How much roof area is required to install a rooftop solar PV system?

Size of a rooftop solar PV system depends on the roof area available for installing the solar panels. It is very important to ensure that no shadow falls on the solar panels throughout the year therefore, it becomes very important to calculate the available shadow-free area out of the total roof area for installing the solar panels. According to the rule of thumb, 10 square meters shadow-free area is required for installing a 1-kilowatt rooftop solar system.   Read more

Cables used in a solar rooftop system

The cables used in a solar PV system transport the electricity generated from the system to the load. The cables used in the system used can be classified as Alternating Current (AC) or Direct Current (DC) cables. The DC cables carry the power from the PV modules to inverters, whereas the AC cables carry the AC power from the inverter to the metering point. DC Cables: Solar DC cables interconnect solar panels to the combiner boxes to an inverter. The DC cables are usually two-core cables, a current-carrying live wire, and a negative wire, both are typically surrounded by an insulation layer. DC cables are generally made of copper conductors which provides more flexibility. As the life of the solar plant is expected to be more than 25 years, DC cables should be capable to withstand high temperatures, UV radiations, fire risk, exposure to water, etc. There are two types of solar DC cables: Module cables: These cables are usually integrated into the PV solar panels and are equipped with suitable to be interconnected. fig: Module DC Cables     Main cables: The extension cables used to connect the module strings to the DC combiner boxes or the inverter. AC Cables: The AC cables connect the inverter to the load via protection devices. In the case of three-phase inverters, the connection to the low voltage grid is made using five-core AC cables (three live wires for the three phases that carry the current, a neutral wire carry current away from the device and ground wire […] Read more

Can a mounting structure cause damage to my roof?

Many property owners worry about damaging their roof on installing a rooftop solar PV power plant. However, as these installations will last at least for 25 years, so it is important to make sure that all pre-existing damage to the roof is assessed and repaired, if needed. It is also to be noted that the installation being done should be well within the safety limits and it should be able to withstand the weight of an additional structure without any structural damage, leakage and water logging, etc. PV module mounting structures designed and installed correctly do not cause damage to the roof. The spacing of brackets and purlins spreads the weight of the solar panels across a large cross-section of the roof area. If you have a flat roof, you won’t need to put holes in it for installation. Installations on flat roofs commonly use ballast mounting systems which involve no holes. A few examples of ballast mounting structures used widely these days are: Roof damage as a result of a solar PV power plant installation is extremely rare because installers take precautionary steps while installing the structure and the solar panels. However, if property owners are concerned about damage to the roof, they can question the installer about their installation process, measures they take to prevent roof damage and workmanship warranty, and check whether it covers the roof damage in case it occurs. Read more

How does temperature affect solar panels?

Solar panels react differently to the operating temperature. The efficiency of a solar panel decreases as it increases above the ambient temperature. Each solar panel has a temperature coefficient (which is defined in datasheet of panels). The temperature coefficient represents the rate at which the panel will underperform at each increase in degree Celsius (°C). Most panels have a temperature coefficient of between -0.2% /°C to -0.5%/°C, when tested under standard laboratory conditions, where ambient temperature is set to 25°C. For example if the temperature coefficient of a particular type of panel is -0.5%, then for every 10C rise, the panel’s output power will reduce by 0.5%. [Source: Youtube] [Publisher: altE Store’s Educational Video Channel] Read more


Metering of the solar rooftop system allows the measurement of the total number of units generated by the system and consumed/ exported by the owner. By analyzing the metered data the owner/ developer of the system may take corrective actions to improve productivity.             The type of metering would depend on your agreement with the local electricity distribution company. The three major types of metering arrangements used in India are net-metering, gross-metering & captive consumption. You may know more about the metering by clicking the button below. Read more

How can I check if my roof is suitable to install solar PV?

A quick inspection of your roof is the first step in determining if you can install a rooftop solar PV system on your roof. The following are a few factors that one can check (before the installers) to know if the roof is suitable for the installation of solar PV. 1. Roof orientation  The best position for solar panels is towards the south, but even west- and east-facing roofs can accommodate solar panels. However, you should keep in mind that skylights, air-conditioning units, and pipelines etc. installed on the roof can affect overall available space for the installation of solar panels. 2. Shading on the roof It is important to take note of the shading caused by nearby water tanks, antennas or buildings & trees. These objects can have an effect on the performance of the solar PV system by causing obstructions between the sunlight and the solar panels. If you have a high-rise building casting a shadow on the complete roof area, installing solar panels on this roof may not be ideal, it would be better to avoid the installation in such shaded areas. 3. Age of the roof The age of the roof/building is also one of the important factors primarily in the metal/asbestos roofs. Although the solar PV installation expert will study the roof profile in detail before designing and installation, here are a few points that can be observed: Loose or broken tiles Punctures and cracks Standing water/leakages Any type of structural damage The video explains […] Read more

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