Section 129.320 - Generators and motors(a) Each generator and motor, except a submersible-pump motor, must be- (1) In an accessible space, adequately ventilated and as dry as practicable; and(2) Mounted above the bilges to avoid damage by splash and to avoid contact with low-lying vapors.(b) Each generator and motor must be designed for an ambient temperature of 50 °C (122 °F), except that- (1) If the ambient temperature, in the space where a generator or motor is, does not exceed 40 °C (104 °F) under normal operating conditions, the generator or motor may be designed for an ambient temperature of 40 °C (104 °F); and(2) A generator or motor designed for an ambient temperature of 40 °C (104 °F) may be used in a location where the ambient temperature is 50 °C (122 °F), if the generator or motor is derated to 80 percent of the full-load rating and if the rating or setting of the overcurrent devices of the generator or motor is reduced accordingly.(c) For each generator rated at 50 volts or more, a voltmeter and an ammeter used for measuring voltage and current while the generator is in operation must be provided. For each alternating-current generator, a means for measuring frequency must also be provided. To ensure satisfactory operation of each generator, additional control equipment and measuring instruments, if needed, must also be provided.(d) Each generator must have a nameplate attached to it indicating- (1) Name of manufacturer, type of generator, and designation of frame;(2) Output in kilowatts, or horsepower rating;(3) Kind of rating (continuous, overload, or other);(4) Amperes at rated load, voltage, and frequency;(5) Number of phases, if applicable;(6) Type of windings, if DC;(7) When intended for connection in a normally grounded configuration, the grounding polarity; and(8) For a generator derated to comply with paragraph (b)(2) of this section, the derated capacity.(e) Each motor must have attached to it a nameplate containing the information required by Article 430 of NFPA 70.