What lug temperature rating is specified for the lugs in the described circuits?

What lug temperature rating is specified for the lugs in the described circuits?

• A. 60°C
• B. 75°C
• C. 90°C
• D. 105°C

Answer: (B)

Lug temperature rating tells you the maximum temperature the lug termination can safely handle without degrading the insulation or the connection. When selecting lugs, you want a rating that matches the insulation rating of the conductors and the expected operating temperatures. In many standard circuits, the lugs are specified at 75°C, which is a common safe default that covers typical conductor insulation like THHN/THWN-2 for many installations. A rating of 60°C would be too low for modern conductors, while 90°C or 105°C lugs are used only if the conductors and equipment are explicitly rated for those higher temperatures and the installation calls for it. Since the described circuits specify lugs rated at 75°C, that is the appropriate choice.

Lug temperature rating tells you the maximum temperature the lug termination can safely handle without degrading the insulation or the connection. When selecting lugs, you want a rating that matches the insulation rating of the conductors and the expected operating temperatures. In many standard circuits, the lugs are specified at 75°C, which is a common safe default that covers typical conductor insulation like THHN/THWN-2 for many installations. A rating of 60°C would be too low for modern conductors, while 90°C or 105°C lugs are used only if the conductors and equipment are explicitly rated for those higher temperatures and the installation calls for it. Since the described circuits specify lugs rated at 75°C, that is the appropriate choice.