It's a flat, flat world, at least for two wire harness producers who said they expect copper consumption to remain level, or even decline, going forward despite the red metal being the material of choice for the increased wiring needed to support a growing array of "gadgetry" in new vehicles.
"Copper is the traditional metal for wiring. It is the metal of choice due to its properties. It is easy to use and very conductive," said Randy Sumner, innovation manager at Streetsboro, Ohio-based Delphi Electrical/Electronic Distribution Systems. However, given the price and weight of copper, plus the fact that you can fit only so much wiring into the wire harness without needing more space, "the need for wiring optimization is paramount," and that could affect the amount of copper used per electrical harness. "We are looking to minimize copper use to fit into the constraints that we have," Summer said.
Nevertheless, he acknowledges that demand for copper wiring per vehicle has been rising.
Eric Leszczynski, senior technical specialist with Yazaki North America Inc., Canton, Mich., agreed. "As automakers increase the gadgetry or 'wow' factor of their vehicles, it requires additional electrical circuits." And more electrical circuits per vehicle means more wire per vehicle, he said.
"About 99 percent of all automotive wire is copper, as it has been since the beginning of the automotive industry. Every now and then aluminum is mentioned as a substitute and it has been used in one car here and one car there, but copper remains the master."
While the long-term curve for the number of electrical circuits used per vehicle is clearly on the rise, it's very difficult to quantify, given that the number rises and falls at any given point in time, Leszczynski said. "Engineers are continually combining certain systems to lessen the cost associated with more copper wiring, which results in the elimination of some circuits. But then as new gadgets are introduced, the number of circuits goes up again. It's a give and take."
Currently, the average upper-end light vehicle has about 1,200 circuits, of which a good amount—probably 60 to 65 percent—is to power the drive system, he said. Much of the rest—about 30 percent—is used to process information for "infotainment," which includes navigational systems, DVD players and other electrical and electronic gadgets.
The pressure is clearly on the upside. This not only includes the circuits for gadgets installed into the vehicles themselves but those for all portable electronics—cell phones, laptop computers, portable navigation devices, MP3 players, satellite radios and televisions—that are brought into vehicles as plug-in devices, Sumner said.
"That drives the need for extra power outlet ports and receptacles in cars to charge or run these devices during the ride." Leszczynski said. "We never had 110-volt circuits in cars before, but now we are seeing household-type three-prong plugs as well as USB ports."
Some Ford Motor Co. vehicles, for example, are being equipped with SYNC, an in-car connectivity system that according to the Dearborn, Mich.-based automaker allows users to operate most popular MP3 players, Bluetooth-enabled cell phones and USB drives with simple voice commands.
Hybrid and electric vehicles, which are growing in popularity, also require a significant increase in wiring, Sumner said. "Wiring is needed to electrify the propulsion unit, which means that big wires with very high amperage and voltage are needed. That results in a lot of wire harness packaging challenges."
Besides all the added features, there are packaging challenges even in conventional, internal combustion engine vehicles. To deal with those pressures, as well as efforts to reduce weight and costs, Sumner said wire harness makers analyze all of the electrical circuits to keep the amount of copper to the lowest achievable level without compromising vehicle safety and functionality.
One thing that wire harness producers are doing is developing ever-smaller wire gauges. "About 12 years ago the thinnest gauge wire was 20 gauge," Leszczynski said. But now 22-gauge wire is commonly used, and preliminary steps have already been made to go down as far as 26 gauge. Going from 22 gauge to 26 gauge represents a 66-percent decrease in copper consumption as the wire is copper alloy rather than pure copper due to strength considerations, he noted.
Delphi Automotive Systems also has been working on a major program to develop aluminum circuits as replacements for copper, Sumner said, although he acknowledged that there are some disadvantages with aluminum—primarily that it is less conductive than copper and more prone to galvanic corrosion. "But it is lighter and less expensive," he said.
While aluminum wire would need to be one gauge size larger, it still would represent a massive cost savings compared with copper, he said. And while taking measures to protect aluminum wire from corrosion would add a little to the cost, it should still be less expensive than copper.
To date, the substitution of aluminum for copper circuits has been fairly limited. "We are just now starting to see some aluminum battery cables in some cars," Sumner said. "We are a few years away from seeing inroads in other wiring."
Leszczynskiis not so sure. Unless it is proven that the substitution would reap significant cost savings, he questioned whether aluminum would make any sizable inroads at all. Instead, he expects copper consumption for auto wiring in vehicles other than hybrids and electric cars to remain relatively flat as the increasing number of circuits offsets a decline in circuit sizes. MYRA PINKHAM