Journeyman Electrician Exam (NEC)Wiring Methods and MaterialsHard
A commercial electrician is installing a new 480-volt, 3-phase motor feeder in a wet location. The feeder consists of 3-inch rigid metal conduit (RMC). What is the minimum radius for a field bend in this RMC, assuming it does not contain lead-sheathed cables?
- A18 inches
- B24 inches
- C21 inches
- D15 inches
Show answer & explanationAnswer & explanation
Correct answer: A. 18 inches
According to NEC Table 2, Minimum Bending Radii for Conduit and Tubing, for a 3-inch rigid metal conduit (RMC) that does not contain lead-sheathed cables, the minimum radius of the curve for a field bend is 18 inches.
Why the other options are wrong
- B. This significantly exceeds the minimum required radius, which is permissible but not the minimum.
- C. This exceeds the minimum required radius, which is permissible but not the minimum.
- D. This is less than the minimum required bending radius for 3-inch RMC.
RMC Bend Radius (Field Bend)
The smallest allowable radius for a field-made bend in rigid metal conduit (RMC) to prevent conductor damage and facilitate pulling.
- Varies with conduit size.
- Prevents insulation damage and kinking.
- Specified in NEC Table 2.
Memory trick: RMC's bend, by the table you'll tend.