05-08-2000 Council Packet - Laserfiche WebLink

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3. Pumping Stations. In order to standardize installation and electrical connection methods, the following pumping station requirements must be met in addition to Minnesota Rules Chapter 7080; (a) Electrical Connection. (1) A water-tight, lockable electrical box must be mounted on a 4x4 inch treated redwood or cedar post. (2) All electrical connections shall be made within the box. Pump connection must not be made using a direct line (plug in only). Wire entry to the electrical box shall be sealed with a watertight material such as foam or putty. (3) Alarm and pump floats shall be on separate electrical circuits. (4) Electrical wire from power supply must not run over any tanks but must be laid beside the tanks and placed in conduit along the electrical post. (5) Electrical cords from the pump and floats must be run through a 2 i ich PVC (or equivalent) conduit (Schedule 80) with a one inch gap between the conduit and the electrical box. Electrical cords must not run through or under manhole cover. Wires must not have ground contact. (b) Pumping Chamber. (1) Effluent pipe exiting the pumping chamber should be laid on a uniform slope up to the soil treatment area for proper drainback. If the pipe at the tank must be lower than union to get elevation for drainback, a 1/4 inch weep hole must be used. (2) When the soil depth above the pressure distribution pipe is less than 3 V2 feet, insulation must be added to achieve an insulating factor equal to 3 Vi feet of soil to decrease the potential for freezing (styrofoam or concentric piping are acceptable methods). Piping under hardcover such as tennis courts or driveways shall receive an additional 1 foot of soil cover or equivalent insulating factor. (3) A reserve capacity equaling 75% of the anticipated daily flow must be allowed in the pumping chamber between the alarm activation level and the pump tank inlet. 4. Drainflelds. (a) Trenches. Trenches must meet Minnesota Rules Chapter 7080 and may not be located on slopes greater tnan 18%. (b) Mounds and At-Grades. Mounds and at-grades must meet specifications per Minnesota Rules Chapter 7080 and may not be located on soils with percolation rates slower than 120 mpi. Mounds or at-grades may be placed on slopes up to 12% with soils having a percolation rate of 0.1-30 mpi and a soil texture of sand, fine sand, sandy loam, or loam. Mounds Page 9 of 16