Surge Background
Surges occur on the AC power mains as a result of switching operations in the power grid and from nearby lightning strikes, either directly to the power distribution system or to nearby ground. Radiated coupling of surges into I/O lines generally occurs only when the lines are very long.
Electronic products are tested for Surge immunity to insure their continued reliable operation if subjected to realistic levels of surge voltages. The European Union’s EMC Directive currently mandates Surge testing for some products; however, it is expected that virtually all electrical and electronic products will have to be tested for Surge immunity in the near future as a condition for obtaining the CE Mark before shipping products to a member state of the European Union.
Applicable Standards
Generic Immunity, Product and Product Family Standards require Surge tests be performed in accordance with Basic EMC Standards: IEC 801-5, IEC 61000-4-5 or EN 61000-4-5. Thermo KeyTek’s Application Note, “EMC Standards Overview,” provides an overview of European Standards for electromagnetic compatibility, describes how the Standards relate to one another, and lists sources for procuring copyrighted documents.
Basic EMC Standard
The Basic EMC Standard for Surge defines the methods of generating consistently reproducible surge voltages for test purposes. They specify generator and coupler/decoupler design and performance in sufficient detail to produce correlatable results between test sites. While the Basic EMC Standard specifies how to perform Surge testing, the Generic, Product and Product Family Standards specify the test levels and pass/fail performance criteria.