Differentiate creepage distance from clearance distance.

• A. Creepage distance is the surface path length along the insulator; clearance is the shortest straight-line distance through air between conductors.
• B. Creepage distance is the straight-line air gap; clearance is the surface path length along the insulator.
• C. Creepage distance is the distance around the insulator; clearance is the distance through the insulator.
• D. Creepage distance is the distance through the earth; clearance is the distance along the pole.

Answer: (A)

Creepage distance is the path along the surface of the insulator between two conductors, while clearance distance is the shortest straight-line distance through air between those conductors. The surface path matters because contaminants, moisture, and surface leakage can allow current to travel along the insulator, so the creepage length is the effective route that must resist tracking and surface flashover. The straight-line air gap matters because arcing or breakdown through air occurs along the direct path, independent of surface conditions, so clearance is about the air path.

Thus the statement that creepage distance is the surface path length along the insulator and clearance is the shortest straight-line distance through air between conductors is the correct distinction. The other options mix up these concepts (swapping surface path with straight-line air gap, or referencing paths around or through the insulator, or through the earth/along a pole) and don’t reflect the standard definitions.