Building the Harness Part 2
By Geoff Kremer
So you got hundreds of wires!
Well I suppose its all well and good talking about electrics and current etc but! How are you going to actually build a wiring system that is going to do what you
Once youve drawn down the way the harness is to be run you can start laying the wiring in place. Remember, when youve got all the wires in place and clipped it together with tywraps or loops of adhesive tape, this is called tacking, you will need to remove the harness intact to add any splices and to finish wrap it. Bear in mind that when the wiring is finish wrapped it will be very stiff so you need to be careful to make sure you can re install the wiring easily. Youll have to remove any tywraps as you approach them.
Start at the dash board end or where the fuses are located and lay the cables following your diagram. When you come across a splice point, lay the cable in and tape it to the wire it is to be connected to. Add at least an extra 6 inches to each wire at its connection point, even if you think youve allowed enough. Tywrap or tape the wires every 6 inches or so and where a cable is to leave the main bundle put a tack each side of the exit point. Where the harness is to follow a bend put tacks every couple of inches or so, so the wires keep their shape. Where the wires run inside a conduit, rails or tubes ect, tack the harness as soon as its removed.
With the harness removed add any spurs and splices now.
Actually taping the harness can be tricky so here are some hints.
Grip one end of the run to be taped in a vise or tie it to a table leg or something.
Dont try and wrap the harness using tape on the roll, unreel about 2 meters worth and use that, make sure you keep it nice and clean otherwise it wont cling properly. Start by trapping the end between the wires. When you come to the end of a length of tape, trap it between the wires and start the next piece by overlapping the previous few turns.
When youve come to the end of a run twist the tape by rolling it between two fingers then you can tie it off like string! Or wrap a few turns of adhesive tape and for a more permanent slip some shrink tubing over and heat.
Keep a constant tension on the harness and tape. Use a thumb or finger to lock each turn in place.
By altering the angle of the tape as you apply it you can vary the stiffness of the harness and mostly you should aim for an overlap of 50% as you wind the tape on.