why there is a fault occurs, if a phase wire touches ground..
and the fault not occurs when we connect a bulb between phase
and ground..??



why there is a fault occurs, if a phase wire touches ground.. and the fault not occurs when we con..

Answer / 7anoter4

Let's say the cable supplying the outlet [phase-neutral-
ground] is 3*14 awg copper and the length up to supply
panel is 300 ft. The conductor resistance is about 1 ohm[at
rated temperature].For 120 V voltage supply at panel if the
phase contact the grounding conductor the current will be
120/2=60 A. A 15A fuse will burn in less than 1 sec.
However, usually the short circuit current is 500-1000A.
If a bulb is connected between phase and ground ,for a 100
w bulb 120 V the resistance will be 120*120/100=144 ohm.
The current will be 120/144=0.83 A.

Is This Answer Correct ?    7 Yes 0 No

Post New Answer

More Electrical Engineering Interview Questions

why threre are two parallel lines in transformer's symbol?

11 Answers   NTPC,


What is a system?

0 Answers  


what are the ratings of sockets?

10 Answers   L&T,


Explain the propagation of harmonics in the network and influence of phase angle of harmonics.

0 Answers  


If 440 V supply has given at the secondary winding of transformer at that time if we apply 11 KV at primery then what will happen???????

4 Answers  






according to faraday's law whether the induced emf is average or rms value?

2 Answers   Power Grid,


what is the ms flat constant for calculating earth mat design calculation?

0 Answers  


can induction motor becomes as a generator. if yes how it is possible. if there is a squirrel cage rotor.

6 Answers  


In a d.c circuit, if current and resistance are known, power (P=I*I*R) can be determined. This relationship also applied to an a.c circuit. Comment the reason for this.

3 Answers  


will we get shock from dc?

12 Answers   L&T,


What is the principle of Excitation.

1 Answers  


What is the difference between PLC and Embeded system

0 Answers  


Categories
  • Civil Engineering Interview Questions Civil Engineering (5085)
  • Mechanical Engineering Interview Questions Mechanical Engineering (4451)
  • Electrical Engineering Interview Questions Electrical Engineering (16632)
  • Electronics Communications Interview Questions Electronics Communications (3918)
  • Chemical Engineering Interview Questions Chemical Engineering (1095)
  • Aeronautical Engineering Interview Questions Aeronautical Engineering (239)
  • Bio Engineering Interview Questions Bio Engineering (96)
  • Metallurgy Interview Questions Metallurgy (361)
  • Industrial Engineering Interview Questions Industrial Engineering (259)
  • Instrumentation Interview Questions Instrumentation (3014)
  • Automobile Engineering Interview Questions Automobile Engineering (332)
  • Mechatronics Engineering Interview Questions Mechatronics Engineering (97)
  • Marine Engineering Interview Questions Marine Engineering (124)
  • Power Plant Engineering Interview Questions Power Plant Engineering (172)
  • Textile Engineering Interview Questions Textile Engineering (575)
  • Production Engineering Interview Questions Production Engineering (25)
  • Satellite Systems Engineering Interview Questions Satellite Systems Engineering (106)
  • Engineering AllOther Interview Questions Engineering AllOther (1379)