IEEE recommended practice for the testing, design, installation,and maintenance of electrical resistance heat tracing for commercialapplications

Specific test requirements for qualifying electrical resistance heating cables for commercial service and a basis for electrical and thermal design are provided. Heater characteristics are addressed, and installation and maintenance requirements are detailed. Recommendations and requirements for unclassified heating cable applications are provided     

Less-flammable liquids used in transformers

Two main types of replacement liquid have been developed, high molecular-weight hydrocarbons and polydimethylsiloxane (silicone). These liquids are formulated to withstand fairly large amounts of electrical arcing, and are less flammable than mineral oils. These properties qualify the liquids for use in installations where less-flammable liquids are required and where the use restrictions associated with the products are followed. The requirements of the National Electrical Code are described and the advantages of using less-flammable liquids are also described. The fault mechanisms of transformers are discussed. The UL investigation of transformer liquids and the limitations of use are also discussed