UL 458:2006 pdf download.Power Converters/Inverters and Power Converter/lnverter Systems for Land Vehicles and Marine Crafts.
8.3 Serviceman servicing
8.3.1 An electrical component that may require adjustment, servicing, or maintenance not specified in theoperator's manual shall be located and mounted with respect to other components and with respect togrounded metal parts so that it is accessible for electrical service functions without subjecting theserviceman to the likelihood of electric shock or injury to persons，Access to components for servicingshall not be impeded by other components or by wiring in the direction of access.
8.3.2 The electrical components mentioned in 8.3.1 include a fuse and an adjustable control.
8.3.3 All conductive internal parts that are accessible to service personnel and that are usually expectedto be at ground potential(heatsinks and the like), but are energized and involve a risk of electric shock,shall be marked in accordance with 57.22.
Assembly
9.1 An uninsulated live part shall be secured to the base or surface so that it will be prevented fromrotating or shifting in position as the result of normal stresses if such movement might result in a reductionof spacings below the minimum acceptable values.See Section 28,Spacings.
9.2 A component such as a rectifier element, control switch, lampholder, attachment plug receptacle, orplug connector shall be mounted securely and shall be prevented from turning by means other thanfriction between surfaces.
