If the electrical cable concerned needs to be rugged, well cabled, and robust, then there is no other than Steel Wire Armoured (SWA) cable to be the exception to the rule. From connecting a shed to cabling an industrial factory plant to using under-floor wiring, the material used is SWA cable by expert electricians and even by any do-it-yourself professional who ever desires an SWA. Then what exactly is SWA armoured cable, and why does everyone use it?
Throughout this comprehensive guide, we'll take you through everything that you would want to know about SWA armoured cable—its composition and applications to installation tips, specifications, and safety concerns.
What is SWA Armoured Cable?
SWA cable, as explained by SWA Cable Suppliers, is a mains electricity cable used where the cable must be buried underground or exposed to mechanical stress. The most typical feature of SWA cable, which distinguishes it from any other cable, is its armour of steel wire—a galvanized steel wire covering over the cable core.
The armour serves two functions:
- Mechanical protection—abrasions, impacts, or rodent attacks.
- Earthing—in the majority of applications, the armour itself can double as an earth conductor.
SWA cable typically consists of the following layers:
- Conductors (often copper): These transmit the electric current.
- Insulation: Often XLPE (Cross-Linked Polyethylene) or PVC.
- Bedding: Layer to shield internal insulation from steel wire.
- Armour: Steel wire helically wound for protection.
- Outer sheath: Often a black PVC jacket to prevent moisture and corrosion.
General Applications of SWA Cable
SWA cables are predominantly used for usage and can be applied to various uses, residential and commercial. Some of its most significant applications are:
- Installation Underground: The SWA cable is best equipped to be installed straight underground with no extra conduit or trunking. Steel armour wire provides grounding against undesired impression while excavating and also pressure and soil displacement.
- Power and Outdoor Lighting: Whether for security lights, external sockets, or providing power to a garden office, SWA cable is weatherproof and long-lasting.
- Industrial Buildings: Factories, warehouses, and building sites would normally use SWA to energize heavy-duty machinery, conveyor belts, and light bulbs.
- Renewable Energy Systems: SWA cables are mostly used in solar and wind energy systems used in the transmission of power from the place of generation to the main distribution board.
- Temporary Power Supplies: Festivals and events utilize the SWA cable for temporary safe and secure power installation, specifically where physical damage or injury is most probable.
SWA Cable Types
SWA cable comes in various types by conductor size and core number:
Core Number
- 2 Core—Normally lighting or single-phase equipment.
- 3 Core—Single phase with earth conductor.
- 4 Core—Three phases without an integral earth.
- 5 Core—Applied in three-phase earth and neutral systems.
- Multi-core—In installations of special control or control cables.
Conductor Sizes
Cable sizes would typically range between 1.5mm² and more than 400mm², depending on the load current and application. The larger the cable size, the more current a cable can carry.
Standards and Regulations
In the UK, SWA cable must be to British Standard BS 5467, which specifies the manufacture, performance, and testing of armoured power cables with thermosetting insulation.
Some of the other legislation and standards are:
- IEE Wiring Regulations (BS 7671)—Enabling safe installation and use.
- Building Regulations—Particularly Part P for domestic property work.
- Electricity at Work Regulations 1989—For protection of workers.
Always use a licensed electrician so your work is current with today's standards and code for your specific work.
Benefit of SWA Cable
There's a reason that SWA is first on so many lists. It has numerous benefits:
Durability
The steel wire armour gives the cable resistance against crushing, cutting, and exposure to external mechanical abuse.
Weather resistance that is superior
As it is generally supported by its outer sheathing, SWA cable finds optimal application for outdoor and underground installations.
Fire Resistance
With their excellent heat resistance, XLPE-insulated cables are quite safe to be utilized in applications having quite high temperatures.
Flexibility
It can be particularly tailored to virtually any profession, from extremely small household work to extremely large industrial installations.
Security
Through the use of armoured cable, electric shock as well as electrical fire is minimized, particularly in the event of risk exposure in an environment.
Restrictions and Conditions to Observe
SWA cable is very rugged but cannot be utilized for anything. For which reasons the following are to be blamed:
Not Flexible
SWA cable is very rigid, and thus bending it into tight turns or sharp bends might be more challenging.
More Bulky and Heavy Than Regular Cable
The steel wire adds to the weight of the cable, which might need extra support when installing.
Heavier
Because of its weight, SWA cable needs extra support when being installed.
More Costly
Because of its materials and production, SWA cable is more expensive than PVC cables.
Needs Proper Termination
You need specialized glands and equipment to effectively end SWA cable, and that's a learning curve for some home DIYers.
How to Install SWA Cable?
SWA cable must be correctly installed for safety and functionality. The following is a general guide:
- Plot the Route: Cable route should be marked so that it will not pass over any potential hazard such as water pipes or gas pipes.
- Prepare the Ground (for underground runs): Excavate a trench at least 450mm deep (600mm if it is beneath a driveway) and lay a bed of soft earth or sand.
- Cable Laying: Bundle the SWA cable within the trench and cover it with a cover layer. Cover the cable with cable marker tape to alert future excavators.
- Cable Fixing: If it is terminated on the surface, support the weight using heavy-duty clips or cable trays.
- Termination by Glands: Use complete termination with SWA cable glands. The glands retain the armour and offer very good electrical contact for grounding.
- Installation: Testing Ensure a competent electrician tests the installation for insulation resistance, continuity, and earthing prior to energizing.
Maintenance and Safety Tips Routine Inspection
Check for wear, corrosion, or mechanical damage.
- Do Not Overload: Ensure the cable can support current usage of the appliances or systems to be powered.
- Avoid Sharp Bends: These will naturally reduce the inner insulation over a period of time.
- Dry Out: Although SWA is weather-resistant, long soaking can degenerate the outer sheath.
- Label Clearly: Label voltage and destination of circuits with identification tags or markers.
Conclusion
SWA armoured cable is a rugged cable for hardwiring applications. With its enhanced mechanical protection, weather resistance, and use underground or outdoors, it's the professional's preference and serious DIYer's first option. Understanding its construction, use, installation needs, and safety factors will have you making informed decisions and have your project safe and compliant. Whether you're illuminating a garden, powering a workshop, or wiring an industrial factory, SWA cable is the dependable beginning that does the job.
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