Factors affecting Clerance :
Factors affecting Crepage :
Circuit Breaker with Short Time withstand Icw capacity are Calassified as Category B (eg. ACB), and without Icw are Category A (eg. MCCB, MCB).
Arcing Class A, B, C according to personal protection from ASSEMBLY under Arc Fault and ASSEMBLY protection from internal Arc fault.
Tested Assemblies Varification Tests as per IEC 61439. Verification by TESTING, CALCULATION, DESIGN-RULES for Construction and Performance of ASSEMBLY.
Arc Flash is light and heat produced as a result of Arc Fault, due to low impedance path, which causes electrical explosion or discharge.
Utilization Categories indicate the type of Load and Duty Cycle of the load basis which selection of Switchgear should be done for the intended application.
CTI is max voltage which material can withstands 50 water drops without without formation of conductive path.
Nonconducting material that provides electric isolation of two parts at different voltages.
It must have an electrical resistivity and a dielectric strength sufficiently high for the given application.
The secondary requirements relate to thermal and mechanical properties.
IEC 61439, Low Voltage Power Switchgear and Controlgear ASSEMBLIES. Discrimination between TTA and PTTA eliminated by verification approach.
Current transformer Accuracy class is highest permissible percentage error at rated current for that accuracy class, as per IEC 61869-2 and IS 2705.