In a straight exposed rigid PVC conduit run between securely mounted terminations, ABB/Carlon’s expansion guidance calls for an expansion fitting at what calculated length change?
- A1/8 inch or more
- 1/4 inch or more
- C1/2 inch or more
- D1 inch or more
Where to look it up
https://library.e.abb.com/public/f6fc49142da042dc9d86051b8f55303e/ABB_Carlon_PVC%20Elbows%20and%20fittings_catalog_ENG_US_7TKK000122.pdf
Why B is correct
The cited guidance uses 1/4 inch or greater. Determine expected movement from conduit length and temperature range, then set and support the fitting according to its installation instructions. The threshold is not a guarantee that a particular movement will cause mechanical failure. Source: https://library.e.abb.com/public/f6fc49142da042dc9d86051b8f55303e/ABB_Carlon_PVC%20Elbows%20and%20fittings_catalog_ENG_US_7TKK000122.pdf