What is the purpose of connecting normally non-current-carrying conductive materials to earth?

Connecting normally non-current-carrying conductive materials to earth serves primarily to limit the voltage to ground on these materials. This is crucial for safety reasons; by grounding, these conductive elements help ensure that they do not accumulate any voltage that could potentially pose a shock hazard. Grounding these materials effectively provides a path for fault currents and prevents dangerous voltage levels from developing during abnormal conditions, such as insulation failures or lightning strikes.

This practice is an essential element of grounding and bonding systems, which aim to protect both people and equipment from electrical faults. While the other options may suggest benefits related to cost, performance, or construction techniques, they do not address the fundamental safety purpose of grounding non-current-carrying conductive materials, which is vital in any electrical installation.