To determine whether the statement is true or false, let’s examine the principle and regulations related to the ampacity ratings of Type NM cable.
- 90°C Conductor Ampacity Rating: Type NM cable conductors are typically rated for 90°C. This rating can be used for ampacity adjustment and correction calculations.
- Final Ampacity Limitation: According to NEC (National Electrical Code) regulations, the final calculated ampacity after adjustments and corrections must not exceed the ampacity of the conductor based on a 60°C rating.
Let's break this down step-by-step:
1. Ampacity Rating Usage:
- When you have Type NM cable with conductors rated at 90°C, you can initially use the 90°C ampacity values for adjustment and correction calculations. This means you can use these values to start with before doing any adjustments for factors such as temperature, number of conductors, etc.
2. Final Computed Ampacity Compliance:
- After making necessary adjustments and corrections using the 90°C rated values, the NEC requires that the final ampacity value must not exceed what is allowed for a 60°C rated conductor. This ensures safety and compliance with the code requirements.
Considering these points, the correct understanding is:
The 90°C conductor ampacity rating is permitted to be used for ampacity adjustment and correction calculations, provided that the final calculated ampacity does not exceed that for a 60°C-rated conductor.
Thus, the statement given in the question is True.
So, the answer is:
a. True
