The smallest size conduit allowed to enclose motor terminals from a junction box is which size?

• A. 1/2 inch
• B. 1 inch
• C. 1 1/2 inch
• D. 3/8 inch

Answer: (D)

The main idea here is that conduit size is driven by physical space for the motor’s terminal connections. When conductors are brought from a junction box into a motor’s terminal box, the entry conduit must be large enough to pass the conductors and still leave room to reach and tighten the terminal screws or lugs inside the motor’s box. For a simple setup, the smallest standard size that accommodates those connections is 3/8 inch. Using any smaller size would crowd the conductors and hardware, making it difficult or unsafe to terminate properly. Larger sizes are allowed if the situation needs more conductors or larger terminal hardware, but the question asks for the minimum required size, which is 3/8 inch.