How does the NEC define "ordinary" locations?

The National Electrical Code (NEC) defines "ordinary" locations as those where flammable or explosive materials are not expected to be present under normal operating conditions. This means that in such areas, the risk of ignition from electrical equipment is minimal, which allows for the use of standard equipment and wiring methods without additional protective measures.

In ordinary locations, the environment is considered stable and predictable, making it suitable for conventional installations without the need for specialized designs or equipment that would be necessary in hazardous locations. This definition helps engineers, electricians, and safety professionals categorize locations accurately to ensure safety and compliance with electrical codes.

The other options describe conditions or environments that either require special attention due to the presence of potential hazards (like explosives or flammable materials) or do not fit the criteria of an “ordinary” location, like high humidity or environments requiring additional training or equipment safety protocols.