Borewell Pump Installation Guide: Step-by-Step

Installing a submersible borewell pump correctly the first time saves you from the most expensive failure mode: dropping the pump down the borewell. This guide walks through the complete process from pump selection through commissioning, with the safety checks that experienced installers know but often don't document.

1. Pre-Installation — Borewell Survey

Before specifying the pump, the borewell driller should provide:

• Borewell depth: Total bored depth in metres
• Casing depth: How deep the MS or PVC casing extends
• Yield test: Litres per hour the borewell sustainably delivers
• Water level — static and dynamic: Standing water level and water level after pumping for 1 hour
• Casing inner diameter: Determines maximum pump diameter

2. Pump Selection

• Pump diameter: Choose 3", 4", or 5" pump to fit the casing with 25 mm clearance minimum (e.g., 4" pump for 4.5" casing)
• Head rating: Should equal static water depth + delivery pipe friction + overhead tank height + 10% margin
• Power: Calculate from required flow × head. Typical residential borewell pumps are 1–3 HP single-phase or up to 7.5 HP three-phase
• Pump position: Mount pump at least 3 m below dynamic water level, but never within 2 m of borewell bottom (silt damage)

3. Materials Checklist

• Submersible pump + matched motor (factory-coupled for residential, bolted for industrial)
• UV-stabilised water-grade delivery pipe (HDPE 6 kg/cm² or PVC) — length = pump setting depth + 6 m above ground
• Submersible flat cable (3-core for single-phase, 4-core for three-phase) — same length as pipe + 10 m extra
• Cable splice/jointing kit (waterproof, heat-shrink type) — at pump connection
• Pipe clamps (cable to pipe) at 3 m intervals
• Safety rope (high-strength nylon, 8 mm thickness)
• Control panel: DOL starter with overload, dry-run protection, voltage stabiliser if needed
• Non-return valve (NRV) at delivery
• Pressure gauge and gate valve at borewell head

4. Pre-Installation Tests

Before lowering the pump, perform these tests on the dry, assembled pump:

• Insulation Resistance (IR) test: Megger test motor windings to earth — should be >2 MΩ minimum, ideally >10 MΩ
• Winding continuity: Verify continuity between R-Y-B (three-phase) or main-start-common (single-phase)
• Rotation check: Bench-run the pump for 1–2 seconds and confirm impeller rotation matches the arrow marked on pump (for three-phase only)
• Cable joint integrity: Heat-shrink joints to pump should be waterproof to at least 30 m depth — test in a bucket of water if possible

5. The Lowering Process

Two or three people minimum — never solo:

• Lay the borewell pipe, pump, and cable on clean ground or tarpaulin
• Connect first 6 m of pipe to pump discharge with adhesive solvent (PVC) or fusion (HDPE)
• Connect waterproof cable joint at motor and seal with heat-shrink (test the joint by tugging firmly)
• Tie safety rope to the pump's top eyebolt
• Use a tripod with chain hoist or rope-and-pulley to lower the pump section by section
• At each section: join the next pipe, clamp the cable and safety rope to the pipe at 3 m intervals
• Lower slowly — sudden drops can break joints or pierce cable insulation against casing
• When pump reaches design depth, secure the pipe at the borewell head with a flange or wellhead seal

6. Electrical Connection

Connect cable to the control panel through proper cable glands. Wire:

• Three-phase: R, Y, B to motor terminals via contactor and overload
• Single-phase: Main, Start, Common — with starting capacitor matched to pump rating (don't guess capacitor value)
• Earth: Always connect dedicated earth wire from the motor frame to the plant earth pit
• Voltage stabiliser if supply varies more than ±10%
• Dry-run protector — essential to prevent burnt windings when water level drops below pump

7. Commissioning

• Open the delivery gate valve fully
• Start the pump and watch for at least 30 seconds — pressure should build smoothly to design
• Measure starting current (should be 5–7× FLC for the first second, then settle to FLC)
• Measure running current on all phases — must be balanced within 5%
• Verify discharge flow matches expected (use a stopwatch and bucket if no flow meter)
• Check that NRV holds pressure when pump stops (no back-spin)
• Note: water may run muddy for first 30 minutes — normal flushing

8. Common Mistakes That Wreck Pumps

• Pump too close to borewell bottom — sucks silt
• Pump too high in borewell — runs dry frequently
• Cable splice not waterproof — short circuit and burnt motor within weeks
• No dry-run protection — pump runs dry and burns out during water-level drops
• Single-phase motor with wrong capacitor — burnt windings or refusal to start
• No earthing — safety hazard and motor damage from leakage current
• NRV missing — water column slams back when pump stops, breaking pipe joints

Bombay Engineering Syndicate supplies complete Crompton borewell pump kits — pump, motor, cable, capacitors, control panel, and accessories — for homeowners, plumbers, and contractors across Maharashtra and Gujarat. Our team helps with pump sizing based on your borewell yield report and provides installation guidance. Contact us for borewell pump quotation and commissioning support.