Do the rules for spacing from decking apply equally to rigid metal conduit and intermediate metal conduit when installed under metal-corrugated sheet roof decking?

When considering the installation of rigid metal conduit (RMC) and intermediate metal conduit (IMC) under metal-corrugated sheet roof decking, it is important to understand the different requirements for spacing and the nature of each type of conduit. The correct answer is based on the distinct characteristics and installation guidelines associated with these two types of conduits.

RMC and IMC have different physical properties and may have variations in their allowable spacing due to the way they are designed to handle environmental and physical stresses. Intermediate metal conduit is typically lighter and used in applications where less mechanical protection is necessary, while rigid metal conduit is more robust and provides enhanced protection for cables and conductors.

When installed in specific locations, such as under roof decking, the rules governing their installation in terms of spacing can vary to account for these differences. This is particularly significant in preventing potential mechanical damage, moisture penetration, or other environmental factors that might affect the performance and safety of the electrical system.

The answer provided highlights that the spacing rules do not apply equally to both conduit types under those conditions, which ensures compliance with safety standards and best practices in electrical installations. This differentiation is crucial for maintaining the integrity of the conduit and ensuring a safe wiring system.