When using a trench box, trench width should be ___________ greater than the outside diameter of the pipe.

• A. 1-2 Feet
• B. 6 Inches
• C. 3-4 Feet
• D. Equal to Outside Diameter

Answer: (A)

The main idea here is ensuring enough room around the pipe for safe installation and work inside a trench with a trench box. You want extra space so you can position the trench box, place supports, and maneuver tools without the box or soil pressing on the pipe. Making the trench width about one to two feet greater than the outside diameter of the pipe gives that needed clearance on both sides, helps prevent contact with the pipe, and provides room for backfilling as work progresses. If the trench were only the same width as the pipe, there’d be no room for the box or for workers to operate safely. If it were much wider, like 3-4 feet more, that would be unnecessarily large and not typically required for safe setup. So the recommended clearance is about 1-2 feet wider than the pipe’s outside diameter.