Spark Protected : Electrical equipment enclosed in a tight case or protected by shields, screens, or insulation that contains sparks or prevents their emission
NFPA 37 Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines, 2002 ed. http://pozhproekt.ru/nsis/nfpa/NFPA37-2002.pdf, (Std: Install and Use of Stnry Combustion Engines and Gas Turbines - Amer) {201 NFC}