Amp Gauge Wire Diameter (AWG)

[SlantedMark4]

'm sorry for opening a new thread AGAIN but I wanna be sure before I screw up. I need to replace one of the cable terminals (I guess) on one of the ammeter cables (I've had the infamous ammeter problem thingies, 65amp wiring/trouble shooting), so the insulator melted a bit. To replace the terminal, I need to know the AWG / mm2 stuff but I have absolutely no idea about wiring / electrical stuff.

I've just found out that the standard cable must be AWG 3 I guess...? So the outer cable diameter is 0.228in / 5.8mm which it actually is on my car. Now, does it matter what type of terminal I use or do I need a special AWG 3 terminal stuff or is it enough to get a terminal where the cable fits in? Do I need a special type of insulator? I mean the standart insulator is very thicc...
The easiest way is to mount it as it is but it won't work properly I guess..?
I just don't want to risk another electrical fire due to bad repairs...

 

[Mattax]

Quick overview:
We can't easily tell the wire gage by the insulation (Unless we happen to have samples of the same wire).
I've been known to successfully guess the gage when posted in photos but I wouldn't place bets on being able to do so consistantly.
Wire gage is based on the conductor diameter. Automotive wire in American cars used SAE wire gage standards. Its close but not the same as the American Wire Gage standard.

Insulation comes in different thicknesses and materials.
Near the engine an oil and heat resistant insulation will hold better.

If you show some photos of the wires where we can see the standard harness circuits next to the heavy duty circuits we can probably make a reasonable guess as to whether the HD conductors were 10 gage or 8 gage.
We kindof working toward that before...

PS. You will need special crimpers to do the larger wire size "F" crimp terminals.

 

[Mattax]

Examples

The red jacketed tin-coated thin stranded wire is 10 gage marine wire. Next to it is 10 gage automotive wire.
The white and blue wires are both 14 gage automotive wire.
The brown is 16 gage general purpose automitive wire. It shows some oxidation and should be examined further to see if the oxidation continues up under the insulation.

 

[Mattax]

If you show some photos of the wires where we can see the standard harness circuits next to the heavy duty circuits we can probably make a reasonable guess as to whether the HD conductors were 10 gage or 8 gage.
We kindof working toward that before...

Normally we can use the wire gages provided in the diagrams.
But with the optional wiring on your car, its not quite what is shown in the diagram. Once we figure that out, then whether the wire you want to work on is 12, 10 or 8 gage should be pretty clear.

Look at the wires going to the ammeter in the diagram

Here's how the codes work.
First letter and number is the circuit. Next letter is the wire segment. Followed by wire size and insulation color.

Lets pick one and decode it.
At the alternator, the optional output wire is R6E 8 BR
R6 = Alternator output
E = First segment (optional wiring only)
8 = SAE wire gage
BR = Brown

 

[SlantedMark4]

Normally we can use the wire gages provided in the diagrams.
But with the optional wiring on your car, its not quite what is shown in the diagram. Once we figure that out, then whether the wire you want to work on is 12, 10 or 8 gage should be pretty clear.

Look at the wires going to the ammeter in the diagram
View attachment 1716033738

Here's how the codes work.
First letter and number is the circuit. Next letter is the wire segment. Followed by wire size and insulation color.

Lets pick one and decode it.
At the alternator, the optional output wire is R6E 8 BR
R6 = Alternator output
E = First segment (optional wiring only)
8 = SAE wire gage
BR = Brown

That last part really helped me. Thank you mate!
The wire in question must be AIG 10R, the wire that comes from the grommet onto the ammeter.
So it must be AI circuit, G segment, 10 sae wire, red, I guess

 

[Mattax]

That last part really helped me. Thank you mate!
The wire in question must be AIG 10R, the wire that comes from the grommet onto the ammeter.
So it must be AI circuit, G segment, 10 sae wire, red, I guess

Yes. the battery feed is A1.
According to the diagram the segment through the grommet to the ammeter is a 10 gage wire.

You can compare it to the other wires nearby.
The other wires through the grommet should be the same diameter. Where did each connect is the question?
The one connecting on the ammeter is probably also gage, but these wires in the diagram doesn't match what's on the car.

So

Compare with the standard wiring that is there.
Look at R6 B where it goes into the multiconnector. That's 12 gage
Whether R6C or C13 was on the ammeter stud may not matter as both of them are supposed to be 12 gage as well.
etc.

If, upon removing the insulation, the wire strands and crimp looks, or just needs some cleaning, then cleaning and reinsulating is a good option.

If the wire strands or crimp is poor, then see if the spare harness section you obtained has the same ring terminal and wire.
You may have to splice in a section but with 10 gage wire I think you will be able to create a better wire splice than wire to ring terminal connection.

 

[Mattax]

This is a 1980s jeep but provides an example of oxidized battery feed in the engine bay.
There was a small break in the wire insulation, and some greenish copper oxide could be seen.
Removed the molded insulation and slit the wire insulation open.

That's not good. Current carrying capicity of that wire is reduced.

The fibre 'pen' and Deoxit can be used for cleaning.

Can it be done repaired. Yes but it is difficult. I did it on the bench.
This one is Chrysler.

Crimped and soldered. Crimping needs an open barrel crimper that can handle heavy terminals for 10 gage wire.

Like I posted before, wire splicing is a bit easier.

 

[SlantedMark4]

Yes. the battery feed is A1.
According to the diagram the segment through the grommet to the ammeter is a 10 gage wire.

You can compare it to the other wires nearby.
The other wires through the grommet should be the same diameter. Where did each connect is the question?
The one connecting on the ammeter is probably also gage, but these wires in the diagram doesn't match what's on the car.

So

Compare with the standard wiring that is there.
Look at R6 B where it goes into the multiconnector. That's 12 gage
Whether R6C or C13 was on the ammeter stud may not matter as both of them are supposed to be 12 gage as well.
etc.

If, upon removing the insulation, the wire strands and crimp looks, or just needs some cleaning, then cleaning and reinsulating is a good option.

If the wire strands or crimp is poor, then see if the spare harness section you obtained has the same ring terminal and wire.
You may have to splice in a section but with 10 gage wire I think you will be able to create a better wire splice than wire to ring terminal connection.

I've cut off the spare cable and just found out the big insulator rubber thing is different from a standard to a 60 amp configuration