If you are about to purchase wire or cable for the first time, or even if you have purchased it in the past, you may find the task daunting. After all, most distributors stock thousands of wire and cable products. Your application may require ribbon cable, but which specific ribbon cable should you buy? Having choices is important, but with so many choices, decision-making can become overwhelming.
Do you know what questions to ask? Before beginning a search, equip yourself with the right knowledge. Background information combined with basic preparation can give you some command during the buying process. In the article, "Specifying High-Performance Cables: The Devil Is In The Details," by Alpha Wire Company, they evaluate four main issues to be considered. These are cable shielding, flexibility, chemical resistance, and temperature range.
Shielding
When purchasing cable, be sure to explore cable shielding. Shielding ensures that the electrical process runs smoothly. An engineer will tell you shielding minimizes problems of signal exit or entrance caused by interference. Types offered include braid, foil, spiral, or a combination braid/foil shield. Each type has advantages and disadvantages: - Foil Shields:
- Uses: CATV, MATV, Video, computer I/O cables
- Advantages: 100% cable coverage, low weight and low cost
- Disadvantages: High DC resistance and lower mechanical strength
- Braid Shields:
- Uses: Computers to terminate interconnect for process or control applications
- Advantages: Great structural integrity, flexibility and flex life
- Disadvantages: Does not provide full coverage, heavy
- Spiral Shield:
- Uses: Microphone, audio cables and retractile cords
- Advantages: Great flexibility and flex life
- Disadvantages: Not effective above audio frequency range
- Combination Shields:
- Uses: Video, CATV, MATV, networking, computer I/O cables
- Advantages: 100% foil coverage, strong and low resistance
- Disadvantages: Higher cost than other shields
Chemical Resistance
An engineer will tell you that electrical cables possess various levels of chemical resistance, but there may be more to it. You should know which chemicals could present a potential problem in the entire lifespan of your cable. Also, consider that oils and corrosive chemical vapors or liquids could potentially enter into the cable connections. Any type of chemical intrusion could lead to cable failure. You might need to add additional sealing to prevent moisture permeation.
Temperature
Temperature range is another essential factor in the mix of things. What temperatures will your cable need to withstand to be effective? You may find that a cable possesses all the necessary electrical features required for extreme temperatures, but will it be able to adapt to the physical demands associated with that temperature?
Flexibility & Flex
A flexible cable can make installation and troubleshooting much easier. However, did you know that "flexing" is a different issue that needs to be addressed? Due to the nature of many manufacturing applications, cables may encounter constant flexing. Particular cables are built better for this than others.
Conclusion
There is more to finding the ideal cable than meets the eye. Don’t be intimidated by choices. A cable exists for just about every environment and application if you know what to look for. Spend some time asking the right questions and consider every angle.
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