Voltage Rating

Voltage rating for cables varies between standards. Typical voltage ratings for cables are 300V and 600V.

CE requires the equipment or other installations to have insulation rating equal to the maximum circuit voltage applied to any conductor within the cable or raceway.

For North America Industrial, machines require 600 volt-rated wire as described in NFPA 79 section 15. Examples of industrial machines, machine tools (metal cutting and forming machines), plastics machinery, wood machinery, assembly machines, material handling machines, inspection machines, and testing machines. The recommended standard is 600V for power wiring (motor interconnect) and 600V for control (feedback device interconnect) on 230 to 480VAC systems.

In most cables, there are at least two insulation devices in the construction: a conductor insulator and an outer jacket. The specified voltage rating is defined in relation to the conductor and an adjacent item. For example, the single conductor has the insulation rated between itself and any other device (shield or other device capable of developing a voltage potential) and the outer jacket has no insulation rating recognizable by UL and therefore cannot be considered as a factor in the rating. According to UL, it is just a protective and binding element.

Special requirement for DC bus link and external brake resistors is a voltage rating of 1000V.