Zoeller 4163-0032 Model MX4163 Explosion Proof Effluent Pump 0.5 HP 115V 1PH 50' Cord AutomaticZoeller Model MX4163 Explosion Proof Effluent Pump Description Our Model MX4163 is the industry's only automatic explosion proof effluent pump rated for Class 1, Division 1, Groups C & D or Class 1, Zone 1, Groups IIA & IIB. The 1 2 HP MX4163 is a fully automatic effluent pump that is equipped with a brass float that prevents sparking in hazardous locations. The Pump's vortex impeller allows it to pass 3 4" spherical solids. The impeller's clearance