EWRB (Electrical Engineering) THEORY LATEST UPDATED.

EWRB (Electrical Engineering) THEORY LATEST
UPDATED.
State one reason why an earth fault-loop impedance test is carried out on
the socket outlet furthest from the main switchboard in a low voltage
electrical installation?
✔✔Any ONE of:
● To confirm that the electrical protection for the final subcircuit will
operate within the required time.
● To confirm that the electrical protection all other final subcircuits
supplied from the main switchboard will operate with the required time.
Define the term cut off characteristic as it applies to an HRC fuse.
✔✔This is the value of fault current that cuts off (operates) the fuse that
is less than the prospective short-circuit current.
A three-phase induction motor is controlled by a star/delta starter that
incorporates thermal overloads.
State one reason why HRC fuses are installed at the origin of the final sub
circuit supplying the induction motor.
✔✔To provide short-circuit fault protection to both the final sub circuit
and the motor