MOV Safety Info

Information to help prevent catastrophic damage.

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.

burnt surge suppressor 1

burnt surge suppressor 2

Safety Precautions

  • 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.

If a product claims to have safety certification, the product label or manufacturer’s web site will have the information posted. You should be able to verify certifications on the testing laboratory’s web site using the manufacturer’s file number.