Thanks for all the input!! Now let me answer the ones I can at this point. Grounding impedence unknown, buried grid construction. It is an air-break and was operated about once per day for up to 10 hours duration. It failed upon closing. Annual cleaning/visual inspection. Humidity was between...
Need ideas as to how this contactor blew up. GE Limitamp IC 2814 circa 1977. No operating data (jogging etc) available other than weather was clear. Services 2400V 450 HP pump motor. Coil is original AC type and appears to be in good shape though resistance is low (0.1 ohm). Were explosions...