Burning wire

Guys i have a small block chevy and the 12 gauge wire that goes from my alternator to my positive cable is unusually hot and it burned up after i crunk the car up and had it running. I cut it towards the end of the wire like an inch after it starts and replaced the rest of the wire with some new 12 gauge wire and the new wire is getting really hot to but it hasn't burned yet but it is so hot when u touch it i can tell its going to eventually burn to. Now the positive cable isn't hot, its just the small wire that comes out of it and goes to the alternator. Do i just need to replace the positive cable? I never had this problem until i had someone to take this engine out of my other car and put it in another car.

Check your grounds. Make sure the ground straps from the engine to the chassis are in place. Sounds like amperage is travelling through that 12 gauge wire instead of through the battery cable.

Pat

Keep throwing 12 gauge wire at it.....you'll get lot's of practice doing it over and over again.

Quote:

---

Originally Posted by Stu Cool

Check your grounds. Make sure the ground straps from the engine to the chassis are in place. Sounds like amperage is travelling through that 12 gauge wire instead of through the battery cable.

Pat

---

yup look at the lack of a good ground you can not have to many grounds

Quote:

---

Originally Posted by nitrowarrior

Keep throwing 12 gauge wire at it.....you'll get lot's of practice doing it over and over again.

---

Doh! How'd I miss that? Nitrowarrior's got it. That should be a 8-10 Gauge wire. I would still check the grounds.

Pat

yep that is abit on the thin side some of the wire you get at the auto stores is over rated use 8 gauge if you can find it

About two weeks ago I rewired a Truck at work That same wire was Cooked from the alternator to the starter . Well I installed a New wire same size as stock ( Not A Very Large Wire ) Hooked up the battery . The old Burn Test started all over again . Found alternator was bad . Installed new alternator Now it's making Money .

That wire has to carry the rated output of the alternator---unless you are using it as a fusable link--today with all these high amp alternators and godzilla batteries, fiberglass bodies, rear mounter batteries, powdercoated everything, very few cars are wired adequetly

In most of the cars we work on with electric fans we run a dedicated wire from the alternator to the fan relay so it bypasses most of the system to/from the battery

Anyway put a number 6 to that main cable and also a number 6 from the alternator base to the battery post negative and most of your problems will go away---

You got it Jerry!!! Everyone wants to add the mega output alternators and a gazillion electrically powered gizmos---then expect the stock wiring to be up to the task....

BTW, in touring the junkyard the other day, noticed a bunch of fire damaged cars....... just coincidence, I'm sure.......:rolleyes: :rolleyes: :rolleyes:

Its a 100amp alter. and the battery is a red top optima, which is only about two years old and I have an electric fan hooked up to the negative cable, its a 75 impala. But the battery isn't holding a charge overnight and i don't know whether we jumped it off to many times and killed the battery, or is it grouded wrong and thats why it won't hold a charge. Had no problems until he took this engine out and swapped it in this car. only thing different is i put an elec. fan in this car.

the alt could be bad there a diode in the alt if it is bad it will drain the bat and it could have a short somewere i do not know how you have your fan wired

Could be wrong, but sounds to me that you fried the alternator and its output is going straight to ground. Should also be the reason the battery won't stay charged.

Are you running a relay on the fan, or did you wire it direct????

Need much bigger wire
Need a fusible link
Need to check bleed on regulator
Need fire extinguisher

http://www.alphawire.com/PAGES/383.CFM

Quote:

---

Originally Posted by Dave Severson

Are you running a relay on the fan, or did you wire it direct????

---

Ran it straight to the negative cable

Well knowing that the engine has just been changed,have all the engine grounds been re-installed? Another thing I have seen two or three times,are you dead certain there are no wires pinched in between the block and the bell housing? I can't see a problem with grounding the fan, where are you picking up its power? Have you charged and load tested that battery? Just some thoughts,Hank

Quote:

---

Originally Posted by Geronimo

Need much bigger wire
Need a fusible link
Need to check bleed on regulator
Need fire extinguisher

Wire, Cable and Tubing Solutions from Alpha Wire Company

---

all very good suggestions... as food for thought, I use a maxi-bus fuse instead of a fusible link... I personally think they are safer, and I keep a spare in the car... fusible link goes... you're down for the count... fuse blows, replace and keep going! (assuming it was just excessive load that caused it to blow)

I use a holder with 8 awg wire... (70 amp rating)

http://www.vteworld.com/content/elec...axi_holder.gif

http://www.vteworld.com/content/elec.../maxi/maxi.gif

There is some great information and advice on using modern electronics in older cars here:

MadElectrical.com - Mad Enterprises

Whether you buy his kits or not, the tech articles are worth reading. I have applied several of them to my rig.

Pat

If you have the relay hooked to the negative terminal you have the polarity backwards---is the batt hooked up reverse?? if not you are probably creating a direct high amp short anytime the relay is energised!!!!

If you have a voltage regulator you have probably damaged it , if your alt has internal, you probaly damaged it---or both!!!

Quote:

---

Originally Posted by jerry clayton

If you have the relay hooked to the negative terminal you have the polarity backwards---is the batt hooked up reverse?? if not you are probably creating a direct high amp short anytime the relay is energised!!!!

If you have a voltage regulator you have probably damaged it , if your alt has internal, you probaly damaged it---or both!!!

---

Don't have relay just grounded the fan to the cable, no voltage regulator and the battery isn't reversed

12 ga wire is good for 35 amps up to 4 ft run....it sounds like your wire should be bigger. A 10 ga wire is good for 50 amps, an 8 ga is good for 65 amps, and a 6 ga good for 105 amps, all at 4 ft or less.

My guess is that the harness is for an old, small alternator. We typically run high strand welding cable from the battery to a high amp (200 amp) alternator.

I thought that typical GM cars had a 10 ga alt wire....not 12.

Mike in Tucson

Quote:

---

Originally Posted by robot

12 ga wire is good for 35 amps up to 4 ft run....it sounds like your wire should be bigger. A 10 ga wire is good for 50 amps, an 8 ga is good for 65 amps, and a 6 ga good for 105 amps, all at 4 ft or less.

My guess is that the harness is for an old, small alternator. We typically run high strand welding cable from the battery to a high amp (200 amp) alternator.

I thought that typical GM cars had a 10 ga alt wire....not 12.

Mike in Tucson

---

So should I try a 6 or 10 gauge wire?

If you have the 6 ga, it wouldnt hurt. However, the size wire choice is influenced by the ring terminals that you can find for the alternator post. For instance, if the post is a small 1/4 thread, it may be tough to find a ring terminal that fits a big wire to little post. So, first figure out what size the alternator post is and then look for the correct sized ring lug...and buy that sized ring for the largest wire you can. For instance, if the alt post is 1/4", you will have some choices for wire that will probably be 10 ga and smaller. Usually 6 ga ring lugs take a 3/8 bolt.

Depending upon the make of car, there should be a wire from the alternator output to the battery + and another wire from the battery + to either the starter (GM) or solenoid (Ford).

I used welding cable on our 200+ amp alternator and it doesnt get hot unless we are running a really high amp draw (like a Warn winch).

Mike in Tucson