SAFE APPLICATION OF TOTALLY ENCLOSED MOTORS IN HAZARDOUS CLASS-I, DIVISION-2 LOCATIONS

It is common practice in the petrochemical industry to use nonlabeled totally enclosed motors rated 500 hp and below in Class I, Division 2 hazardous locations. Such motor applications meet the requirements of the National Electrical Code, and have proven over time to be safe. Th e Fine Print Note, [FPN] No. 1, in Article 501-8(b) of the NEC caution s users ''to consider the temperature of internal and external surface s which may be exposed to the flammable atmosphere'' before applying t he motor. The code in Section 501-8(b) does not differentiate between open and totally enclosed motors. This paper will discuss the role of motor internal as well as external surface temperature in determining if totally enclosed motors are safe for use in Class I, Division 2 loc ations. The implications of using adustable speed drives with TE motor s will be discussed. Recommendations are proposed for changes to the N EC, user application criteria, and additional nameplate information to be provided by the motor manufacturer.