This document includes details on the varistor requirements for the New UL and IEC Standards.pdf
A broad range of EPCOS varistors satisfies the extended requirements of the reissued UL
1449. The third edition of this overvoltage protection standard went into effect on September 29, 2009.
In recent years, the European electrical and electronics industry has reworked the safety standards for surge protective devices (SPDs) several times – in some cases with significant changes: thus the first edition of EN 60950-1 specified the mandatory use of surge suppressors. They additionally had to satisfy the then applicable UL 1449 standard on transient voltage surge suppressors (TVSS).
The second edition of EN 60950-1 stipulates that a varistor used in a primary circuit must satisfy either IEC 61051-2 or the new UL 1449 3rd Edition. Surge suppressors of non-VDR (voltage dependent resistor) type must still satisfy the requirements of the new UL 1449 when used in other applications approved by UL and classified as safety-critical components.
