MOV Suppressor Safety

Important Alert:  CPSC Recalls 15 million surge protectors.  Click here for information.

If you are using an MOV type surge suppressor or are considering their use, please read the following:

  • MOVs wear out and must be replaced every 6 months to 3 years depending on the surge environment. The “protection working light” is proof the manufacturer expects their product to fail, making their use a real gamble!
  • Failed MOVs may flame, smoke, or open a fuse, removing power from critical equipment.
  • Most MOV suppressor ratings are based on calculations, not actual endurance testing.
  • MOVs used in “all three modes” actually endanger networked equipment, and can degrade audio, video and computer signals.


  • Avoid using suppressors in plastic housings. Metal housings will impede MOV fires better.
  • Do not place MOV suppressors on carpeting, near curtains or other flammable surfaces.
  • Shake the suppressor periodically and listen for loose parts. Discard if it rattles.
  • If the housing has burn marks (soot, discoloration), discard immediately.
Check with Underwriters Laboratories to see if a manufacturer has had its products tested for endurance and performance (Adjunct Classification) as well as safety or ask the company for the test results from another Nationally Recognized Testing Laboratory (NRTL). If a product is not rated for performance and endurance, its use is simply a dangerous gamble.

Additional safety information:  Information on surge protector recalls.