Ground Clearance: This is the minimum distance between any live conductor and the earth or ground.
Phase Clearance: It is the clearance between the different phases in a circuit or same phases in different circuits
Sectional Clearance: This is the minimum clearance between the live conductor and the limits of work, where spacial clearance is related to the safety of the operating personnel. The limits of work section may be ground or the platform on which the person is working.