The Line Isolation Monitor (LIM) performs and internal voltage check. The test is looking for the following condition (L1 to GND + L2 to GND >= L1 to L2). If the LIM fails this condition, then it will display error 8.18. Typically, the error code exists when there is some type of surge suppression present on the isolated power system. If power strips are used on the system this can cause the issue. The first step would be to turn off individual circuits on the system and see if the error code goes away. This will allow isolation to determine what is causing the error code. Once the cause of this error is removed, the code will clear from the LIM.
Released for: Schneider Electric Macedonia
