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Friday, February 24, 2023

Question:

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

A

Answer:

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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