the rule of thumb is 2 wire sizes smaller than the wire you are protecting. be
sure to use fuseable links and not just a smaller wire even though that will
work, it doesn't have the stinky insulation that burns easily so finding the
link will be easy. i suggest putting the fuseable link by the starter like
modern GM vehicles.thats the blue (?) wire on the starter [going by memory on
the wire color]14 gauge is way too small for the alternator wire. The minimum
size is 10 gauge like the factory uses. if you use a 2 wire alternator, be sure
the exciter wire is hooked up in series with a idiot lamp or a 10 ohm resistor.
ohms law is volts times amps = watts. watts divided by volts = amps, watts
divided by amps = volts, so doubling the volts cuts the amps in half. a 6 volt
harness with 12 volts going through it is like an extra duty wiring harness,
because at 12 volts as opposed to 6 volts runs at ½ the amps.
"J.O. Williams" wrote:
> >
> <Snipped>
>
> > I'd suggest adding a 14 gauge fusible link in the wire that goes to the +
> > battery terminal, which feeds power to the whole electrical system.
>
> Do you have a rule-of-thumb for the fusible link amperage? Having just
> fried a 20 year old 6V wiring harness, a fusible link will be the first
> item I install. From what I can gather from the GMC '51 wiring diagram
> and with everything turned on, the total load should be about 55 amps
> at 6V (or 27.5 amps at 12V). True or false or what should it be?
>
> You mention a 14 gage fusible link, I assume that 14 gauge is for 6V?
> If 14 gauge is for 12V, then what gauge should it be for 6V?
>
> It is probably for the better that the harness burned up... All the
> red insulated wires in the harness were cracking and exposing bare wire.
> I was wrapping the red wires in black electrical tape to hold the
> insulation on. None of the other colored wires were having this
> problem. The harness had been purchased from JC Whitney in 1980(?)
> and had been manufactured in Brazil. When you bridge the plus side
> of the amps gauge to the ground (the instrument light bulb holder)
> a lot of heat, light, and smoke is produced. Now none of the red
> wires have insulation.
>
> >
> >
>
> --
> J.O. Williams
> '51 GMC
>
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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