As a type of flexible armoured cable, braided wire is extremely useful when mechanical protection is needed without impeding cable flexibility. Not only does this flexibility allow braided cables to be used in more varied configurations and environments than standard armoured cables, but it also makes them much easier to install. As such, these cables are the preferred solution in industries that involve more complex cable installation procedures, such as the marine and offshore industries.
These braided wires are commonly referred to as galvanised steel wire braid (GSWB) cables to differentiate them from traditional steel wire armoured (SWA) cables. But what exactly is the difference between these types of armoured cables, and what are GSWB cables used for in particular? Keep reading to discover everything you need to know about steel wire braid cable.
What is an SWA cable?
A steel wire armoured cable is the traditional type of armoured cable, offering unparalleled mechanical protection for power cables in challenging environments. An SWA cable’s strength comes from its unique construction: first, a multicore power cable is covered by a protective layer of galvanised steel wires, which are robust and corrosion-resistant. These steel wires are wrapped (not braided) around the internal construction to ensure maximum coverage, which usually means at least 90% coverage. Then, an outer insulating layer, such as a polyvinyl chloride (PVC) sheath, is added on top of the armour to keep all components together and provide additional mechanical protection.
SWA cables are typically used in underground power networks due to their resistance to extreme weights, drilling, digging, and other types of impacts. However, the main downside associated with this strength and durability is that SWA cables aren’t very flexible, which makes them more difficult to install. The layer of steel armouring is also very thick and heavy, exacerbating these installation issues.
What is a GSWB cable?
To get around these downsides, galvanised steel wire braid cables – also known as GSWB cables, steel wire braid cables or simply braided wire – were developed as a more flexible alternative to SWA cables. As suggested by the name, the steel wire armouring is braided rather than wrapped around a multicore power cable, giving less overall coverage (usually around 80% coverage). This decreased coverage, combined with the braided structure of the steel wire, makes GSWB cables more flexible, allowing them to bend, flex and return to their original position with much more ease.
Want to learn more about GSWB vs SWA cables? Check out our complete guide to the differences between GSWB and SWA cables.
Steel wire braid cable properties
Let’s take a quick look at the defining properties of braided wire:
1. Mechanical strength
The braided wire creates a layer of protection around the power cable, shielding the internal conductors from physical stressors such as extreme weights (e.g. from being buried underground) or direct impacts from nearby drilling. This makes steel wire braid cables suitable for underground networks, powering underground public transport, powering marine and offshore facilities, and much more.
2. Flexibility
Since the steel wire armouring is braided rather than wrapped around the cable, it’s able to bend and flex much more than traditional steel wire armour. This allows these braided cables to be used in a wider range of environments, especially ones with more challenging configurations and installation requirements. Plus, these cables are able to flex without deforming over time, increasing their longevity.
3. Customisability
GSWB cables can be customised during the cable design process to achieve your desired level of mechanical protection and flexibility. By adding more steel wires and increasing the diameter of each wire, the level of mechanical protection can be increased, although this will negatively affect flexibility. If more flexibility is required, the number of wires and their diameters can be decreased – although, of course, this will reduce the amount of coverage and mechanical protection.
4. Weight
Even when the level of mechanical protection is increased, these cables still tend to be smaller and lighter than SWA cables. Combined with their improved flexibility, this means that these steel wire braid cables are even easier to install, making them a better choice for environments with more challenging installation requirements (such as marine and offshore facilities). Easier installation can also lead to cost savings if less time and resources are needed compared to the installation of SWA cables.
5. Corrosion resistance
The use of galvanised steel wires makes GSWB cables resistant to corrosion, allowing them to be used effectively in a wider range of environments. For instance, in harsh environments where cables are exposed to substances like oil, water and chemicals, GSWB cables have the strength needed to withstand these stressors. As a result, these braided cables are used frequently in marine and outdoor applications where other types of wires may be susceptible to excessive damage.
What are steel wire braided cables used for?
GSWB cables are commonly used in applications where both flexibility and resistance to mechanical wear and tear are needed. Therefore, if an environment involves both the potential of direct impacts (e.g. from underground drilling) in addition to the risk of wear and tear or cable deformation from cable movement, braided cables are a much better option than traditional SWA cables or non-armoured cables. Plus, in comparison to SWA cables, steel wire braid offers weight and diameter savings, resulting in a much easier installation process.
Consequently, these armoured cables are frequently used to install power networks in marine and offshore environments because of their ability to withstand these harsh conditions while remaining relatively easy to install, move and bend. They can also be used in machinery production environments, instrumentation and control. SWA cables are usually used as heavy-duty armoured cables in underground power networks, but where increased flexibility or easier installation is required, braided cables are also suitable for these environments.
However, braided cables should not be confused with shielded cables. GSWB cables are used for protection against mechanical factors and wear and tear as opposed to electromagnetic interference (EMI) cable shielding, which protects against signal interference from external sources (more on this later)
What is SY cable?
You may also hear about SY cables when discussing braided wire. Essentially, SY cables are the same as GSWB cables, except for the fact that they’re covered in a transparent PVC cable sheath. Not only does this transparent sheath provide extra coverage and protection for the internal conductors, but it also allows you to see any corrosion or damage to the cable straight away, helping you improve health and safety procedures on your site. SY cables are often used for instrumentation, production and assembly lines, and the power generation industry.
What’s the difference between an armoured cable and a shielded cable?
Armoured cables (like steel wire braid) are often confused with shielded cables since they ‘shield’ the internal construction of the cable from wear and tear, direct impacts and other external stressors. However, these two types of cables perform distinctly different functions.
When we discuss cable shielding, we’re actually referring to the process of shielding internal conductors from EMI, which can disrupt cable signals and therefore reduce their effectiveness. To create a shielded cable, a fine wire mesh – typically in the form of multiple plain or tinned copper fine wire strands that are woven together – is applied over the twisted conductors. This creates a screen around the conductors to block EMI, thus improving signal integrity and cable performance.
This metal screen does provide some mechanical protection, but the level of protection is not comparable to a proper armoured cable. If you’re not sure which type of cable is suitable for your project, get in touch with our cable construction and design experts to create a custom cable solution that’s ideally suited for your environment and requirements.
Here at Custom Designed Cables, we’re able to design, manufacture and test custom cables for a wide variety of industries, ensuring that your new cable solution delivers the results you need whilst also complying with national, international or industry regulations where relevant. Contact us today for an initial consultation, or visit our blog to discover additional in-depth cable guides.
