Technical instructions


VARSI reserves the right to modify the specifications and designs at any time under its policy of constant product improvement. The data included in the written publications is intended to clearly present comprehensive product data and provide technical information that will help the user with the design applications. However, due to possible inaccuracies, no responsibility is assumed. The information presented in the VARSI publications does not form part of any quotation or contract. It has been carefully checked and is believed to be accurate and reliable and may be changed without prior notice. Once the product has been selected, it should be tested by the user in all possible applications.


Store varistors in original packaging at temperatures ranging from -10 °C to +40 °C and relative humidity of less than 75 %. Avoid storing in the environment with rapid changes in temperature, direct sunlight, corrosive gas or dust; avoid contact with any liquids and solvents. Do not expose varistors to intense vibration and do not install them in places dose to the flammable substances. Storage time for the bare disc ceramics (with and without soldered terminals) is limited to max. 6 months from the manufacturing date in the original packaging. Storage time for the other varistor series (epoxy coated, encapsulated into the housing) is limited to max. 12 months from the manufacturing date in the original packaging.

Handling and processing

Avoid contamination of the MOV surface during storage, handling or processing. Use gloves when handling and/or processing bare disc ceramics. Handle MOVs with caution – MOV must not be dropped or handled with any kind of force. Do not apply any voltages, currents or energy ratings exceeding the specified limits.


Potting, gluing and sealing using aggressive compound can produce chemical reaction in MOV disc and can degrade electrical characteristics. Overloading MOV assembly may result in the raptured packages and the expulsion of hot materials. Make appropriate measures to physically shield the MOV from the other components. VARSI gives no guarantee for varistors purchased as bare disc versions without electrodes and coating. Improper soldering and/or finalization process may severely affect varistors’ characteristics and therefore Varsi cannot be held responsible for the quality of the bare disc varistors.