The trefoil arrangement is primarily used in situations where the three phases are carried by individual cables rather than a single three phase cable. ... Connecting the individual cables in the trefoil formation minimizes the magnetic field around the conductor and reduces the heating.

What does Trefoil cable mean?

Trefoil cable formation refers to the installed method for low, medium and high voltage power cables where three single core (phases) distribute the electricity supply rather than a single 3 core cable cable.

How does a single core cable control circulating current?

One way to mitigate this uncontrolled current is to earth only one end of the single core cable, but this then introduces a standing voltage at the unearthed end, which can be high enough to be hazardous. Using cross bonding with transposition helps reduce the circulating current / standing voltage.