Journeyman Electrician Exam (NEC)Wiring Methods and MaterialsMedium
A commercial electrician is installing a new 480-volt, 3-phase motor feeder in a wet location. The feeder consists of three 3/0 AWG THW copper conductors and one 6 AWG copper equipment grounding conductor. What is the minimum radius for a conduit bend if using 2-inch Rigid Metal Conduit (RMC)?
- A18 inches
- B6 inches
- C12 inches
- D10 inches
Show answer & explanationAnswer & explanation
Correct answer: D. 10 inches
According to NEC Table 2, Chapter 9, for a 2-inch RMC, the minimum radius of the inner edge of any bend is 10 inches. This ensures conductors are not damaged during installation and can be easily pulled.
Why the other options are wrong
- A. 18 inches is excessively large and not the minimum required.
- B. 6 inches is too small for 2-inch RMC.
- C. 12 inches is larger than required but acceptable; however, 10 inches is the minimum.
Conduit Bend Radius
The minimum allowed radius for a conduit bend, specified in the NEC to prevent damage to conductors during installation and to facilitate wire pulling.
- Minimum bend radii vary by conduit type and size.
- Ensures conductors are not damaged during installation.
- Found in NEC Chapter 9, Table 2.
Memory trick: Bends prevent kinks, check the chart, don't be a sharp-corner smarty.