Conduits Sizes

Electrical conduits trade sizes and max distance between supports

Conduit Trade Size
(in)
Inside DiameterMax Distance Between Supports
Rigid Metal (PVC)
(ft)
(inches)(mm)
1/2 0.622 15.8 10 (3)
3/4 0.824 20.9 10 (3)
1 1.049 26.6 12 (3)
1 1/4 1.380 35 14 (5)
1 1/2 1.610 40.9 14 (5)
2 2.067 52.5 16 (5)
2 1/2 2.469 62.7 16 (6)
3 3.068 77.9 20 (6)
3 1/2 3.548 90.1 20 (7)
4 4.026 102.3 20 (7)
5 5.047 128.2 20 (7)
6 6.093 154.8 20 (8)

According "National Electric Code (US NEC or NFPA 70) Section 344 for Rigid Metal Conduit":

  • a conduit must be supported at intervals no longer than 3 m (10 ft) and fastened not more than 0.9 m (3 ft) from a box, fitting, etc.
  • the distance between supports for straight runs of conduit shall be permitted in accordance to the table above provided the conduit is made up with threaded couplings and such supports prevent transmission of stresses to termination where conduit is deflected between supports

Related Topics

  • Electrical - Electrical units, amps and electrical wiring, wire gauge and AWG, electrical formulas and motors

Related Documents

Tag Search

Need some Expert Advice?

JustAnswer can help you! Talk with a verified expert until your satisfied, 100% money- back guarantee.

Search the Engineering ToolBox

- "Search is the most efficient way to navigate the Engineering ToolBox!"

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your SketchUp model with the Engineering ToolBox - SketchUp Extension/Plugin - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Translate the Engineering ToolBox!
About the Engineering ToolBox!

close