Cable manufacturing is a tedious and lengthy process that involves many necessary precautionary tests. Most of the cables are actually dependent on their protection rather than the conductivity of the conductor and its specifications. Priority is not to raise the amount of current flowing through the conductor but it is to raise the quality to sustain the current. To give preference towards the safe sustainability of electric current in the electric cables, certain tests are taken and a short circuit rating of the cable is printed over the cable.
To understand the short circuit rating of the cable we need to understand what short circuit among the conductors actually means. The short circuit within an electric cable means that both the bare conductors are in contact with each other. The current flowing from the complete path breaks the whole circuit and starts to move through a shorter path. A short circuit could occur due to the accidental occurrence of any tool, any object, any conductive material between both conductors.
Short circuit rating of the cable provides the information regarding the threshold short circuit value that the cable could easily withstand. In the short circuit, the motion of the electrons is totally arbitrary direction rather than the steady flow that they possess in a steady and normal condition. Some short circuit types are discussed as follows.
- Bolted Fault: This type of fault is pretty dangerous as it occurs when all the three phases are connected/bolted together having zero impedance in the circuit.
- Arcing Fault: This type of fault arises due to the gap in between the connecting electrodes. Obviously, the gap is very small but highest current pass through it and lose connection among the electric cables is the reason behind this fault.
- Ground Fault: This type of fault arises when a charged conductor material comes in contact with a ground conductor material. It allows the current to directly go inside the ground leaving the circuit incomplete. So, a protective circuit breaker is attached with this leakage current and makes the flow of current towards earth impossible.