What is the maximum temperature rating for non-metallic sheathed cable ampacity?

The maximum temperature rating for non-metallic sheathed cable ampacity is 90°C. Non-metallic sheathed cable, often referred to as NM cable, has a thermal limit that allows it to operate safely at temperatures up to this level. The 90°C rating is crucial when considering the ampacity or current-carrying capacity of the cable; it ensures that the cable can handle the electrical load without overheating or risking damage.

Wire insulation materials are selected specifically for their ability to withstand high temperatures while maintaining their structural integrity and electrical performance. The 90°C rating allows for a greater flexibility in installation and use, particularly in scenarios where higher ambient temperatures might be encountered, or in applications needing to draw more current.

Understanding these ratings is vital for safe and efficient electrical installations, as improper usage of cables rated for lower temperatures could lead to insulation failure and potential fire hazards.