Combinations of two or more electric conductor wires assembled by bonding, twisting or interwoven together are called electric wires. The stranding of multiple wires makes it more flexible than the solid wires of similar size. The electric cables are used to transfer electricity by connecting one end to a source and the other end to an electric device. These combinations of wires are placed in protective coverings that support the fiber. As the use of electricity and electronic devices are increasing rapidly, so are the electric cables required to run those devices.
The electricity cables are used in variety of purposes and therefore are installed as per the requirement, for e.g. to transmit for long distances and high voltage AC or DC current they could be routed overhead, underground, undersea. They could be fitted permanently in buildings or could be of temporary use of connecting of charging devices. As a single wired conductor can be used for multiple transmission purposes, it makes the installation economic and easy. Vacker Nigeria is a renowned supplier of electrical cables in Lagos, Abuja, Kaduna, Port Harcourt, Aba, Ibadan and Kano.
Cables and electromagnetic fields
Electromagnetic field is created by all kinds of conductors, when carrying current, such energy generated from the electromagnetic field is easily picked up other conductors placed within their range. Therefore even the electricity cables induce electromagnetic field and are also affected by other electromagnetic fields. The emission and up taking of such electromagnetic field produced by other devices hamper the performance of the device, that transmit surplus energy. This may affect other nearby devices or could even be to the different parts of the same device. This electromagnetic field and the unwanted signals produced might cause the other device to absorb unwanted noise, masking the desired signal. In some cases, they might even hamper the power supply cables to the extent where the equipment starts malfunctioning.
Keeping the length of the cables being used as short as possible, is the simplest way to control the disturbance caused by these electromagnetic field, because longer the cable, higher are the chances of picking up and transmitting of these unwanted signals. Similarly, placing the cables such as to avoid the range of other such affecting devices, reduces the problem. Apart from these general precautions, there are cables being designed to minimize the electromagnetic effect for the unavoidable cases. Three main designs being used for such cables are shielding, twisted-pair geometry and coaxial geometry.
The wire is encased inside a foil or wire mesh, throughout its length, thus decoupling the cable from any external unwanted electric fields. This is even more effective, if the cable is connected to a source of constant voltage, like the earth or the ground. This method follows the principle of faraday cage. However, this method is not so effective in case of low-frequency magnetic field. Nevertheless, this method of shielding is very effective on absorbing current leakage and capacitive current, which protects people from electric shock and also equalizes stress on the cable insulation.
This type of designing is mostly effective on reducing low-frequency magnetic field transmission and pick up. The design of the insulator being followed here is that the, foil or mesh shield has a circular cross section, placing the inner conductor at exact center. Here the magnetic field produced by the shield and the core conductor generate voltage, which are of equal magnitude, thus cancelling each other and avoiding any disturbance.
It is the combination of two wires or cables which are twisted around each other. In cases like these, the interference have longer wavelength than the pitch of the twisted pair. Hence, the interference is cancelled as the alternate lengths of wires develop opposing voltage.
As the materials being used as cable jackets are such types that easily pick up fire and are capable of spreading it, it is quite evident that they are one of the potential source of fuel for fires in the construction sites. Therefore, to avoid such accidents to happen, the cable jackets are used with coating materials or the jackets being used could itself be fire retardant.
In some cases, where the plastic protective covering could potentially be of danger than protection, the removal of such covering may also be carried out. Other ways of protection against probable fires could be inorganic coatings and use of boxes around cables. While using these kinds of protection, one should keep in mind that they also trap heat generated from the conductors which could be dangerous if the protection is not kept thin.
Apart from the fire retardant materials being used as insulators, non-combustible mineral insulation are also widely used to safeguard against fire, its cause and spreading.
Types of Electrical cables
Vacker Nigeria supplies electric cables in Lagos, Abuja, Kaduna, Port Harcourt, Aba, Ibadan and Kano. Depending on the construction, design and use of electric cables, they can be generally grouped as following:
- Coaxial cable
- Flexible cables
- Communications cable
- Non-metallic sheathed cable
- Direct-buried cable
- Heliax cable
- Portable cord
- Metallic sheathed cable
- Multicore cable
- Paired cable
- Twin lead
- Ribbon cable
- Shielded cable
- Single cable
- Twisted pair
- Submersible cables
- Twinax cables
These are the combination of different types of cables. Generally, the optical and the electrical cables are combined to create high performance as well as economic cables. They are typically used in FITA (fiber to the antenna), as the optical fibers does the work of carrying information and the electric conductors transmit electricity. Due to its diverse working capability it is used in various places like antenna mounted on towers or other such structures.
The hybrid cables are combination of various cables. However it is still considered a power cable due to its varying voltage and is not power limited. Therefore they must follow the standard procedures of clearance, separation and other standard safety rules as for the other power cables.