What happens when you don't protect a power cable
04-11-03, 09:12 PM
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What happens when you don't protect a power cable
I recently made a repair on my father's car involving a car stereo installation that I did back in March, 2001.
First of all, an automobile is subjected to a wide range of environmental conditions; from below zero to over 100 degrees, sun, snow, ice, mud, rain, and salt. On the side, I install car stereo systems, from the basic headunit install to a full system with separate amplifiers and subwoofers. On March, 2001, my father's 1996 Mazda Millennia Sedan was in need an upgrade. Originally equipped with a Bose audio system, the CD changer was failing, and the rear speakers were crackling badly. We had some audio equipment on hand that was salvaged from my brother's car that was totaled January 2001. It was transferred to the new car, with the addition of a new set of 6x9 speakers in the rear deck.
The current setup consists of a Pioneer AM/FM cassette deck with CD player, two 30 watt/channel stereo amplifiers, Memphis audio 4 inch speakers in the doors, and 6x9s in the rear. The amps are powered by a 4-gauge stranded copper cable that runs from a fused source tapped directly off the battery to the trunk where the amps are.
Now, when I originally ran the cable (pics are attached), I didn't give any attention to protecting the cable from the elements. Part of the cable runs down the engine compartment, and up into a hole that is on the underside and into the passenger compartment (apparently for a clutch). I thought the wire's insulation would be enough to protect it. Famous last words.
Ok, two years later. A few days ago, my Dad's stereo has no sound. The head unit turns on, so I check the amps. Though I'm getting 12 volts at the remote turn on lead, I'm getting less than 3 volts at the main feed. I open the hood and check the fuse holder and I get 12 volts. What is going on? Well, just today, after the stereo worked for a while then failed, I look under the car and find that part of the cable had been rubbing against some odd nub on the underbody, which had worn away the insulation and exposed the copper conducts to the elements. The pictures show what's left of that section of the cable.
The corrosion had turned that part of the cable to dust-literally. Liberal amounts of the green powder fell to the driveway when I cut the bad section out. I took pictures of the damaged section so you can see how bad it was. It seems the only reason I got a reading at all was because somehow the powder was conducting electricity.
The solution was that I had to remove the old cable and run a new cable from the fuse holder in the engine compartment to the trunk. This time, I protected the section of cable that runs down the engine compartment and up into that hole with black flex loom, taped the ends with electrical tape to help keep out the elements, and zip tied the assembly to a bracket so that it wouldn't move.
The moral of this story: whenever you run a cable that'll be exposed to the elements, protect it!
First of all, an automobile is subjected to a wide range of environmental conditions; from below zero to over 100 degrees, sun, snow, ice, mud, rain, and salt. On the side, I install car stereo systems, from the basic headunit install to a full system with separate amplifiers and subwoofers. On March, 2001, my father's 1996 Mazda Millennia Sedan was in need an upgrade. Originally equipped with a Bose audio system, the CD changer was failing, and the rear speakers were crackling badly. We had some audio equipment on hand that was salvaged from my brother's car that was totaled January 2001. It was transferred to the new car, with the addition of a new set of 6x9 speakers in the rear deck.
The current setup consists of a Pioneer AM/FM cassette deck with CD player, two 30 watt/channel stereo amplifiers, Memphis audio 4 inch speakers in the doors, and 6x9s in the rear. The amps are powered by a 4-gauge stranded copper cable that runs from a fused source tapped directly off the battery to the trunk where the amps are.
Now, when I originally ran the cable (pics are attached), I didn't give any attention to protecting the cable from the elements. Part of the cable runs down the engine compartment, and up into a hole that is on the underside and into the passenger compartment (apparently for a clutch). I thought the wire's insulation would be enough to protect it. Famous last words.
Ok, two years later. A few days ago, my Dad's stereo has no sound. The head unit turns on, so I check the amps. Though I'm getting 12 volts at the remote turn on lead, I'm getting less than 3 volts at the main feed. I open the hood and check the fuse holder and I get 12 volts. What is going on? Well, just today, after the stereo worked for a while then failed, I look under the car and find that part of the cable had been rubbing against some odd nub on the underbody, which had worn away the insulation and exposed the copper conducts to the elements. The pictures show what's left of that section of the cable.
The corrosion had turned that part of the cable to dust-literally. Liberal amounts of the green powder fell to the driveway when I cut the bad section out. I took pictures of the damaged section so you can see how bad it was. It seems the only reason I got a reading at all was because somehow the powder was conducting electricity.
The solution was that I had to remove the old cable and run a new cable from the fuse holder in the engine compartment to the trunk. This time, I protected the section of cable that runs down the engine compartment and up into that hole with black flex loom, taped the ends with electrical tape to help keep out the elements, and zip tied the assembly to a bracket so that it wouldn't move.
The moral of this story: whenever you run a cable that'll be exposed to the elements, protect it!
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