a) False. The principle of operation of a three-phase and single-phase core balance Earth leakage relays is different. Three-phase relays detect the imbalance in the current between all three phases, while single-phase relays detect the imbalance in a single phase.
b) False. In a three-phase four-wire system, the neutral conductor must also be broken by the Earth leakage relays when it operates to ensure the safety of the system.
c) False. Earth leakage relays in a three-phase installation do not trip solely based on load imbalance. They trip when there is a leakage current to earth, which can be caused by faults or insulation breakdown.
d) False. Three-phase Earth leakage relays typically have a test circuit to allow for routine testing of the relay's operation and sensitivity. Testing the relay regularly is important to ensure it will function correctly during an actual fault situation.
Are the following statements true or false. Give a reason for each
a)The principle of operation of a three-phase and single-phase core balance Earth leakage relays is similar
b)Only the live conductors of three-phase four-wire system must be broken by the Earth leakage relays when it operates
c) in a three-phase installation, the Earth leakage relays will trip if the load is not properly balanced
d) a three-phase Earth leakage relays does not have test circuit
1 answer