If the junction cannot be made by a manhole, which installation is used to connect large trunk sewers?

If the junction cannot be made by a manhole, which installation is used to connect large trunk sewers?

• A. Catch Basin
• B. Cleanouts
• C. Air Test
• D. Junction boxes

Answer: (D)

When you can’t fit a manhole to join large trunk sewers, a junction box is used. This installation provides a large, accessible chamber where big-diameter pipes can be connected or spliced without building a full manhole at that spot. It also allows maintenance access and future work just like a manhole would, but in a form that suits the size and location of the trunk lines. Catch basins are surface inlets for stormwater and debris, not for joining large sewer lines. Cleanouts are small vertical access points for cleaning a line, not for linking large trunks. An air test is a method to check for leaks, not a way to connect pipes. So the junction box is the appropriate choice for this situation.