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Wire Braid | What Makes Flat Braid Different From Round Braid?

Thursday, July 18, 2019

What is Wire Braid?

Braided wires are composed of a number of small strands of wire braided together that does not break easily when flexed and is the conductor of choice where flexibility is required. These wires are better conductors than solid wires and have a wide variety of applications including bonding straps, grounding, connecting moving parts, or as a cable shielding or protective covering. Wire braid is often made from copper, which can be bare or coated depending on the intended application. The most common option of wire braid is tinned copper thanks to its good conductivity, resistance to corrosion, and is easy to solder; but silver-plated and nickel-plated copper are both options as well. Starting as multiple strands of thin, flexible wire, the braided wire is created by winding on spools that rotate rapidly in a circular pattern around a core, weaving the wire together and shaping it into a flexible and strong braid.

Wire braid is invaluable in industries ranging from aerospace to mining because of its braided nature and flexibility is one of the most commonly cited benefits. The weaving of the fine strands gives the construction a range of movement that solid wire is unable to achieve. As for the size of a wire braid, that is determined by how many carriers the braiding machine has. A carrier is the main part of the braiding machine that holds the bobbin with wire, compensates for differences in length while keeping the tension constant, maintaining control if the wire is broken, and transports the bobbin around the track. The number of carriers in a single machine can be  16, 24, or 48, and depending on the machine, each carrier has a bobbin that can hold from 1 to 16 strands of wire or more. When looking at the construction info on the braid specifications, you can determine the number of carriers and wires per carrier by the three number identification system. The first number indicates the number of carriers while the second number indicates the number of wires per carrier and the last number is the gauge size of the individual wires (some may list the diameter in mm). An example of this would be 48-11-30 where 48 is the number of carriers, 11 is the number of wires per carrier, and 30 is the gauge of the individual wires.

Round (Tubular) Braid

Used in most industrial applications from automated and general types of manufacturing to renewable energy, round cables have long been the industry standard. The process above describes the method of creating a round braid, or tubular braid. Round braid is designed to maximize the amount of space within the smallest cross-sectional area required. This allows round cables to fit in most panels or machine openings that might otherwise be a problem for flat cable with an elongated cross-section. Tubular wire braid can be used as a shielding and protective covering that is 85% or more when placed over an equivalent diameter to the inside diameter of the tubular braid. When it comes to shielding, a round braid helps to protect from corrosion, impact, and electrical fields, while still ensuring the flexibility of the cable. Wire braid is able to handle a wide range of voltages, and even fluctuating voltages, due to their stranded construction and copper’s good conductivity.

Flat Braid

Although flat braided cables are currently a niche solution, they can offer a great way of supplying power and data to machines within the medical, semiconductor, and civil-aircraft markets, among others. Flat braid begins as round braid and is made flat by a pressure roller on the capstan, which is a large wheel that pulls the braid through the braiding machine. These braids are just as flexible and strong as round braid but have a larger surface area, which means that it has less resistance when electricity passes through it and should have low inductance overall due to having many individual strands in parallel. Flat braid cables need to be precisely weighed and balanced to make sure that movement is uniform. Used in both commercial and industrial settings, flat braid has many applications. They are a popular choice for grounding because of their ability to absorb shock and vibration, along with their extreme flexibility. Another application in which they flat braids are extremely useful is in lightning protection systems in which they are an important safety aspect of the system providing the lightning a low resistance path to the ground, generating little to no heat in the process. In other cases, it is sometimes used in radio settings, as the wider surface area of the strap has less radio frequency resistance or to electrically bond parts of a vehicle such as an exhaust pipe, door, or hood.

Both round and flat variants of wire braid can be found under a few different call numbers, including AA59569 Mil-Spec braid which was formerly regulated b the QQ-B-575 military specification. If you are looking for braided wire, check out our full line of wire braid specs and call your Allied Wire & Cable rep today at 800-472-4655 or submit an RFQ online.

Filed Under: Allied Encyclopedia

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