Power sources for mixing plants

(a) All electrical switches, controls, motors, and lights, if located in the mixing rooms shall conform to the requirements of Class II, Division 2 of the National Electrical Code; otherwise they should be located outside the mixing room. The frame of the mixer and all other equipment that may be used shall be electrically bonded and provided with a continuous path to the ground. (b) All internal-combustion engines used for electric power generation shall be located outside the mixing plant building, or shall be properly ventilated and isolated by a fire wall. The exhaust systems on all such engines shall be located so any spark emission can not be a hazard to any materials in or adjacent to the plant.