Which of these is pulled through a raceway to test for obstructions before a cable pull?

• A. Duct rodder
• B. Fish tape
• C. Mandrel
• D. Conduit reamer

Answer: (C)

Testing a raceway for obstructions before pulling a cable is done with a conduit mandrel. A mandrel is a sized plug or flexible tester that you pull through the interior of the conduit to feel for tight spots, burrs, sharp bends, or debris that could snag the cable. If the mandrel passes smoothly, the path is clear for the pull; if it catches, you address the obstruction before attempting the cable run. A duct rodder is used to push or pull a line through a duct but isn’t specifically a clearance check, fish tape is mainly for fishing wires or paths and not for testing interior passages, and a conduit reamer smooths the inside rather than testing for obstructions.