UL 372:2007 pdf download.Automatic Electrical Controls for Household and Similar Use - Part 2: Particular Requirements for Burner lgnition Systems and Components.
8.4A.1 Paragraph 8.4A.2 is intended to provide a reasonable degree of protection to aserviceman performing a mechanical function on energized equipment.Such a servicefunction does not in itself cause exposure to live parts or moving parts capable of causinginjury to persons but it is commonly necessary to perform the function with the equipmentenergized.
8.4A.2 A live part or a moving part capable of causing injury to persons shall be located,guarded, or enclosed so as to reduce the risk of unintentional contact by a servicemanadjusting or resetting a control, or performing a mechanical service function that may haveto be performed with equipment energized. (See cC.7A).
These requirements do not apply to a mechanical service function that is not normallyperformed with equipment energized.
8.4A.3 Mechanical service functions that may have to be performed with equipmentenergized include adjusting the setting of a temperature or pressure control; resetting acontrol trip mechanism; or operating a manual switch. A control that has the set pointsealed at the factory as described in 11.3.4 and that does not have marking or instructionsfor adjustment, is not considered to be adjustable.
8.4A.4 An adjustable or resettable electrical control or manual-switching device may belocated or oriented with respect to live parts so that manipulation of the mechanism foradjustment, resetting, or operation can be accomplished in the normal direction of accessif live parts are not located in front (in direction of access) of the mechanism, and near anyside or behind the mechanism, unless guarded.
