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Making 12-V Power More Reliable

With the heavy use of 12-V accessory devices in applications from automotive to industrial, it’s crucial that design engineers know the quality of device they’re using, especially imported products that may not go through proper testing.

Modern society requires 12-V power for numerous applications, ranging from automotive and marine to cell phones, notebooks, PDAs, and various consumer and industrial products.

Common 12-V wire and cable applications typically require the use of various accessories. These include plug-in power cord sets; coiled cord sets; extension assemblies; cigarette plug splitters, adapters, and sockets; covered cigarette plugs and sockets; high amperage cigarette plugs; marine plugs; fuse clips and holders; cable assemblies; vibration-resistant assemblies, automotive antenna plugs, and sockets; automotive fuse clips; and general fuse holders.

Significant quality differences exist between top-quality and inferior-quality 12-V accessory devices, so design engineers and procurement professionals need to recognize whether the price being paid equates to the value being received. That’s because many imported products are improperly tested and fail to meet applicable requirements, including UL-rating, CL2 and CL3 electrical codes, and MIL-grade standards, to name a few.

Impact of Copper Price Volatility

The cost of 12-V wire and cable products and accessories tend to fluctuate based on the price and availability of copper and the volume of raw materials required to construct a particular device. For example, an automotive 12-V cord set is normally made with twin copper wires and in lengths from 3 to 15 feet. Those that use heavier gauge copper wire in longer lengths tend to be more impacted by fluctuating copper prices, mainly due to the larger volume of raw materials.

Global copper prices remain stable and are predicted to move upward as demand grows. However, the situation is being exacerbated by higher tariffs currently being imposed under the current U.S.-Chinese trade dispute.

Ensuring a Reliable Electrical Connection

The choice of materials utilized in a 12-V plug set determine how efficiently electricity will be conducted. Generally speaking, wires plated with less expensive materials are more likely to corrode and/or oxidize, thus causing increased electrical resistance. By contrast, better quality materials such as gold plating offer greater protection against corrosion, vibration, heat, shock, humidity, and pressure.


Loss of an electrical connection, even for microseconds, can result in a loss of power and possible system failure.

To prevent this from occurring, start by utilizing better quality wire and cable along with corrosion-resistant plating, which is especially recommended for portable devices that may be exposed to the elements.

A well-designed 12-V plug will resist shock and vibration while also allowing for easy removal without tools. If a 12-V plug is to be inserted and extracted hundreds or even thousands of times over its lifetime, then it should be designed for durability by maintaining a sufficient amount of retention forces. However, you should avoid a solution that requires excessive retention forces, as it may result in long-term wear to the contact surface.

Understanding Real-World Tradeoffs

If long-term reliability is important, then it’s essential to conduct thorough due diligence when evaluating potential suppliers of 12-V wire and cable products. Choosing a reliable supplier is critical especially when premature product failure could put an OEM at risk for costly repairs, rework, warranty returns, loss of reputation, and product liability claims. It pays to spend a little extra for high-quality materials to ensure greater customer satisfaction.

At the same time, you can’t design in a vacuum. Product design invariably involves tradeoffs: size and weight constraints versus durability; ease of insertion and removal versus ability to retain the plug under rigorous conditions; durability of materials versus component cost; etc. A time-proven method for enhancing product safety and dependability is to equip the 12-V device with a replaceable fuse. Unfortunately, this simple safety step is too often ignored, as most people are unaware of just how frequently 12-V devices experience energy spikes.

For instance, automotive electrical systems experience positive and negative energy spikes whenever power shifts from the starter to the alternator. Batteries work like a large capacitor to soften these spikes, with replaceable fuses providing added protection for sensitive components and circuitry.

Use of a replaceable fuse is especially recommended for 12-V devices that travel internationally to locations where the power grid is unreliable and frequent power surges and brownouts occur.

Tom Blaha is President of Memory Protection Devices.

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