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On a 250 volts supply,a fault having a resistance of 20 ohms develops between the unearthed end of the winding of an electric heater and...

On a 250 volts supply a fault having a resistance of 20 ohms develops between the unearthed end of the winding of an electric heater and the frame.If the resistance of the substation earth electrode is 4 ohms,that of human body 2000 ohms and the safe maximum current through the body is 0.025 Amperes,what is the safe maximum resistance of consumers earth electrode?

Answers

Kevin
voltage drop across human body=IR=0.025*2000=50 volts
voltage between point a and b=250-50=200 volts
current=200 volts/[4+20]=0.025*R/[R+2000].
200[R+2000]=0.025R[4+20]
R=6 Ohms
Kevinsenzoochieng answered the question on October 21, 2019 at 19:57

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