COMPUTER/DATA PROCESSING EQUIPMENT 70-671

640-11. Amplifiers and Rectifiers - Type. (a) Approved Type. Amplifiers and rectifiers shall be of an approved type and shall be suitably housed. (b) Readily Accessible. Amplifiers and rectifiers shall be so located as to be readily accessible. (c) Ventilation. Amplifiers and rectifiers shall be so located as to provide sufficient ventilation to prevent undue temperature rise within the housing. 640-12. Hazardous (Classified) Locations. Equipment used in hazardous (classified) locations shall comply with Article 500. 640-13. Protection Against Physical Damage. Amplifiers, rectifiers, loudspeakers, and other equipment shall be so located or protected as to guard against physical damage, such as might result in fire or personal hazard.