Key points for installing residential solar systems on rooftops

The installation of residential solar systems on rooftops requires comprehensive consideration of structural safety, system efficiency, construction standards and operation and maintenance management. The following is an analysis of the key points:

First, roof structure and load assessment

Verification of load-bearing capacity

The static load and live load of the roof should be calculated by a professional institution to ensure that the load-bearing allowance of the concrete roof or steel structure roof meets the system requirements. For instance, the total weight of equipment such as photovoltaic modules, brackets and cables must be strictly controlled within the design load range to prevent structural safety hazards caused by overloading.

Waterproof layer protection

Before construction, it is necessary to check the integrity of the roof waterproof layer to avoid drilling or punching holes that may damage the waterproof structure. If it is necessary to penetrate the waterproof layer, special waterproof glue or metal sleeves should be used for sealing treatment, and it is necessary to ensure that a water-tightness test is conducted after construction to prevent leakage.

Second, system design and layout optimization

Orientation and inclination adjustment

Component installation should prioritize the due south direction (with a deflection Angle not exceeding ±15°), and adjust the inclination Angle according to the local latitude (usually ±10° latitude) to maximize the annual light reception. For instance, in the mid-latitudes of the Northern Hemisphere, it is recommended that the inclination Angle be 30°-40°, which can increase the power generation efficiency by 10%-15%.

Shadow avoidance and spacing planning

It is necessary to conduct sunlight simulation analysis to ensure that the component array is unobstructed from 9:00 to 15:00 on the winter solstice. Sufficient spacing should be reserved between components (horizontal spacing ≥0.5 meters, vertical spacing ≥0.3 meters) to prevent the front components from blocking the rear ones.

Third, equipment selection and installation standards

The component matches the inverter

The power of the components should be matched with the rated input power of the inverter to avoid "a big horse pulling a small cart" or "a small horse pulling a big cart". For instance, single-phase inverters are suitable for systems with a power of no more than 10kW, while three-phase inverters are suitable for systems with a power greater than 10kW, to ensure the MPPT (Maximum Power Point Tracking) efficiency.

Electrical safety and grounding

Lightning protection modules and DC circuit breakers need to be installed on the DC side, and residual current protection devices (RCD) need to be configured on the AC side. All metal components (brackets, inverter casings, etc.) must be reliably grounded with a grounding resistance of no more than 4Ω to prevent safety accidents caused by lightning strikes or leakage.

Fourth, construction and acceptance standards

Bracket fixation method

For concrete roofs, it is recommended to use chemical anchor bolts or expansion bolts to fix the brackets. For steel structure roofs, clamps or welding methods can be adopted. The spacing of the fixed points should comply with the design requirements (usually ≤1.5 meters) to ensure that the wind resistance capacity is ≥ level 12.

Cable laying and marking

Dc cables should adopt double-layer insulated cables dedicated to photovoltaic, and AC cables should comply with low-voltage distribution standards. Cables need to be protected through pipes to avoid direct sunlight and mechanical damage, and clear markings should be set up to facilitate later operation and maintenance.

Fifth, operation and maintenance and safety management

Regular cleaning and inspection

It is recommended to clean the dust on the surface of the components every quarter. After the rainy season, focus on checking for accumulated water and stains. A system inspection should be conducted once a year, including insulation resistance test (≥1MΩ), grounding resistance test (≤4Ω) and inverter efficiency test (≥95%).

Formulation of emergency response plans

Emergency plans for extreme weather conditions (such as typhoons and hail) need to be established, including measures such as component reinforcement and system power outages. At the same time, fire extinguishers and other fire-fighting equipment should be provided, and their effectiveness should be checked regularly.