503.125 Motors and Generators — Class III, Divisions 1 and 2
Exception: In locations where, in the judgment of the authority having jurisdiction, only moderate accumulations of lint or flyings are likely to collect on, in, or in the vicinity of a rotating electrical machine and where such machine is readily accessible for routine cleaning and maintenance, one of the following shall be permitted:
- Self-cleaning textile motors of the squirrel-cage type.
- Standard open-type machines without sliding contacts, centrifugal or other types of switching mechanisms, including motor overload devices
- Standard open-type machines having such contacts, switching mechanisms, or resistance devices enclosed within tight housings without ventilating or other openings