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Reference Standard for Double Insulation Systems for Use in Electronic Equipment

UL 2097

1.1 Scope

1.1.1 These requirements cover double insulation systems intended for use in ungrounded electronic equipment marked "Double Insulation," "Double Insulated," or with the double-insulation symbol intended to be employed in accordance with the National Electrical Code, ANSI/NFPA 70.

1.1.2 These requirements also cover:

a) Equipment required by the end-product standard to be provided with a double insulation system and to be grounded and

b) Double-insulated equipment permitted by the end-product standard to be provided with a non-functional means for grounding.

1.1.3 Equipment marked "Double Insulation," "Double Insulated," or with the double-insulation symbol shall comply with the applicable requirements in this standard and in the standard covering the particular type of equipment - the end-product standard. In cases where the end-product standard contains requirements for double insulation, the end-product standard takes precedence. It is intended that the requirements in this standard be applied to end products marked as described unless the end-product standard specifies different requirements.

1.1.4 These requirements were developed for categories that do not have double insulation requirements, to provide guidance about double insulation systems, and to promote consistent approaches to double insulation. Double insulation requirements for electronic equipment are applicable to the double insulation systems used in products contained in various end-product, component and systems standards. Guidelines and Applications for Double Insulation Systems for Electronic Equipment in Appendix A covers:

a) Level of Protection Provided by Double Insulation,

b) Methods to Address Product-Specific Double Insulation Requirements, and

c) Guidelines for Including Double Insulation Requirements in an End-Product Standard.

1.1.5 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of fire, electric shock, or injury to persons shall be evaluated using the appropriate additional component and end-product requirements to determine that the level of safety as originally anticipated by the intent of this standard is maintained. A product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this standard shall not be judged to comply with this standard. Where appropriate, revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.