Electrical Geeks

Introduction: In HT electrical distribution, the system can be earthed or unearthed. The selection of earthed/unearthed cable will depend on system. If distribution system is earthed then we have to use cable which is manufactured for earthed system. (Which the manufacturer specifies). If the system is unearthed then we need to use cable which is manufactured for unearthed system. The unearthed system requires high insulation level compared to earthed System. For earthed and unearthed XLPE cables, the IS 7098 part2 1985 does not give any difference in specification. The insulation level for cable for unearthed system has to be more. Earthed System:            Earlier the generators and transformers were of small capacities and hence the fault current was less. The star point was solidly grounded. This is called earthed system. In Three phases earthed system, phase to earth voltage is 1.732 times less than phase to phase voltage. Therefore voltage stress on cable

 here, u can get electrical engineering question and answers and multiple choice questions and interview questions part - 1 1)     Why ELCB cannot work if Neutral input of ELCB does not connect to ground? ELCB is used to detect earth leakage fault. Once the phase and neutral are connected in an ELCB, the current will flow through phase and that same current will have to return neutral so resultant current is zero. Once there is a ground fault in the load side, current from phase will directly pass through earth and it will not return through neutral through ELCB. That means once side current is going and not returning and hence because of this difference in current ELCB will trip and it will safe guard the other circuits from faulty loads. If the neutral is not grounded fault current will definitely high and that full fault current will come back through ELCB, and there will be no difference in current. 2)     What is the difference between MCB & MCCB, Where i

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here u can get all electrical units and if u want any more u can comment below. GENERAL,ELECTRICAL,ELECTROSTATIC QUANTITIES Unit Sy mbol General Quantitie s m/s 2   (metre/second/second) a Acceleration, linear m 2   (square metre) A Area J (joule) W Energy or work N (newton) F Force m (meter) l Length kg (kilogram) m Mass W (watt) P Power Pa (pascal) p Pressure K or °C (Kelvin or degree Celsius) θ Temperature value s (second) t Time Nm (newton metre) T Torque rad/s (radian/second) ω Velocity, angular m/s (metre/second) v  or   u Velocity, linear m 3   (cubic metre) V Volume m meter λ Wavelength Unit Symbol Electrical Quantities Ω(ohm) Y Ad