These requirements cover component electronic controls intended to be factory installed on or in appliances and other utilization equipment rated 600 V or less@ used in ordinary dry locations as defined in the National Electrical Code@ NFPA 70@ and that comply with the requirements for such appliances and equipment.For a control covered by this standard@ it is assumed that:a) No voltage greater than 600 V above ground will be present in a control@b) An isolation transformer@ if provided@ will generally furnish power at a lower potential than the primary voltage@ andc) The output of the control will not be located in a circuit operating at greater than 600 V above ground in the end-use product.If conditions other than these are provided@ consideration shall be given to the need for additional requirements.A control covered by this standard is a single device or a series of separate components with interconnecting wiring employing one or more input power and possibly signal ports@ solid-state circuitry@ and one or more output switching components to directly control all or a portion of the end-use product load. Included are controls that respond directly or indirectly to changes in temperature@ humidity@ or pressure to affect operation of an appliance@ function as an electronic timer@ or electronically store or process information by virtue of a memory system.These requirements cover controls intended for connection only to a low-voltage circuit of limited power supplied by a primary battery or by a Class 2 transformer@ where a failure of such a control would result a risk of fire@ electric shock@ or injury to persons in the end-use product.These requirements do not cover a control intended for installation in or on refrigeration or air conditioning equipment that is used in industrial applications or in hazardous locations as defined in the National Electrical Code@ NFPA 70. Such equipment is covered in the Standard for Temperature-Indicating and -Regulating Equipment@ UL 873.These requirements do not cover controls for use where exposed to oil@ grease vapors@ lint@ other contaminants@ or high humidity in the end application.These requirements address the potential risks unique to the electronic nature of a control. Equipment or components employing an electronic feature shall also comply with the basic requirements contained in the applicable end-product or component standard. These requirements are intended to supplement applicable end-product or component standards and are not intended to serve as the sole basis for investigating all risks associated with a control. For example@ requirements for the means of enclosing live parts@ mechanical assembly of components@ corrosion protection@ use of polymeric materials@ evaluation of internal wiring and connections within the control@ calibration@ and similar requirements@ are not included in this standard.