The "600V/1000V" marking commonly found on electrical cables does not indicate that the cable is suitable for both voltages simultaneously. Instead, it specifies the cable's rated voltage for different types of grounding systems. In simpler terms, the 600V rating means that in a grounded system, the voltage between any conductor and ground must not exceed 600V. The 1000V rating indicates that in an ungrounded system, the voltage between any two conductors must not exceed 1000V.

This dual voltage rating provides clearer safety guidance, helping engineers select the appropriate cable based on their specific power system configuration. In grounded systems, where there is a direct connection to earth, the voltage between conductors and ground is typically lower, hence the lower rating. In ungrounded systems, however, the potential voltage difference between conductors can be higher, necessitating the higher voltage rating.

When selecting cables, it is crucial to consider the grounding conditions of the actual application environment and refer to relevant electrical codes. This ensures the cable's rated voltage meets the system's safety requirements and prevents potential hazards caused by excessive voltage.

Beyond voltage ratings, other factors must be considered for proper cable usage, including ambient temperature and installation methods. These variables can significantly impact a cable's current-carrying capacity and service life. Therefore, a comprehensive evaluation of all relevant factors is essential to ensure safe and reliable cable operation.