3G wiring...

[Boydster]

I have a 3G alternator installed with a wiring kit from PA as sold by American Muscle.

The instructions with the wiring kit have me installing ring terminals on the 2 black/orange power wires and installing them on the alternator power terminal in addition to the new 4 gauge cable.

I did it this way and it is working fine.

I read a lot on here and have read several times to leave these 2 wires disconnected from the 3G alternator.

What's the best way and why?

 

[ID89GT]

Only thing I can see is it provides more cable to charge with. If you already have a 4 gauge then that is plenty, so I don't see the point of hooking the other two up as well

 

[Boydster]

Only thing I can see is it provides more cable to charge with...

That's what I figured, and why I went ahead and installed all 3. Looks better than having an open plug hanging off, too.

True, they may not be needed, just wondering if anyone has a really good reason for NOT installing them.

 

[Beasty306GT]

i installed mine with just the 4g wire

 

[4rdnut]

The reason people don't hook up the orange and black wires is if the fuse on the 4 gauge cable blows, the orange and black wires are too small to carry the extra amperage of the 3g alt possibly causing a fire. I would like to see a test done too see if thats true.

 

[hsean]

just curious i have a brand new alternator that came with my car and my motor is stock what are the benefits/reason to upgrade to 3g?

 

[4rdnut]

The stock alt is borderline when it comes to keeping the battery charged and when adding an electric fan a 3g is mandatory. The stock alt had problems with the wire plug heating up and melting causing the wires to short out.

 

[jrichker]

Here is the reasoning behind using only a single 4 gauge fused power feed to the alternator. If you use the two 10 gauge black/orange wires in addition to the 4 gauge wire, you have two fused power feed paths. The total current capacity of the wiring is the sum of the fused paths. The 4 gauge path is fused for 125 amps, and the two 10 gages wires are fused for 60 amps. That is a total of 185 amps, which exceeds the capacity of the alternator. Overload can occur without the fuses blowing, damaging the alternator.

The worst case scenario is that the alternator develops an internal short to ground resulting in a catastrophic failure. The initial short circuit surge current is limited by the resistance of the wiring. The current in a parallel circuit divides up according to the resistance of the branches. If the 4 gauge fuse opens up first, the two 10 gauge black/orange wires will be carrying the short circuit surge current. Depending on the time lag of the fuse links, they may open up before a fire starts or they may not.

If you have any more questions, I''ll go blow all the dust off my first semester electronic theory book and give you the names of the laws governing current flow in parallel circuits...

 

[Boydster]

OK, I'm with ya and understand the theory.

I asked why and you explained it well. Thanks.

I suppose the same thing could happen if the 4ga fuse opens up for a non-short situation... such as age or vibration. Suddenly the twin 10ga wires are trying to carry the load, and as you said, the fuse links may or may not open in time to prevent a fire. With only the 4ga, you just have a dead alternator.

Thanks again for posting up.

 

[Boydster]

The reason people don't hook up the orange and black wires is if the fuse on the 4 gauge cable blows, the orange and black wires are too small to carry the extra amperage of the 3g alt possibly causing a fire. I would like to see a test done too see if thats true.

Thanks, 4rdnut. 2 votes for the same reasons... looks like I'll be capping off the twin 10's.