The new TCMOV34S Series Varistor is designed specifically to protect high energy circuits from the short circuit (SCCR) conditions and Abnormal Overvoltage Intermediate Current conditions specified in the 3rd edition of UL1449 for Type 1 or Type 2 SPD applications. It combines high maximum surge capability (50kA) with an integrated thermally active element. In addition to suppressing voltage transients by clamping them to a safe level, the 34mm-square-format TCMOV34S Series Varistor is designed to disconnect itself from the circuit safely in the event of overheating due to abnormal over-voltage conditions. A built-in micro-switch can be used to indicate when the Varistor is disconnected from the circuit. The micro-switch is triggered by a mechanical slide for indication option, and the switch could make the indication circuit completely isolated from the primary circuit. The TCMOV34S Series provides a Short Circuit Current Rating up to 200kA.

The new Littelfuse SMOV25 and SMOV34 Varistor Series are designed to disconnect themselves safely from the circuit in a sustained over-voltage, intermediate current condition as outlined  UL1449 (3rd edition). Their standard operating voltage range is compatible with common AC line voltage (115VAC to 750VAC). Both Series are designed to help manufacturers meet requirements in UL1449 (3rd edition) for Type 2 or Type 3 SPDs.