How to Wire a Well Pump Pressure Switch
Well pump pressure switches control the water pump's operation on a private home well. Typically, the main electrical power, or feeder power, for the pump is connected to one side of the pressure switch. The switch, when activated, will transmit the feeder power on to the water pump. In some cases, the switched power may go to either a water pump relay or a control module. Various pump control modules may require specific wiring. Consult the manufacturers of such devices for installation. Does this Spark an idea?
Instructions
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1
Remove all electrical power from the water pump circuit. This may entail shutting off the circuit breaker or pulling fuses. Typically, most water pumps will use 240 VAC electrical power. This will mean that a two-pole circuit breaker or two fuses are employed as the over current or circuit protection device.
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2
Unscrew the retaining nut that resides on top of the plastic cover for the pressure switch. Note that there are two electrical wire holes for the cable assembly built into the metal housing of the pressure switch. Typically, the wire or cable will be made up of three separate wires, sheathed in an overall plastic insulation covering. Inside the cable assembly you'll find a black insulated wire, a white insulated wire, and a bare copper wire.
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3
Use the pocketknife to remove up to 6 inches of the outer insulation on the wire cable assembly. This will reveal the black insulated, white insulated, and bare copper wires. Feed both sets of wires through the cable holes on the pressure switch. One set of wires is coming from the main power. The other set of wires will be going to the water pump.
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4
Use the wire strippers and remove ¾ of an inch of the individual wire insulation. This should reveal the bare copper underneath the black insulated and white insulated wires.
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5
Observe the screw terminals on the pressure switch, and the related contacts they are attached to just above the screws. Note that there is one set of contacts for each pair of screws---a right hand set and a left hand set.
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6
Attach the black wire from the incoming power to one of the left hand contact screw terminals. Secure the white wire to one of the right hand contact screw terminals. Use the screwdriver to tighten the screw terminal and hold the wire in place.
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Connect the black wire going to the pump to the other screw terminal on the left hand side of the contacts. Attach the white wire going to the pump to the other screw terminal on the right hand set of contacts. You should have one wire to each screw terminal on the pressure switch.
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8
Connect the two remaining bare copper wires to the green screw mounted on the metal frame of the pressure switch. Reattach the plastic cover. Re-energize the main power for the pump circuit.
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Tips & Warnings
Follow all local codes and regulations whenever servicing or installing private home water systems.
Some local agencies may require that all work performed on a home water system be undertaken by a licensed technician.
