Wire Gauge Question(s)

[Jon Davis]

All,

I am building a new harness for an RF92. I have chucked the old harness away as it has had some form of high resistance 'thermal event' in the past so learning from that is not a sensible option.

I have concluded that in the majority of cases the wire gauge is more driven by the robustness of the harness than the amp draw of the electrical lump at the end of the wire. BUT this is not the case for the Starter Solenoid and Coil as far as I can tell (Oh and the main battery + and - cables of course but that goes without saying.).

So . . . what wire size are YOU using for your Starter Solenoid and Coil. It has been suggested that the current draw from the Coil could be 4.5 amps and to the Starter Solenoid 20 amps . . . but I do not have this nailed down (I can do the electrical math if I am confident in the current draw figure).

Advice gratefully received.

[martyn_mcg]

i used 2mm wire for the coil and started solenoid, which is good for 25 amps and has worked fine for me, i used 1mm wire for gauges and all the other bits and bobs.
i did try to use a good quality thin wall 'auto cable' and found that using the glue lined heat shrink on the terminals gives a real good watertight joint

i hope this is some use to you!

Regards, Martyn

[Yibs]

Hi John

You could measure the resistance of the solenoid coil then use Ohms law to calculate the current draw of the circuit then build it with wire rated a couple of amps higher for a little extra protection and enjoy "thermal event" free motoring. This would also work for the ignition circuit or any other curcuits you might want to make.

Yibs.

[Jon Davis]

MARTYN_MCG . . . when you say 2mm and 1mm what do you mean? OD over insulation . . . cross sectional area of wire (14AWG and 17AWG)?

YIBS . . . happy to do the math but don't have the equipment to make the measurements . . . and if someone else has the quick answer from their build book then that saves me a load of digging around.

[martyn_mcg]

i think its the core diameter of the wire inside the insulation, just look for marine wire, or auto wire on e-bay and you will get many companys listing the wire as 1mm, 2mm, etc.. and they will state the max amps and you can pretty much pick any colour you like, the stuff i got hold of was very good quality, and the 2mm wire has had no problem at all on a high torque starter motor... http://stores.ebay.co.uk/kojaycatvehiclewiring

[Jon Davis]

MARTYN_MCG

Thanks for the pointer to the EBay seller . . . the details I was after are in the descriptions he uses. Bingo!