ARC FLASH PROTECTION
An arc flash is a powerful and dangerous occurrence where an electric current leaves its anticipated path and travels from phase to phase, or phase to ground. Most injuries caused during an arc flash are a result of wearing flammable (non-flame-resistant) clothing that ignites and burns against the skin.
Generally, an arc flash results from either a phase to ground or a phase to phase fault during following activities:
• Phasing Operations – especially MV-HV systems at 11kV, 33kV, 66kV, 132kV+
• High Impedance Faults – Hi-Z arcing on overhead, substation and distribution feeders
• MV HV Switchgear – opening/closing breakers and fused switches
• Fusegear – changing fuses on LV distribution, street lighting and service feeder pillars
• DC Battery Storage – opening doors/covers on systems during maintenance
• Circuit Breakers – power racking is HRC4 task with arc rated clothing rated at 40 calories/cm2
• Live Cables – excavation, fault finding, jointing near exposed LV and 11kV-33kV conductors
• Jointing Cables – working in trench, substation and on link-boxes
• 33kV Substations – testing and survey of cable terminations, RMU, transformers
• High Voltage Flashovers – opening high voltage switchgear, cable boxes, cabinets and panels without following correct isolation procedures or obtaining necessary authorisation permits
Arc flash clothing is typically used when working on switchboards, panelboards, industrial control panels and motor control centres at low, medium or high voltages.
