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Wiring Fundamentals: Labelling

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00:00 - Labelling our wiring harness might initially not seem like a critical step in the construction process but it's well worth considering for the level of professionalism and ease of installation it adds to the finished product.
00:11 Particularly in situations where electronic devices close to one another in the engine bay have common connectors, labelling our harness terminations will help avoid the wrong connections being made and the possible damage that might result.
00:22 To create the labels we use on our harness, we use a thermal printer capable of printing onto heat shrink tubing.
00:27 Only a few years ago these were still very expensive devices, out of the reach of someone constructing a single wiring harness or even small workshops.
00:35 The last couple of years have seen the price of them reduce dramatically to the point where a good machine can now be purchased for only a couple of hundred dollars.
00:42 An important consideration though is the price of consumables.
00:45 The thermal printer we have here is a 3M PL300 which is equivalent to the Dymo Rhino 6000.
00:51 And the thermal transfer heat shrink cartridges it takes are very expensive.
00:55 There are thermal printers on the market that take a separate replaceable thermal transfer ink roll and heat shrink roll.
01:01 These are more expensive up front but the price of consumables is much less.
01:05 So if you're in a situation where you'll be building many harnesses, they would be worth looking into.
01:10 To label our harness we refer back to our design documentation as our connector names will be listed here and it's important that they match.
01:16 Anyone working on the car in future using our documentation as a guide, will find it much easier if the text on the labels is an exact match to our documentation.
01:26 We'll go through an example of labelling now by using our sample injector branch section from our RX-7 race car sample documentation.
01:33 So the first stage of our labelling process is to determine the size of heat shrink we're going to need.
01:38 The heat shrink used by this printer has a shrink ratio of 3:1 so we can actually just do this by eye as it's not completely critical.
01:44 All we need to ensure is that we can get it over the branch in its unrecovered form and that it's nice and tight once it's been recovered.
01:50 So we've got half inch heat shrink tubing in here which will recover down to approximately four millimetres which is gonna be a nice tight fit on these branches.
01:59 So with that sorted we can start to print our labels and for that we need our documentation as it's got the text we're going to put on our labels here.
02:11 So with our printer on, the first thing we wanna have a look at is just the settings that we've got it on here, so this is the fault size and any attributes we've applied.
02:19 Now these are not critical, they're totally personal preference, however you want to make sure they're the same for the entire wiring harness as it'll just add to the uniform look and sort of professional appearance.
02:30 So we'll go ahead and enter this text now.
02:39 Excellent so I've entered the text there in one long string and this means it will print it all out on one continuous piece of heat shrink.
02:45 This is actually just to conserve the amount of heat shrink we're going to use.
02:48 We'll trim them all to length once they've been printed out.
02:51 So we'll hit the button.
02:58 So with those labels printed, we can cut off the section of heat shrink tape.
03:03 And we've got our text there, so we'll just cut these into the individual sections that we need.
03:14 So with our individual labels cut there, the next step is we're going to cut a section of clear heat shrink that's approximately four millimetres longer than each one of these labels.
03:23 When we recover these onto the expandable braid, we then recover a section of clear heat shrink over the top of them which just provides added protection and stops the text from rubbing off over time.
03:32 The type of clear heat shrink we have here is called Raychem RT375.
03:37 There are a few different types of clear heat shrink on the market.
03:41 I haven't found a massive difference between the different brands.
03:44 However I have found this one easy to source and reasonably well priced so I've stuck with it.
03:55 So with all our labels prepared, we can go ahead and install them onto our branches.
03:59 Now in this instance with our sample harness here, it's not going to matter which label we put onto which branch, but when an actual harness build, that would obviously be critically important so you really need to double check that you're installing the right label onto the right harness branch.
04:13 The thermal printer prints on the heat shrink in a flat form and we just use a wee tool to open that out a little bit.
04:22 And then we can slide that onto our branch.
04:27 And you want to pay attention to the direction that the text is reading.
04:30 Once again it's personal preference for which way around you would like to have it, but you want to keep it uniform across your entire wiring harness.
04:38 This heat shrink does have a very low full recovery temperature.
04:41 But that being said, I've kept our heat gun set at our 200 degrees celsius as I know that it'll recover it very quickly and it's not going to be in danger of melting our expandable braid.
04:50 So with that all in place, I'll go ahead and recover this label onto this branch section now.
04:58 So we can see that label has recovered onto our expandable braid nice and tight so it's gonna remain in place.
05:03 And with that done, we can install our piece of clear heat shrink tubing.
05:08 And we want to make sure that this is centrally located over the label.
05:12 Once again just adds a really nice professional detailed look to the harness.
05:19 So with that in place, I'll go ahead and recover that now.
05:25 So that clear heat shrink has recovered nice and tightly onto our label.
05:28 The text is completely legible and it'll be well protected for many years to come.
05:33 So the next step is to do the other three branches.
05:36 You want to be certain that when you do those, you get all the labels the same distance from the end of the branch section.
05:43 Just about keeping it uniform again, that nice professional appearance that we're going for.
06:18 So with that operation completed, you can see we've got all our labels in place and nicely protected.
06:22 We've got that really professional look that we're going for.
06:25 All the labels are the same distance from the end of the branches and the text is all facing the same direction.
06:31 So by reading those, anybody installing this loom, there should be no excuses for any wrong injector connections being made.

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