Pre-Installation Preparation for Solar Inverters: 8 Core Steps + Considerations (With Professional Advice)

I. Preliminary On-Site Survey: Accurately Matching the Installation Environment

1. Confirm Installation Location and Space
   • Prioritize areas with good ventilation and no obstructions (e.g., near rooftop PV brackets, ground-based equipment rooms, or outdoor rainproof cabinets). Ensure a minimum clearance of 50 cm around the inverter to facilitate heat dissipation and future maintenance.
   • Avoid installing the inverter in locations exposed to direct sunlight (high temperatures in summer may trigger overheating protection), humid or waterlogged areas (humidity > 90% can damage circuits), or areas with high concentrations of dust or corrosive gases (e.g., near chemical plants).
   • For outdoor installation, confirm that a rainproof, sunproof, and snowproof shelter can be built at the installation site (or select an outdoor inverter with an IP rating of IP65 or higher). Additionally, the ground must be level and have sufficient load-bearing capacity (a single inverter typically weighs 10–50 kg, so the installation surface should be rated to support ≥ 20 kg/㎡).
2. Test Power Grid and Load Parameters
   • Contact the local power grid company to obtain grid connection parameters, including grid voltage level (220V single-phase / 380V three-phase), frequency (50Hz), and the maximum allowable active/reactive power for connection. Ensure the inverter’s output parameters match the grid specifications.
   • Calculate the DC-side parameters of the PV system: the total voltage of serially connected PV modules (must fall within the inverter’s MPPT voltage range, usually 200–1000V; refer to the inverter manual for details) and total power (the inverter’s rated power should be 10%–20% higher than the total module power to avoid overload).
   • Confirm whether there are backup power sources or energy storage devices (e.g., lithium batteries) on-site. If the inverter needs to support both “grid-connected” and “off-grid” modes, select a compatible hybrid inverter in advance.
3. Identify Surrounding Safety Hazards
   • Check for strong electromagnetic interference sources (e.g., high-voltage transformers, large motors) near the installation site to prevent interference with the inverter’s communication signals.
   • Ensure no flammable or explosive materials (e.g., gasoline barrels, gas pipelines) are nearby, and keep the area away from locations accessible to children or unauthorized personnel to minimize safety risks.

II. Inverter Selection: Matching System Requirements + Scenario Adaptation

1. Selection by Power Rating
   • Small residential PV systems (3–10kW): Choose single-phase string inverters (e.g., 2kW, 5kW, 8kW models) for high flexibility, which are suitable for split-string installation of modules.
   • Medium-sized commercial and industrial systems (10–100kW): Select three-phase string inverters (e.g., 15kW, 30kW, 50kW models) to match 380V industrial power grids and achieve higher power generation efficiency.
   • Large-scale ground-mounted power plants (100kW and above): Use centralized inverters (e.g., 250kW, 500kW, 1MW models), which need to be paired with combiner boxes and are suitable for large-scale centralized grid connection of modules.
2. Selection by Protection Rating and Scenario
   • Outdoor rooftop/ground installation: Choose inverters with an IP rating of IP65 or higher (IP65 is dust-tight and protected against water jets; IP67 is dust-tight and protected against temporary submersion).
   • Indoor equipment room installation: An IP54 protection rating is sufficient (dust-tight and protected against splashing water).
   • High-altitude areas (> 1000m): Select high-altitude-adapted inverters (ordinary inverters have reduced heat dissipation efficiency at high altitudes and require special design by manufacturers to avoid power derating).
3. Focus on Core Performance Parameters
   • MPPT Efficiency: Prioritize products with an MPPT efficiency of ≥ 99% (MPPT, or Maximum Power Point Tracking, maximizes PV module power output; higher efficiency means better energy utilization).
   • Conversion Efficiency: Ensure a rated conversion efficiency of ≥ 97% (this efficiency reflects the inverter’s ability to convert DC power to AC power and directly impacts power generation).
   • Communication Function: Opt for inverters that support WiFi/4G/RS485 communication, as this enables remote monitoring of power generation and equipment status (essential for future operation and maintenance).
   • Protection Functions: The inverter must include overvoltage, overcurrent, short-circuit, grounding, and islanding protection (islanding protection ensures the inverter shuts down automatically when the grid is disconnected to avoid electric shock risks, which complies with grid regulations).

