Here's the situation. We have tried to replace a "non-clogging Submersible" pump that has been in service for 20+yrs and are experiencing catistrophic failures. The new pumps are the same rating as the old (as far as nameplate data goes) and nothing has changed to the electrical system. The electrical feed consists of a wye-delta transformer to give 240VL-L, with a tap off of one of the windings to give 120L-N... leaving C phase as the bastard-leg. However this should have no impact on the pump as it is 240V 3phase. The pumps housing are being blown apart and it appears that source of the "explosions" may be coming from the case ground connection, but it is difficult to tell. We've gone through 3 pumps from two manufacturers. We've also just added line monitoring to check for harmonics, voltage & current etc. And have only noticed so far that the voltage dips during startup, which is normal. These pumps run for a length of time before failing. Here is the nameplate specs from one pump: 5HP, 208/230V, 3ph, 60Hz, 1750RPM, FLA 17.0/16.0, Ins.Class B, Code B D, Impeller Dia 7.00 And some info from the supply panel that feeds the pumps (located btw the pole transformer and pump): 3.7kW-5HP, 1745RPM S1, 3ph, 60Hz, Yser460/Y//230KV 6.8/14A cos 0.81 Any information would be greatly appreciated as we are scratching our heads with this one.