Submersible Pump Installation Step by Step
From pre-installation checks and the cable splice to lowering the pump and commissioning: the steps of a submersible pump and motor installation. A correct installation prevents most failures before they happen.
Pre-installation checks
Verify the nameplate
Check that the voltage, frequency and power on the motor nameplate match the site supply and the pump. 50 Hz and 60 Hz motors are not interchangeable.
Confirm the well dimensions
Check that the casing internal diameter leaves room for the pump, motor, cable and cable guards. Record the well depth and screen position.
Prepare the well
The well should be cleaned and developed, ideally with a pumping test completed. Lowering a pump into a sandy well shortens its life from day one.
Check the motor fill
For water-filled motors, check the fill according to the manufacturer instructions.
Turn the shaft by hand
Confirm that the pump and motor shafts turn freely by hand. A stiff shaft can indicate transport damage.
Measure insulation
Measure and record the insulation resistance of the motor and cable before installation.
Preparing motor, pump and cable
Couple the motor and pump
Align the coupling and tighten the bolts evenly in a cross pattern. After assembly, check that the shaft still turns freely.
Make the cable splice
Join the motor lead and the drop cable with a properly rated, watertight splice kit. Keep the number of splices to a minimum; every joint is a potential water ingress point.
Measure after splicing
Measure the insulation resistance again once the splice is complete. This prevents a fault that would only appear after the pump is in the well.
Check the cable cross-section
The cable must be sized for motor current, total cable length and supply voltage. See the cable sizing guide.
Lowering the pump into the well
Use proper lifting equipment
Use a crane or installation frame; never carry or lower the pump by its cable.
Attach a safety rope
A stainless steel safety rope attached to the pump keeps it from falling into the well if a pipe joint fails.
Fix the cable to the pipe
Secure the cable to the rising main at regular intervals with clamps or cable guards so it cannot chafe against the casing during starts and stops.
Seal the pipe joints
Check every pipe joint for tightness. A small leak inside the well causes loss of flow and pressure.
Lower without impact
Lower the pump steadily without striking the casing. If it catches, do not force it.
Setting depth
Where should the pump hang?
The pump must stay comfortably below the dynamic water level, with margin for seasonal decline, and far enough above the well bottom that settled sand is not drawn into the intake. If the pump is to be installed below the screen or inside a wide casing, a flow sleeve is needed so that water still passes the motor. See the pump selection guide.
Well head and control panel
Non-return valve
Prevents backflow and reverse rotation of the pump when it stops. Very deep installations may need additional non-return valves along the pipeline.
Valve and pressure gauge
A valve and pressure gauge at the well head let you see the duty point at commissioning and during later checks.
Well head cover
Keeps debris and surface water out of the well and protects the cable.
Protection devices
The panel should include an overload relay set to the motor rated current, dry-run protection and a phase failure relay.
Starting method
Direct-on-line starting is common at lower ratings. On larger units and long pipelines, star-delta, soft starters or variable frequency drives reduce stress.
Commissioning
Check the direction of rotation
Run the pump very briefly and note the pressure, then swap two of the three phases and repeat. The direction that gives the higher pressure is correct.
Start with the valve partly open
Keep the valve partly open at first start. If the water comes out sandy, keep the flow low until it clears.
Measure current
Check that the current on all three phases is balanced and below the rated current on the motor nameplate.
Measure voltage
Measure the supply voltage at the motor while running; a marked drop at start points to a cable or supply problem.
Watch the water level
During the first hours, confirm that the dynamic water level stays comfortably above the pump intake.
Record the readings
Record flow, pressure, current, voltage and dynamic water level. These values become the reference for any future troubleshooting.
Common installation mistakes
Carrying the pump by its cable
The cable and splice are damaged and an insulation fault develops.
Not checking the direction of rotation
A pump running in reverse delivers little water, and the problem can go unnoticed for years.
Running without protection
Motors running without dry-run and phase protection are the ones that fail most often.
Not fixing the cable to the pipe
The cable chafes against the casing and wears through.
Setting the depth from the static level
When pumping starts the level drops and the pump may run dry.
Frequently asked questions
How do I check the direction of rotation of a submersible pump?
Run the pump very briefly in both directions and compare the pressure or flow. The direction giving the higher pressure is correct. A pump running in reverse still delivers some water, so simply checking that water comes out is not enough.
Is a safety rope necessary?
Yes, it is recommended. If a pipe joint loosens or breaks, the rope keeps the pump from falling to the bottom of the well and greatly reduces recovery cost.
What should I do if the pump delivers sandy water at first start?
Throttle the valve to reduce the flow and run like this until the water clears. If sand continues, the well has not been developed sufficiently; see the sand guide.
Can FANPO support my installation?
Yes. Contact our technical team with the well data and the selected model through the contact page.
Prepared by the FANPO engineering team · Last updated: 8 November 2026