Wire Braid Construction
Wire braid is often made from copper, which can be bare or coated. Though silver-plated and nickel-plated copper are both available options, tinned copper is the most common, thanks to its good conductivity, resistance to corrosion, and easy soldering. A braided wire starts as multiple strands of thin, flexible wire. This wire is then wound on spools that rotate rapidly in circular patterns around a core, weaving the wire together and shaping it into a flexible and strong round braid.
The size of a wire braid is determined by how many carriers the braiding machine has. Typically, there are sixteen, twenty-four, or forty-eight carriers in a machine. Each carrier has a bobbin, which can hold from one to sixteen strands of wire or more, depending on the machine. You can tell how many carriers and wires per carrier are used to make a particular braid by looking at the construction info on the braid specs. The construction is usually written as three numbers (such as 24-4-36):
- 24 = The number of carriers
- 4 = The number of wires per carrier
- 36 = The AWG of individual wires (some may list the diameter in mm)
A flat braided wire begins as a round wire braid and is made flat by a pressure roller found on the capstan. A capstan is a large wheel that pulls the wire through the braiding machine. A flat braid is just as flexible and strong as a round braid, but it has a larger surface area, which means it has less resistance when electricity passes through it.
Wire Braid Uses
Wire braid is invaluable in many industries from aerospace to mining. Flexibility is one of the most commonly cited benefits of braid wire. The weaving of the fine strands gives the construction a range of movement that solid wire is unable to achieve.
Tubular wire braid is useful as shielding in cable applications, as it can protect from corrosion, impact, and electrical fields, while still ensuring the flexibility of the cable. Copper wire braid, in particular, finds great use as a conductive shield in coaxial cables. Thanks to the stranding and copper’s good conductivity, the wire braid is able to handle a wide range of voltages, and even fluctuating voltages, which makes them popular in modern-day circuits.
Flat braided wire, like its tubular counterpart, also sees a range of uses in commercial and industrial settings. It is a popular choice for grounding because of its flexibility and ability to absorb shock and vibration. It is especially useful in radio settings, as the wider surface area of the strap has less radio frequency (RF) resistance. In addition, flat braid wire is commonly used in lightning protection systems. The braid is an important safety aspect, as it provides the lightning a low resistance path to the ground, generating little to no heat. This feature prevents hazardous conditions that might cause fires and keeps buildings safe from the dangers of lightning strikes. Wire braid, in both round and flat variants, is sold under a few different call numbers, including the popular AA59569 mil-spec braid, formerly regulated by the QQ-B-575 military specification.