UL 2557:2020 free download

UL 2557:2020 free download Membrane Switches
1 Scope
1.1 These requirements apply to membrane switches actuated by human activity, via a membrane orsensing substrate,to operate or control appliances and electrical equipment. The membrane switchelectrical rating not to exceed 30 Vrms and power not greater than 100 VA.
1.2When this standard references “switches” it shall mean “membrane switches”unless specificallyindicated.
1.3Membrane switches which incorporate additional control functions governed by the switch functionare within the scope of these requirements. Additional control functions shall be evaluated for theirsuitability using the applicable standards for the application.
1.4 These membrane switches are intended to be operated by a person, via a membrane or by actuatinga sensing substrate.
1.5 These requirements cover the indirect actuation of the switch when the operation of the actuatingmember or sensing unit is provided by a remote control or a part of an appliance or equipment such as adoor.
1.6 Embedded components are evaluated with regards to their safety and application to the membraneswitch construction.The acceptability of an embedded component in the membrane switch shall beconsidered with regards to construction and performance requirements in the end product finalapplication.
Components
2.1 Except as indicated in this section, a component of a product covered by this standard shall complywith the requirements for that component.
2.2A component is not required to comply with a specific requirement that:
a) Involves a feature or characteristic not required in the application of the component in theproduct covered by this standard, or
b) ls superseded by a requirement in this standard.
2.3 A component shall be used in accordance with its rating established for the intended conditions ofuse.
2.4Specific components are incomplete in construction features or restricted in performancecapabilities. Such components are intended for use only under limited conditions，such as certaintemperatures not exceeding specified limits, and shall be used only under those specific conditions.
3 Units of Measurement
3.1Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.
4 References
4.1 Undated references
4.1.1 Any undated reference to a code or standard appearing in the requirements of the standard shall be interpreted as referring to the latest edition of that code or standard.
4.2 Normative references
4.2.1 The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of the standard.
4.2.2 The following are ASTM test procedures referenced:
a) Standard Test Methods for DC Resistance or Conductance of Insulating Materials, ASTM D257
b) Standard Test Methods for Thickness of Solid Electrical Insulation, ASTM D374
c) Standard Test Method for Pressure-Sensitive Adhesive-Coated Tapes Used for Electrical and Electronic Applications, ASTM D1000