What is the maximum voltage rating for THHN and THWN conductors?

The maximum voltage rating for THHN (Thermoplastic High Heat-resistant Nylon-coated) and THWN (Thermoplastic Water-resistant Nylon-coated) conductors is 600 volts. This rating is vital for ensuring that these types of conductors can safely carry electrical current without the risk of insulation breakdown or other hazards that could arise with higher voltages. Conductors rated for 600 volts are commonly used in residential, commercial, and industrial applications, making them versatile and suitable for a wide variety of wiring situations.

It's essential for electricians and professionals to understand this rating to select the appropriate type of wire for specific applications and ensure compliance with national electrical codes and safety standards. Using conductors beyond their rated voltage can lead to insulation failure, resulting in short circuits, electrical fires, or other dangerous situations.