The Type 1 electrical cabinet is the baseline electrical cabinet for both UL and NEMA. All other electrical cabinets are based on this model, but add extra layers of protection and complexity.
The Type 1 electrical cabinet offers basic protection from personnel coming into contact with the electrical components inclosed. The only environmental protection the Type 1 provides is from falling dust. The Type 1 electrical cabinet is the most basic electrical cabinet and is for indoor use only.
Type 1 Electrical Cabinet NEMA vs UL
NEMA
Indoor use provides a protected measure to prevent personal contact with dangerous components. It also protects internal components from external materials such as dirt.
UL
Indoor use offers protection against personal contact with internal components and a measure to protect internal components from access by external materials such as dirt.