why earth hole size is biggest in plug point?
Answer Posted / rd dadhich
Who so ever are thinking of low resistance as cause of
bigger hole means bigger earth pin are forgeting the point
that the same earth current on fault is flowing through the
Phase pin and connecting wires , whose area is very less
compared to earth hole or Pin , are also carrying that
fault current and are suitably rated accordingly .
The correct reason is :-
1. While inserting equipment first get earth
connection.as pin goes first and so equipment is
earthed before supply is given
2.While withdrawing the plug the earth connection
disconnects in last. Power disnnect first and
earth in last
Reason of earth Pin larger in diameter than other pins in a
plug socket :-
Accidently also one can not inser earth pin in other
pins .
Both the above features are for foolfroop safety & no other
reason like low restance etc
| Is This Answer Correct ? | 16 Yes | 3 No |
Post New Answer View All Answers
HELLO EVERYONE, I RECENTLY HAVE FOUND ONE PROBLEM, I WAS TAKING NO LOAD TRIAL OF AN HT MOTOR 920 MOTOR , 1440 RPM , 6.6 KV, WITH AUTO TRANSFORMER. AT 450 V, LOAD WAS 40 AMP AND SPEED WAS 250 RPM. BUT AS WE INCREASE VOLTAGE FROM 450 TO 480V, LOAD BECOME 41 AND SPEED REDUCED TO SOME RPM . SO WHICH PHENOMENON ACTED HERE FOR REDUCING SPEED.?? AND IS IT HAPPENING ALWAYS OR IT IS RARE? I ALSO HAVE FACED SUCH PROBLEM WITH FEW LT MOTOR ALSO.
In CTs tan delta point should be earthed , what is the reason behind it?
What is negative sequence over voltage element?
what is positive , negative & zero equivalent system resistance
sir iam from electrical and electronics branch ,can i appear for the hpcl offline requirtment? if yes please mail me on vikram_raju25@yahoo.co.in
How much current will a 5 HP delta connected motor at no load will take?Is tat need a starter
What is the function of the circuit breaker failure relay?
Can any body tell me the different types of LT cables & their application.
What is the resistance of the field winding of a d.c. Shunt generator kept low?
Is potential difference materials property ..? if yes tnen how.. explain brifly.
how do prepare ongc exam.how is it question model.i am electrical. which part covering in electrical.tell me
Why need 3phase machine double earthing?
What is center gravity load in substation?
What information we need to prepare relay coordination chart
How can you sized or estimate the ligthning arrester current rating?