NFPA 70E establishes the default arc flash boundary at 4 feet for low voltage (< 600V) systems where the total fault exposure is less than 5000 amperes-seconds (fault current in amperes multiplied by the upstream device clearing time in seconds).
An arc flash causes a very loud sound created by quickly-moving air, or a sound wave, that can reach 140 decibels at a distance of just two feet. Standard earplugs typically protect only up to 105 decibels, and you can go deaf from the intense arc flash sound.
Flash burns are like sunburn in the eye and can affect both your eyes. Your cornea can repair itself in one to two days, and usually heals without leaving a scar. However, if the flash burn is not treated, an infection may start.
Arc flash occurs when electrical current becomes uncontrolled, results in release of energy that ionizes air, releasing enormous heat, light, sound.
Degree of severity of burns is based on size and depth of the burn on human body. Fire, steam, Radiation, chemicals, Electric Arc, can cause burns.
Arc Blast is the supersonic shockwave produced when the uncontrolled Arc vaporizes the metal conductors and expanding Plasma.
Arc Flash occurs when insulation or isolation between electrified conductors is breached or can no longer withstand the applied voltage.
Typical safe ability of Transformer, Generator and Cable to withstand Isc – short circuit fault current in multiple of its In – rated current, without damage to the equipment.
I2t – Let through Energy is available thermal energy resulting from Current Flow during circuit opening in Fuse, MCCB, MCB.Unit is A2S (Ampere2 Second)
Severity Test for Assembly is Degree of impact a defect has on its operation, under conditions of high humidity combined with cyclic changes in temperature.
Load dispatch center is a coordinating agency for state electricity boards for ensuring a mechanism for safe and secure grid operation.
CTI is max voltage which material can withstands 50 water drops without without formation of conductive path.
Pollution factor can be solid, liquid, gaseous foreign matter which may reduce the dielectric strength accordingly Pollution Degree defined IEC 60664.
Microgrid is a group of interconnected loads and distributed energy sources within defined electrical boundaries that acts as a single controllable grid.
Clearance is shortest distance in air and Creepage is shortest distance along the surface of a solid insulating material, between two conductive parts.
In Practice there wiill always difference in phase displacement between primary and secondary currents, Allowed limits are defined in IEC 61869-2.
Current transformer Accuracy class is highest permissible percentage error at rated current for that accuracy class, as per IEC 61869-2 and IS 2705.
Power Quality Standard help us define acceptable limits for which Equipments must be designed to work and beyond which mitigation must be implemented.
Internal Arc Protection ensures Personal and ASSEMBLY protection under arcing conditions due to low impedance path, cause of electrical explosion.
Non Linear Loads are every where, which distorts the waveform, Hence analysis and Mitigation of Waveform Distortation / Harmonics is need of the day.
For Electrical Network with non linear loads, Voltage Distortion limits are defined in IEEE 519. To ensure Quality Power Supply to Assets, Mitigate !!
For Electrical Network with non linear loads, Current Distortion limits are defined in IEEE 519. To ensure Quality Power Supply to Assets, Mitigate !!