The length of threading on an EMT box connector is approximately 7/16 inch. The locknut is 1/8 inch thick and the metal of the box is 1/32 inch thick. Once installed, how much thread is left for a threaded bushing?

• A. 7/32 inches
• B. 9/32 inches
• C. 11/32 inches
• D. 5/16 inches

Answer: (B)

The amount of thread left for the bushing is found by subtracting the portions of thread that are taken up by the locknut and the box metal from the total threaded length.

Total threaded length: 7/16 inch.

Subtract the locknut thickness: 1/8 inch.

Subtract the box metal thickness: 1/32 inch.

Convert to a common denominator (32): 7/16 = 14/32, 1/8 = 4/32, 1/32 = 1/32. The used portion is 4/32 + 1/32 = 5/32. Subtract: 14/32 − 5/32 = 9/32.

So, 9/32 inch of thread remains for the threaded bushing.