Coordination of MOV type lightning arresters and current limiting fuses

Questions of the coordination of current limiting (CL) fuses and MOV-type lightning arresters are examined. Results are presented from a brief test program done to verify the conclusions reached, based on a review of current standards and typical systems. It is concluded that current selection practices should allow use of arresters in front of CL fuses without undue risk. The probability of damage is very low as long as devices which reflect current standards are used. It is noted that the conclusions reached 20 years ago by the working group on arrester and fuse coordination apply equally well to current MOV-style arresters and the earlier gapped arresters. This is especially true when CL fuses with elements designed to control peak arc voltage are used. Other fuses, such as the 12 A and smaller sizes listed in the standards, which do not control peak arc voltages may cause different results. >