MATT: The way I’ve always thought of how electronics work is like how water flows.
Water flows from point A to point B, the same as sort of voltage does.
My name is Matt.
I build motorsport wiring harnesses and I’m from South Wales.
We’re building this motorsport wiring harness for a Lotus Exige.
The application for this car is going to be an endurance race car so it’s obviously got to put
up with a really harsh environment to withstand that amount of torture for a long period of time.
The wiring harness connects all the elements together to make the engine work.
When we get the car we’ll start by doing all the harness routing.
We use nylon rope which gives us a nice visual representation
of where the harness is going to run, routing the harness around the engine,
making sure that it sits in the right place and it doesn’t interfere with anything.
We’ll use the mock-up harness to then create a digital version
giving us all the lengths and all the dimensions and stuff that we need.
The next step is prepping to build the harness.
We’ll cut all the wires to length.
We’ll start laying everything out on the bench so
that we’ve got everything to hand when we start building the harness.
After we’ve done all the prep work we’ve got to pick a starting point of the harness.
Once we’ve fully terminated the starting point we’ll then orientate all the wires
and service loop the ends of them so that they’ve got some strain relief and they can
be serviced or if something needs to be changed there’s extra wire there.
If you’re going to bundle a load of wires together you’ll end up with a short wire
on the inside of the curve and a long wire on the outside of the curve.
Concentric twisting is a way to have all the wires in the harness
the same length and give the harness flexibility.
I enjoy the concentric twisting the most.
It’s the most pleasing part of it and it gives you the most satisfaction.
The next step would be we organise all the wires and
lay out the harness according to our layout diagram.
If we run out of wires and we need to fill the gap in the last layer we’ll use filler wire
to fill the gaps and create that nice smooth circular looking harness.
The tape we use is called Kapton tape.
It’s basically a heat barrier so we wrap it around the transitions so that it protects the
wires from the intense heat of shrinking down all the parts in the moulded boots.
Once we’ve got a fully formed harness we’ll then add all of the labels on.
We’ll add all of the moulded boots on for the transitions.
We’ll then trim all the wires back and add all of the final connectors and end terminations.
We’ll add the epoxy resin to seal up all the joints and seal up any gaps
so that moisture can’t get inside the harness.
The moulded boots take quite a bit more heat so we can shrink them in the range 350 to 500 degrees.
We use a [?] box to enable us to add on a more reliable connector.
We’ll place the harness on to the car, route it around where it’s got to go.
We’ll then clip all the connectors into place,
bolt the distribution box down and then that’s our job done.