Master Electrician Practice Exam

In conductor markings, what does the "-2" in RHW-2 signify?

1. Maximum operating temperature of 75 degrees C

2. Maximum operating temperature of 90 degrees C

3. Maximum operating temperature of 105 degrees C

4. Maximum operating temperature of 120 degrees C

The correct answer is: Maximum operating temperature of 90 degrees C

The marking "-2" in RHW-2 indicates a maximum operating temperature of 90 degrees Celsius. Understanding conductor markings is essential, as these specifications directly impact the safety and functionality of electrical installations. The designation "RHW" refers to the type of insulation used on the conductor, which is designed to be resistant to moisture and suitable for wet locations. The suffix "-2" specifically denotes the thermal rating of that insulation, which in this case specifies a maximum temperature threshold of 90 degrees Celsius. This is particularly important when determining the application of the wire in various environments and ensuring compliance with the National Electrical Code (NEC) standards and safety regulations. Conductor temperature ratings are crucial for preventing overheating and potential fire hazards, making the correct identification of these markings vital for electrical professionals.