What is the RECOMMENDED bend radius of a conduit with an internal diameter of 51 mm (2 in)?

The correct answer is D. 508 mm (20 in). Option D (508 mm / 20 in) is correct because the recommended bend radius for conduit is 10 times the internal diameter: 51 mm × 10 = 510 mm, which rounds to 508 mm (20 in). This generous radius prevents conductor insulation damage, reduces pulling tension, and maintains conduit…

Pathways and Spaces

Question

Options

A203 mm (8 in)
B305 mm (12 in)
C406 mm (16 in)
D508 mm (20 in)

How the community answered

(33 responses)

A
3% (1)
B
6% (2)
C
9% (3)
D
82% (27)

Explanation

Option D (508 mm / 20 in) is correct because the recommended bend radius for conduit is 10 times the internal diameter: 51 mm × 10 = 510 mm, which rounds to 508 mm (20 in). This generous radius prevents conductor insulation damage, reduces pulling tension, and maintains conduit structural integrity during and after bending.

Options A (203 mm), B (305 mm), and C (406 mm) correspond roughly to 4×, 6×, and 8× the internal diameter respectively - these are too tight, would stress the conductors, risk conduit deformation, and are below the recommended standard for a 51 mm conduit.

Memory tip: "Ten times to bend it fine" - multiply the internal diameter by 10 to get the recommended bend radius. For a 2-inch (51 mm) conduit, that gives you 20 inches (508 mm), making D the clear choice.

Topics

#conduit bend radius#industry standards#pathway design#cable routing

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