19 Feb 2018

Tape MeasureWhen selecting the conduit size for your project, it’s important to consider the following variables:

  1. Number of conductors
  2. Size of the conductors
  3. Type of conduit

Having too many conductors packed into a conduit system can result in damage during the pulling process. Furthermore, because different types of conductors offer a varied thickness of insulation, it’s important to determine the cross-sectional area of each conductor used. Without an adequate amount of space between the conductors and the conduit wall, they are at risk for overheating. These issues can be avoided by adhering to the requirements for minimum raceway size found in Chapter 9 of the NEC.

Note: Stainless steel is not listed in Chapter 9 of the NEC as one of the various types of raceway. The requirements for rigid stainless steel conduit will be consistent with that of RMC (see below). Similarly, the requirements for stainless EMT will be consistent with that of ordinary EMT.

Electrical Metal Tubing Article 358 Rigid Metal Conduit Article 344

Conduit Size