National Electrical Installation Standards

Standards as High as Your Own

Friday, February 24, 2023


Dear CQD, are expansion fittings required for Rigid Metal Conduit installed for the branch circuits and feeders in a parking garage? Best, Nate Hilfiger



Hi Nate, most likely yes, an expansion fitting(s) would be required in a parking garage for Rigid Metal Conduit (RMC).

  • Section 300.4(H) requires a listed expansion/deflection fitting to be used when a raceway crosses a structural joint intended for expansion, contraction, or deflection, used in buildings, bridges, parking garages, or other structures.


  • Section 300.7(B) requires Expansion, Expansion-Deflection, and Deflection Fittings for raceways exposed to different temperatures. The 3rd sentence in Informational Note 1. of Section 300.7(B) provides the calculation for determining the expansion/deflection for Rigid Metallic Conduit. Allow for 0.0000065 inches of expansion/deflection for every inch of conduit, per degree Fahrenheit of temperature change.

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