Views: 3 Author: Site Editor Publish Time: 2023-04-21 Origin: Site
The use of armor as a method of providing grounding for cable-powered equipment (a function technically known as the circuit protective conductor or CPC) is a matter of debate within the electrical installation industry.Sometimes the extra core inside the cable is designated as CPC (for example,instead of using a two-conductor cable for live and neutral and armor as a CPC,a three-conductor cable is used) or an external ground wire alongside the cable as a CPC.The main concerns are the relative conductivity of the armor to the core (which decreases with increasing cable size) and reliability issues.A recent article from an authoritative source analyzed this practice in detail and concluded that, in most cases, armoring is sufficient as a CPC under UK wiring regulations.
SWA BS 6724 cables
The construction of SWA cables depends on the intended use.For example, when power lines need to be installed in public areas, low smoke zero halogen (LSZH) equivalent cables known as SWA BS 6724 cables must be used.LSZH sheathing was mandatory for all London Underground cables following the 1987 fire at London's King's Cross station many fatalities were caused by inhalation of toxic gases and fumes.Therefore, it is now recommended to use cables in densely populated closed public areas.This is because they emit non-toxic levels of halogens and low levels of smoke when exposed to fire.SWA Cable BS 6724 Complies with the requirements of British Standard BS 6724 with LSZH liner and black LSZH sheath.
Armored cables are used in submarine communication cables to prevent damage from fishing boats and wildlife.Early cables carrying telegraphs were armored with iron wire, but steel wire was later used.The first of these was the cable laid across the English Channel by the Undersea Telegraph Company in 1851.More telegraphs, and later, telephone wires were soon followed by multicore wires. Modern cables are fiber optic cables rather than copper cores.The first transatlantic fiber optic cable was TAT-8 in 1988.
Electrical wiring is the electrical installation of cables and associated equipment such as switches, switchboards, sockets and light fixtures in a structure.Wiring must comply with safety standards for design and installation.Permissible wire and cable types and sizes are specified based on circuit operating voltage and current capabilities, and are further limited by environmental conditions such as ambient temperature range, humidity levels, and exposure to sunlight and chemicals.Associated circuit protection,control and distribution equipment within the building wiring system are governed by voltage,current and functional specifications.Wiring safety regulations vary by region, country, or region.The International Electrotechnical Commission (IEC) is attempting to harmonize wiring standards among member states,but there are still major differences in design and installation requirements.