Copper Clad Aluminum ground cable

[Patrick H.]

For years I've heard Bill Clupper refer to the "Copper Clad Aluminum" ground cable that started to be used in 1972. I assumed he was correct, but yesterday when working on the orange 72 I found this:



I had removed the cable because the end that attaches to the frame had a "cut" in the casing and was starting to corrode:



For those that recall the Cincinnati Regional in 2005, my yellow 72 had a similar issue in the exact same spot, and it kept my car from starting when I attempted to leave the judging field. I think that the cable hangs down "just" enough to catch the occasional item, scrape the casing and allow corrosion. Just my hypothesis.

Patrick

[Edward J.]

Re: Copper Clad Aluminum ground cable

Partrick, see it all the time in my automotive business, here in the north east salted roads and high humitity, battery cables do corrode and once the casing is cracked or broken its only a matter of time.

[Patrick H.]

Re: Copper Clad Aluminum ground cable

Partrick, see it all the time in my automotive business, here in the north east salted roads and high humitity, battery cables do corrode and once the casing is cracked or broken its only a matter of time.

Yes, here in the upper midwest it's the same.

It's interesting that the issue was the same year car and the same spot. I suspect that the cable hanging down a bit was not a huge consideration when they were assembling these cars.

[Michael G.]

Re: Copper Clad Aluminum ground cable

Looking at your pic, I'd guess that the copper "cladding" on the terminal was scraped off after repeated assembly, (a very strong possibility). If this occurred, you have been grounding through an aluminum joint. Over time, the aluminum will form an oxide on its surface, an oxide that is not very conductive. The more oxide that forms on the grounding surface, the smaller the ground path. This can lead to to overheating of the wire. The melted plastic on your ground wire is probably result of such overheating. While putting on a new copper clad aluminum wire is probably OK for normal use, if the car is to be driven in corrosive atmospheres, it probably wouldn't hurt to switch to a copper wire.

[Jim T.]

Re: Copper Clad Aluminum ground cable

Patrick what is the length of your negative battery cable?

[Clem Z.]

Re: Copper Clad Aluminum ground cable

you can tell by the weight as the aluminum cables as they are feather weight. they also cause starting problems even if they don't short out because they get high resistance as they age

[Michael G.]

Re: Copper Clad Aluminum ground cable

I remember having to rewire the tail lamps on my boss's Impala (70 something, can't remember) when Chevrolet tried to use the aluminum wire throughout. Spent a long time looking for the fault before finally running a new line.

[Clem Z.]

Re: Copper Clad Aluminum ground cable

I remember having to rewire the tail lamps on my boss's Impala (70 something, can't remember) when Chevrolet tried to use the aluminum wire throughout. Spent a long time looking for the fault before finally running a new line.

a lot of houses burned down because of the aluminum wiring because it developed high resistance and over heated. my cuz was a electician and refused to use it

[Terry M.]

Re: Copper Clad Aluminum ground cable

a lot of houses burned down because of the aluminum wiring because it developed high resistance and over heated. my cuz was a electician and refused to use it

Aluminum wire inside homes turned out to be a problem because of the type of connections used, and that the need for special connections was not fully understood.

If your electricity comes to your house on overhead wires the chances are very good that those wires are aluminum. With the proper connections there is no problem connecting to your copper house wire. Utilities use a lot of overhead aluminum wire. It does take proper connections though.

None of that has much bearing on the copper-clad aluminum battery cables used in 1972 and later Corvettes, except I note the terminal appears to be attached much like the terminals on the copper wires.

[Clem Z.]

Re: Copper Clad Aluminum ground cable

Aluminum wire inside homes turned out to be a problem because of the type of connections used, and that the need for special connections was not fully understood.

If your electricity comes to your house on overhead wires the chances are very good that those wires are aluminum. With the proper connections there is no problem connecting to your copper house wire. Utilities use a lot of overhead aluminum wire. It does take proper connections though.

None of that has much bearing on the copper-clad aluminum battery cables used in 1972 and later Corvettes, except I note the terminal appears to be attached much like the terminals on the copper wires.

i think they had to put some kind of dope on the connections and maybe some contractors cheated by not using it. aluminum oxidizes easily so maybe there is the problem to the high resistance connection

[Terry M.]

Re: Copper Clad Aluminum ground cable

i think they had to put some kind of dope on the connections and maybe some contractors cheated by not using it. aluminum oxidizes easily so maybe there is the problem to the high resistance connection

We put and anti-oxidation compound on the outside connections, and then attach them with a gun operated by either hydraulics or a .22 shell.

The problem with the inside connections was those at the electrical devices under a screw. As the wire heated and expanded it reduced the cross section of the wire, which then made it loose and more heat, and so on and so on.

[Patrick H.]

Re: Copper Clad Aluminum ground cable

Patrick what is the length of your negative battery cable?

Approx 30 inches.

[Michael G.]

Re: Copper Clad Aluminum ground cable

The problem with aluminum electrical wire in house wiring was two-fold: it was caused by a combination of the oxidation of the aluminum and the loosening resulting from differences in expansion rates between the metals involved.

In the case of the Corvette ground wire, the expansion/contraction should easily be compensated for by the bolt stretch and/or spring washer built in to the attachment, (assuming it was properly tightened in the first place) but if the aluminum is counted on to create a ground path, the oxidation will still occur and cause a problem.

I think that there still is a product available at hardware stores that is designed to prevent the oxidation, but its been twenty years since I used it, so i don't know its name.

It's best to get rid of the aluminum.

[Clem Z.]

Re: Copper Clad Aluminum ground cable

The problem with aluminum electrical wire in house wiring was two-fold: it was caused by a combination of the oxidation of the aluminum and the loosening resulting from differences in expansion rates between the metals involved.

In the case of the Corvette ground wire, the expansion/contraction should easily be compensated for by the bolt stretch and/or spring washer built in to the attachment, (assuming it was properly tightened in the first place) but if the aluminum is counted on to create a ground path, the oxidation will still occur and cause a problem.

I think that there still is a product available at hardware stores that is designed to prevent the oxidation, but its been twenty years since I used it, so i don't know its name.

It's best to get rid of the aluminum.

use welding cable as we used that when we moved the battery to the trunk in drag cars and never had a problem starting engines with 14:1 compression ratio

[John H.]

Re: Copper Clad Aluminum ground cable

I used welding cable to make the battery cables on all of my project cars (Cobras, Grand Sport replica, etc.), with crimped and soldered copper lugs; still have the smack-it-with-a-hammer lug crimping tool. ZERO issues with welding cable - best conductor there is.