Where is Electrical Metallic Tubing (EMT) prohibited from being installed, according to WAC?

Electrical Metallic Tubing (EMT) is prohibited from being installed in direct contact with the earth due to its susceptibility to moisture and soil corrosiveness, which can lead to deterioration and compromise the integrity of the conduit over time. This restriction ensures that the electrical systems remain safe and effective, as EMT is designed primarily for use above ground where it can provide mechanical protection without the risks associated with underground installations.

The other options do not accurately reflect the conditions under which EMT is restricted. EMT can be used in dry locations and above ground structures but is not suitable for direct earth contact. Similarly, EMT can be installed in locations with ground-type attachment plugs, as long as it adheres to other applicable electrical codes and guidelines.