III. Qualification and Compliance Preparation: Avoiding Illegal Grid Connection

1. Obtain Grid Connection Approval
   • Submit a grid connection application to the local State Grid business hall. Required documents include: an ID card (for residential users)/a business license (for commercial/industrial users), a property ownership certificate (or rooftop lease agreement), and a PV system design plan (including inverter parameters, module parameters, and wiring diagrams).
   • After the grid company approves the application, it will issue a Grid Connection Opinion Letter, specifying the connection method (e.g., 220V single-phase grid connection, 380V three-phase grid connection) and the installation location of the metering device. Keep this document for future reference.
2. Verify Installation Qualifications and Personnel Certifications
   • The installation team must hold a General Contracting Qualification for Electric Power Engineering (or a PV-specific construction qualification) to avoid safety accidents or grid connection failures caused by unqualified construction.
   • On-site installers must possess an electrician certificate (low-voltage/high-voltage) and a PV System Installation and Maintenance Personnel Certificate to ensure operations comply with electrical safety standards (the grid company in some regions may verify personnel qualifications).
3. Prepare Design and Technical Documents
   • Entrust a professional design institute or PV manufacturer to issue system design drawings, including inverter installation diagrams, DC-side wiring diagrams (connections between module strings and inverter input terminals), AC-side wiring diagrams (connections between inverter output terminals and the grid/load), and grounding system diagrams.
   • Organize inverter product documents: a product qualification certificate, a test report (must comply with national standards such as GB/T 19638.1-2022 Small Photovoltaic Inverters—Part 1: Technical Requirements), and an installation manual (must be sealed and confirmed by the manufacturer).

IV. Tool and Material Preparation: Ensuring Efficient and Safe Installation

1. Core Installation Tools (Must Be Calibrated and Qualified)

2. Essential Auxiliary Materials (Must Match the Inverter)

• Cables: Use PV-specific cables (PV1-F) for the DC side (these are weather-resistant and UV-resistant; select a cross-section based on current, e.g., 4mm², 6mm²); use copper-core XLPE cables (YJV) for the AC side (select a cross-section that matches the inverter’s rated output current, e.g., 10mm², 16mm²).
• Terminal Blocks and Protection Devices: Install DC circuit breakers on the DC side (current must match the module string current, e.g., 10A, 16A); install AC circuit breakers on the AC side (current must match the inverter’s rated output current, e.g., 20A, 32A); select copper cold-pressed terminals (to prevent oxidation and overheating).
• Brackets and Fasteners: Use hot-dip galvanized steel for inverter brackets (this material is corrosion-resistant and suitable for outdoor use), along with matching expansion bolts (select based on the installation surface material: M10 expansion bolts for concrete, self-tapping screws for color steel tiles).
• Grounding Materials: Prepare a grounding electrode (galvanized angle steel, length ≥ 2.5m), a grounding wire (copper-core cable, cross-section ≥ 6mm²), and a grounding clamp (ensure grounding resistance ≤ 4Ω, which must be tested with a grounding resistance tester).

V. Safety Protection Preparation: Eliminating Construction Risks

1. Pre-Construction Safety Training
   • Conduct safety briefings for the installation team: Clarify the live characteristics of the PV system’s DC side (modules generate voltage when exposed to sunlight, even if the inverter is disconnected) and emergency shutdown procedures (in case of electric shock, first turn off the DC circuit breaker of the module string).
   • Train personnel in electric shock first aid methods (e.g., cardiopulmonary resuscitation) and the use of fire-fighting equipment (equipped with dry powder fire extinguishers; avoid using water to put out electrical fires).
2. On-Site Safety Layout
   • Place safety warning signs (e.g., “High Voltage Danger,” “Construction Area—No Entry”) in the installation area, set up warning lines, and prohibit unauthorized personnel from entering.
   • For rooftop or high-altitude installation, build safety railings or lay safety nets, and require installers to wear safety belts (safety belts must be fixed with double hooks and worn in a “high-hang, low-use” manner).
   • Ensure the safety of temporary on-site power supply: Temporary sockets must be equipped with leakage protection (leakage current ≤ 30mA) to prevent cable damage or rolling.
3. Inverter Unpacking Inspection
   • Before unpacking, confirm that the inverter packaging is intact and the moisture-proof film is in good condition. After unpacking, check the inverter’s appearance (no shell deformation, no interface damage) and the completeness of accessories (manual, screws, terminal blocks).
   • Use an insulation resistance tester to measure the insulation resistance of the inverter’s input and output terminals (must be ≥ 10MΩ). If insulation is poor, do not proceed with installation (this may indicate internal short circuits).

VI. Post-Maintenance Plan Preparation: Reducing Long-Term Risks

1. Establish Equipment Files
   • Record the inverter’s core information: model, serial number, installation location, grid connection time, manufacturer’s contact information, and warranty period (inverters typically have a 5–10 year warranty, which can be extended to 20 years for an additional fee).
   • Keep the operation and maintenance manual provided by the manufacturer, and clarify daily inspection items (e.g., cleaning cooling fans, checking terminal block temperature, reviewing fault codes).
2. Confirm After-Sales Support
   • Confirm the contact information of the local after-sales team with the inverter manufacturer or distributor, and clarify the fault response time (e.g., on-site service within 24 hours).
   • If the inverter supports remote monitoring, configure the monitoring platform (e.g., manufacturer’s APP, cloud platform) in advance and test the data upload function (ensure normal display of power generation, voltage, current, and other key data).

Summary