The arc-fault circuit protection

In electrical power systems bolted short-circuits are rare and the fault usually involves arcing and burning; mostly the limit value of minimum short-circuit depends really on arcing-fault. In AC low voltage systems, the paper examines the arcing-fault branch circuits as weak points. Different protection measures are available against the arc-faults. A first measure that can guarantee a probabilistic protection is allowed by the adoption of overcurrent protective devices (OCPD), optimizing the design of the structure of the system and/or the coordination of protection. A well known complete protection is allowed by adopting are-fault circuit interrupters (AFCI) for the protection of branch circuits. The authors suggest a new complete protection allowed wiring the branch circuits, including particularly extension cords, with special power cables, protected by ordinary ground fault protective devices (GFPD). The suggested design for single-core or multi-core power cables is that each insulated core has a concentric conductor shield. Converting the line-to-line fault into a line to ground fault or into a mixed type is the goal of this special cable type Faults Ground-Forced Cable (FGFC).