine the right color coding for the crimp and we also need to determine the appropriate eye size in the end of the terminal. So in that particular case, that would be too large of a terminal even though the rest of it is appropriate. Here’s one where we’ve chosen the correct size eye. And that’s a much snugger fit, and we tighten that down and now we’ve got an excellent connection in that particular case. I want to demonstrate also a wire terminal end that’s inappropriate and I think most of you have seen this. This is the horseshoe arrangement, again, fairly typical of an automotive installation and it really is inappropriate for marine use also. And the reason gets back to this vibration issue again. Simple to connect, which makes it kind of handy to have, just slides underneath the screw and then can be tightened up, and actually, as long as the connection stays tight, that would be fine. The challenge is that if this screw vibrates a little bit loose, what you’ll find is this can come off really quite easily, and so again, this is an inappropriate terminal end for marine use, what we want to do in marine use is always use an eye type terminal so that if the connection does get loose at all, we don’t lose that connection.

– [Narrator] Next stop down the road in our series, Don gets us into the DC panel itself, and starts to bring it all together. We’ll see you then.



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