Insulation for underground service conductors must have a voltage rating not less than what?

Insulation for underground service conductors must have a voltage rating that is not less than the applied voltage to ensure safe operation under normal conditions. When conductors are installed underground, they are exposed to various factors such as moisture and potential physical impacts, which can affect their integrity. Having insulation rated at least to the level of the applied voltage provides a sufficient safety buffer against electrical breakdown, events such as short circuits, or failure due to environmental conditions.

Insulating these conductors to the applied voltage also aligns with industry standards and electrical codes, which require materials to handle the maximum voltage that they will be subjected to during operation. This ensures that the risk of insulation failure and the subsequent hazards of electrical shock or fire are minimized. By adhering to this standard, safety and reliability of electrical installations are maintained.

In contrast, other voltage ratings such as 150%, 200%, or 300% of the applied voltage are not typically required specifically for underground service conductors in standard practice. These higher ratings may apply in more specific scenarios or special equipment but are not the general requirement in this context.