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Practical Wiring - Club Level: Materials Selection

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Materials Selection


00:00 - Selecting the materials we're going to use to construct our wiring harness can be a lengthy and confusing process.
00:06 There is a lot of different information out there around what is best to use, and the reality is that there is usually more than one option.
00:13 I have a couple of lines in the sand around material selection for a club level race car or a modified street car which I use to streamline the process.
00:21 When choosing the wire used to construct a harness for a modified street car or club level track car, I use TXL insulated wire.
00:29 As the space saving and weight benefits of tefzel are not worth the extra cost at this level.
00:34 That being said, TXL wire is not easily available in all parts of the world, and if tefzel insulated wire is more easily available in your location, and you can purchase it in small quantities it may be a better choice.
00:46 When it comes to deciding what colour wires you are going to use, I have a scheme which I've developed and stuck to.
00:52 All power supply wires are red.
00:54 All power ground wires are black.
00:56 Sensor supply wires are orange and sensor ground wires are green.
01:01 All other wires such as sensor signal and actuator command wires are white.
01:05 CAN network wiring is a twisted pair of white and green wires with CAN high being white and CAN low being green.
01:14 Having all the sensor and actuator wiring being white may initially sound like it would be a little confusing but in reality it does take very little time with a multimeter to find the wire you are after when you're terminating and pinning your ECU connector.
01:27 If you're then troubleshooting a signal out at the other end of the wiring harness a sensor or actuator, you can quickly determine which wire is the sensor signal, sensor supply, or sensor ground.
01:38 For the protective sheathing we will use to cover our wiring harness, there will be one of two options which we will use, or possibly both in some situations.
01:47 These options are expandable braid or DR25 heat shrink tubing.
01:51 The deciding factor between these is going to be cost with expandable braid typically being less expensive than DR25.
01:58 Often we will sheath the portion of the harness which enters the engine bay in DR25 due to the extra protection that it provides, but switch to expandable braid for the interior section as it can be easier to work with around large ECU connectors.
02:12 To support and seal our harness transition points, that it the points where the harness branches out from our main trunk to the individual sections which head off to sensors and actuators, we will use a section of raychem SCL dual wall rigid shrink tubing.
02:27 It gives excellent strain relief.
02:29 We will also cable tie the exit of these branch points as a last piece of added strain relief.
02:35 I pre cut my sections of ECL used for this purpose so any pieces used for transition support that are the same size are also the same length.
02:43 This level of detail will ensure your harness has a professional finished appearance.
02:49 While it's not strictly necessary, labelling our harness can help prevent mistaken connections being made where two actuators or sensors are mounted close to one another and they share a common connector.
02:59 It also adds that professional appearance to the harness which is always nice.
03:03 To do this we use a label printer capable of printing onto shrinkable tubing and then a piece of clear heat shrink tubing over the top of that label to protect it.
03:13 The printer we use here is a Brother PL300 which takes cartridges in the back containing different sizes of shrink tube.
03:19 The clear label we shrink over top is cut so it is two millimetres longer than the underlying label, giving us one millimetre of overlap on either end.
03:28 Once again, this uniformity in the construction of our harness will help give it that professional appearance that we really are aiming for.
03:35 The connectors we use to build out harness will largely be defined for us by the component that we are making a connection to.
03:41 If this is an aftermarket component such as an ECU or a higher flowing injector, the connector itself will be supplied with the component or a part number to make sure ordering the correct connector is as easy as possible.
03:53 As mentioned in the component inspection and physical mounting design skills section, identifying the connector used on OEM electronic components can be much more difficult, requiring independent internet research.