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Practical Wiring - Club Level: Wire Preparation

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Wire Preparation


00:00 - In this section of the course we will be demonstrating the practical wiring harness construction skills which are required to successfully undertake the HPA eight step harness construction process which we detail in the course worked examples.
00:14 The first practical skill we will look at is the preparation of our wires.
00:17 Sorting them and cutting them all to length.
00:19 This step does sound like it would be quite straightforward but it does still need to be approached with care to avoid mistakes that can cost lengths of wire.
00:27 Preparing our wires now also allows us to confirm that we have all of the required materials on hand.
00:33 From our prepared documentation we can determine how long every wire in our harness needs to be and where it needs to run.
00:40 Now when we're determining these lengths and cutting the wire, I tend to add around 100 millimetres to what our documentation actually shows as this does allow us to account for any length lost due to how the wire is going to run through the harness and where it branches out.
00:54 It is much much easier to trim a little bit of extra length from the wire when we're doing the final fit and finish than it is to be five millimetres too short.
01:03 So to show this process we're going to look at the four injector signal wires that form part of our wiring harness, so these are the low side switched wires that head from the injectors back to the ECU.
01:14 Now if we have a look at our documentation here, we've got our injector wires here and our ECU wires back here so it's a simple case of adding up the lengths in between to find the overall length that that wire needs to be.
01:27 So looking at our rear secondary injector wire here, from this branch point we've got 330 millimetres, we've got 170 millimetres here, we've got 350 here where it passes through the bulkhead.
01:40 And then back to our ECU is a further 250 millimetres.
01:45 So that wire needs to be 1.1 metres long.
01:49 So that is for our rear secondary injector wire.
01:52 We can see that our other injector wires are actually going to be different lengths as they are all a different length from this branch point here.
02:00 So now that we know the overall length of that rear secondary injector wire, we can take our spool of wire and our temporarily set up measuring tape here which is just blue tacked onto our desk, that's a really good way of doing it to keep it in position but also make sure you can remove it later.
02:17 And we will measure out 1.1 metres.
02:23 And I did mention that we want to add around about 10% or 100 millimetres to these measurements to make sure to account for any wastage that's going to happen as this wire runs through the wiring harness so I'm actually gonna measure out 1.2 metres there.
02:41 And we can trim that wire off.
02:44 So this is going to be our rear secondary injector wire.
02:46 Just going to coil this up tidily and pop it to one side and then I'm going to repeat that process for those other four injector wires in the wiring harness.
03:09 So we've got our injector signal wires all trimmed to length there, our four bundles, for our four injectors.
03:15 What I would now do is either store these together with cable tie or possibly in a clear plastic bag and note them as being those injector wires because we've trimmed those to length and they're out of the way.
03:25 We can move onto the rest of the wires in our wiring harness now.