3 kW On-Grid Solar Power Plant (Complete Guide) (PM Surya Ghar)

Preparing a professional quotation is one of the most important skills for every solar installer, EPC contractor, or solar entrepreneur. A well-prepared quotation not only helps win customer trust but also ensures that every material, installation activity, and service is properly accounted for.

A standard 3 kW on-grid solar power plant is ideal for homes consuming 300–450 units of electricity per month. It typically generates 12–15 units of electricity per day (depending on location and weather), helping homeowners reduce electricity bills by 70–90%.

This guide explains every component required, the installation process, testing, commissioning, labour, transportation, and a sample quotation structure.

System Capacity

• Plant Capacity: 3 kW On-Grid Solar System

• Number of Modules: 6 × 550 W Mono PERC/TopCon Solar Panels

• Total Capacity: 3300 Wp

• Roof Area Required: 220–250 sq. ft.

• Grid Connection: Single Phase

• Expected Daily Generation: 12–15 kWh

• Annual Energy Generation: 4,300–5,000 kWh

Major Components Required

1. Solar PV Modules

Solar panels convert sunlight into electricity. Modern projects generally use 550 W Mono PERC or N-Type TOPCon modules with efficiencies above 21%.

Typical Requirement

• Quantity: 6 Nos.

• Capacity: 550 W

• Total Capacity: 3300 Wp

Most manufacturers provide:

• 12-year product warranty

• 25–30-year performance warranty

2. Solar Inverter

The inverter converts DC electricity into AC electricity and synchronizes with the utility grid.

For a 3 kW plant:

• Capacity: 3 kW

• MPPT: 2

• Wi-Fi Monitoring

• Anti-Islanding Protection

• IP65 Outdoor Rating

3. Mounting Structure

The mounting structure supports solar panels against wind loads and corrosion.

Recommended Material

• Hot Dip Galvanized Iron (HDGI)

• Galvanization: 80–120 Microns

Structure Size

• Tilt Angle: 18°–25° (location dependent)

• Clearance from Roof: 1–1.2 m

• Wind Resistance: Up to 180 km/h

Structure includes:

• Legs

• Rails

• Purlins

• Module Clamps

• Fasteners

4. DC Cables

Special UV-resistant solar cables connect panels to the inverter.

Recommended:

• 4 sq.mm Copper DC Cable

• Double Insulated

• UV Resistant

• TUV Certified

Approximate Length

• 40–60 metres

5. AC Cable

Carries AC power from inverter to ACDB.

Recommended:

• 4 sq.mm Copper Cable

• FRLS

• ISI Marked

Approximate Length

20–30 metres

6. MC4 Connectors

MC4 connectors ensure waterproof electrical connections.

Required:

• Male Connectors

• Female Connectors

• Branch connectors (if required)

7. DCDB (DC Distribution Box)

Provides protection between solar panels and inverter.

Includes:

• DC MCB

• DC SPD

• Fuse

• Isolator

8. ACDB (AC Distribution Box)

Installed between inverter and main distribution board.

Contains:

• AC MCB

• SPD

• Changeover (optional)

• RCCB

9. Earthing System

Proper earthing protects equipment and users.

Recommended:

• GI Earthing Electrode

• Earth Pit Chamber

• Salt

• Charcoal

• Earthing Strip

Normally three separate earth pits are installed:

• Solar Structure Earthing

• Equipment Earthing

• Lightning Earthing

10. Lightning Arrester

Protects the plant during thunderstorms.

Recommended Height:

• 2–3 metres above panel level

Includes:

• Air Terminal

• Down Conductor

• Earth Connection

11. Fasteners

Use corrosion-resistant fasteners.

Includes:

• SS Nut Bolts

• Spring Washers

• Plain Washers

• U-Clamps

• Module Clamps

12. Cable Management

Neat cable routing improves safety.

Required:

• UV Cable Ties

• PVC Conduit

• HDPE Pipe

• Cable Tray

• Junction Boxes

Solar Panel Cleaning System

Regular cleaning improves energy generation.

Recommended Equipment

• Soft Brush

• Water Pipe

• TDS Water

• Extendable Cleaning Pole

• Safety Harness

Cleaning Frequency

• Every 15–20 days

• Weekly in dusty areas

Solar Plant Installation Procedure

Step 1

Conduct detailed site survey.

Check:

• Roof strength

• Shadow analysis

• Panel orientation

• Roof dimensions

Step 2

Mark foundation points.

Step 3

Install mounting structure.

Ensure:

• Proper alignment

• Tight bolting

• Correct tilt angle

Step 4

Install solar modules.

Follow torque specifications while tightening clamps.

Step 5

Connect DC strings.

Verify:

• Polarity

• Open Circuit Voltage

• String Current

Step 6

Install inverter.

Maintain:

• Proper ventilation

• Weather protection

• Easy maintenance access

Step 7

Connect AC and DC cables.

Step 8

Install DCDB and ACDB.

Step 9

Complete earthing and lightning protection.

Step 10

Final inspection before energization.

Testing Procedure

Before commissioning, perform the following tests:

✔ Open Circuit Voltage (Voc)

✔ Short Circuit Current (Isc)

✔ Insulation Resistance Test

✔ Earth Resistance Test

✔ Polarity Test

✔ Inverter Functional Test

✔ SPD Verification

✔ AC Voltage Measurement

✔ Grid Synchronization

✔ Energy Meter Testing

All readings should comply with the manufacturer's specifications and relevant electrical standards.

Commissioning Procedure

After successful testing:

• Switch ON AC supply.

• Switch ON DC isolator.

• Start the inverter.

• Verify grid synchronization.

• Check inverter display and monitoring portal.

• Record generation data.

• Hand over system documentation to the customer.

Provide:

• Warranty certificates

• User manual

• Test reports

• As-built drawings

• Maintenance schedule

Labour Requirement

Typical manpower:

• Site Engineer – 1

• Electrician – 1

• Solar Technician – 2

• Helper – 2

Installation Time:

1–2 days

Transportation

Transportation charges depend on:

• Distance

• Roof accessibility

• Crane requirement

• Material handling

Include:

• Loading

• Unloading

• Local transport

• Packaging

Net Metering and Approval Procedure

After installation:

1. Submit application to DISCOM.

2. Upload plant documents.

3. Electrical inspection (if applicable).

4. Net meter installation.

5. Grid synchronization approval.

6. Final commissioning certificate.

Required documents include:

• Customer ID proof

• Electricity bill

• Property ownership proof

• Single-line diagram

• Solar module and inverter datasheets

• Installation photographs

• Test certificates

Sample Quotation Format

Project: Installation of 3 kW Grid-Connected Rooftop Solar Power Plant

Scope of Supply

• 6 × 550 W Solar Modules

• 3 kW Grid-Tied Inverter

• HDGI Mounting Structure

• DCDB

• ACDB

• DC & AC Cables

• MC4 Connectors

• Earthing Kit

• Lightning Arrester

• Cable Accessories

• Installation

• Testing

• Commissioning

• Documentation

• Net Metering Assistance

Scope of Work

• Material Supply

• Transportation

• Installation

• Electrical Wiring

• Earthing

• Testing

• Commissioning

• Customer Training

Exclusions

• Civil modifications (if required)

• Roof waterproofing

• Additional electrical work beyond agreed scope

• Government application fees (if applicable)

Warranty

• Solar Modules: 25–30 Years Performance Warranty

• Inverter: 5–10 Years (manufacturer dependent)

• Structure: 10 Years against corrosion

• Installation Workmanship: 1 Year

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