Electrical and mains power cables are present in all applications that require power or lighting. When selecting a cable system, additional knowledge is required for smooth operations. This knowledge consists of the cable system’s service conditions, construction, type of load served, mode of operation, maintenance and the like.
Whatever industry you’re in, here are the key factors in selecting the most suitable cable system for your application.
Power cables in Singapore can be used for indoor or outdoor installations, depending on the load served and the distribution system. A good understanding of local conditions, installation personnel and maintenance crews is vital to ensure that the cable systems will operate properly. Often, cable insulation becomes weakened or damaged during installation due to incorrect application of pulling tensions. If you have a competent installation and maintenance team, you reduce network downtime and there’s a lower possibility of connectivity errors.
The type of cable construction required for a specific installation bears upon your selection of power cable. Cable construction, meanwhile, involves conductors, cable arrangement, insulation and finish covering.
- Conductors — Conductive materials such as aluminium and copperare used based on their workmanship, environmental conditions they will be subjected to and maintenance.
- Cable arrangement — Conductors can be arranged to form single-conductor or three-conductor cables. Single conductors are relatively easier to install and splice. They can also be used to form multiple cable circuits. On the other hand, three-conductor cables contain ground wires that provide the lowest impedance path.
- Insulation and finish covering— This is generally based on the installation type, service conditions, ambient operating temperature and type of load served. In some installations, unusual conditions may be present such as a corrosive atmosphere, presence of oil and solvents, insect and rodent hazards, extreme temperatures and presence of ozone.
The cable’s insulation needs to withstand the voltage stresses experienced during various operating conditions. Cable insulation selection is based on the appropriate phase-to-phase voltage and the general system category is classified as 100%, 133% or 173% insulation levels.
Cable size selection is dependent upon the following factors: current carrying capacity, short circuit rating and voltage regulation.
- Current carrying capacity — this is based on the cable’s thermal heating
- Short circuit rating — cable size is checked for its capability to withstand short circuits and thermal damage
- Voltage regulation — voltage drops are checked to ensure correct load voltage
Shielded power cables offer more protection than standard unshielded ones. In power systems where there is no metallic or shield covering, the electric field is partly in the insulation system and partly in the air. If the electric field is intense, as in the case of medium and high voltage, surface discharges will occur and cause air particle ionization. The shielding in power cables mitigates the potential of serious safety hazards and increases the reliability of the cable circuits.
High-Grade Offshore Power Cables from Cable Source
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