Site survey for Rooftop Solar plant: 5 things you should not miss

The outburst of COVID in India since June 2020, we at Bigwit Energy have experienced a surge in calls where the customers want to install rooftop solar plant on their roofs, though with the same time want to keep the physical interaction as low as possible. Also to various restrictions in inter-state or intra-state travel we were not able to carry out our usual site visits. Yet we found out that multiple potential customers were willing to conduct a site visit themselves and confirm the order with us. If you also want to do your own site survey for a rooftop solar plant for you, read on till the end.

BigWit Energy managed to install 180kW for 32 residential customers where the customers conducted their own site visit with our guidance on call!

Customers who generally don't have any idea about rooftop solar plants ask the most interesting doubts and as a solar company we always take it on ourselves to satisfy their doubts first and then let them decide the best solution for them with guidance.

With site survey being not suggested, here is the list of 5 things we encourage our potential customers to do individually so as to help them understand various aspects of the rooftop solar plant and its benefits for them.

1. Electricity bill reading and calculation of your Solar Plant Size:

Calendar and bills to bay

The most important thing you should do is to determine the size of the solar plant for you. There are various tools and calculators on the internet where you can put in your electricity consumption reading and the calculators can then suggest you the optimum size. But, we encourage you to understand as to why that size is the best for you. Simply, take your latest electricity bill and observe the reading of units (We are not interested in the amount, but the units i.e kWhr, consumed) consumed per month. Generally, all over India DISCOMs print readings of previous 1 year consumption along with the current month reading. You can simply take a average of those readings so you get your average electricity consumption over the year, as it will vary during summers and winter due to AC, geysers and heaters usage. Do note: some DISCOMs provide readings once every two months, you need to take average accordingly. Keep this figure in mind. Generally, a 1kW rooftop solar plant installed in India is considered very conservatively to generate about 4 units in a day. This translates to 120 units in a month. Now simply divide your average consumption units by 120, which will give you the optimum rooftop solar size for your house! In case you get a decimal figure, round off to the lower side if the figure is above ".7" Process in steps: - Calculate average units consumed by you over year by looking at your latest electricity bill - Divide the average units by 120 (Conservative generation by 1kW) - Round off the answer to the lower whole number. This is the size of solar plant requirement for you.

Installation of rooftop solar

2. Rooftop area: Now that you have the size of rooftop solar plant required for you, multiply that by 100 as 1kW generally occupies 100sqft. Thus if your requirement is for 5kW, then 5X100=500sqft. You can get the exact space required by knowing that one solar panel which can give output of 350wp - 500wp (depending upon the type and make of panel you opt for) occupies 3.3 foot X 6.6 foot. For a 5kW plant, you require 10 solar panels of 500wp. We need to point the rooftop solar plant towards south side, as India is in the Northern hemisphere. Try to keep the plant as much as to face the true south, you can use the compass in your mobile phone for this. Now simply allocate the sqft area calculated above to your rooftop area, in a rectangular manner with length to breadth ratio of about 1:1.5. The area allocated should have no shadow issues from 9am to 4pm from shadow of nearby structures or trees. There are various apps you can download on your phone to check the path of the sun during the day and seasons to see if there is any shadow problem. We would be installing the plant at a standard height of 5feet, thus smaller than 5ft structures shadows can be ignored. Try to allocate more than one such area, so that you can finalise on one after going through the next point. Guide on choosing the best solar panels here.

3. Solar Inverter and Components place: Solar inverter and the junction boxes are installed as near to the panels as possible to avoid DC losses. If you have a vertical wall on your roof somewhere, you can fix that place to install the solar inverter. Good make solar inverters are IP67 protected and can handle heavy rains as well. But, to protect it from sunlight and avoid heating issues, its better to install the inverter and junction boxes with a covering sheet on the top. After all its going to be there for 25 years! Once you decide the place where the inverter is to be installed, you can then simply choose to the rooftop area for panels nearest to this wall. Alternately, you can install the solar inverter on the solar panels structure as well if your roof does not have a vertical wall. Guide on choosing the best solar inverter here.

Solar inverter with junction boxes

4. Wiring routes and earthing location: Rooftop solar plant has typically three kinds of wires running, AC cable, DC cable and the earthing cable. Out of these, DC cables will run only from the solar panels to the solar inverter. AC cable would run from the solar inverter to your distribution box, where your meter is installed. And earthing cable would run from your roof to the three earthing done in the ground. Keep in mind the best route is the shortest route to as it will avoid all kinds of losses and extra expenses. The 3 earthing done are for AC side, DC side and Lighting Arrestor. If you have a personal garden, then that is the best place to do earthing. One earthing takes about 20cm circle space. The earthing space should be near to the route of wires so that the length of earthing cable is not unnecessarily increased, and also for aesthetic purposes as a cable running across your garden wont look good!

5. Maintenance and cleaning Access: The most ignored point even when a qualified solar technician does a site visit, is the maintenance access for the plant. Some times, there are obstacles which are ignored during installation of the solar plant but they cause hindrance or block easy access to certain points in the plant for maintenance purposes. So, its very important to identify and modify the obstacle to have a clear access to the whole solar plant when needed. The solar plant requires cleaning at-least monthly during the non-raining months so that their performance is optimal. Thus, keep this in mind and if possible make ready a quick access to water such as installing a tap on the roof. Extremely small and quite cheap water pumps can be installed in case the rooftop solar plant is installed above the level of your tank. Doing so, will have a easy access to water and will encourage you later to keep the plant clean.

Cleaning of solar panels in process

Planning to do maintenance of your plant on your own ? Click here for DIY steps

For more knowledge on rooftop solar plants and the journey of going solar, check out the useful links section below!


If you want to be the part of BigWit solar rooftop family, you can give us a call on 7082955224 or send us a mail on BigWit Energy is one of the best solar companies in Chandigarh, Mohali, Punjab, Panchkula and all of North India and we offer EMI plans of upto 3 years for our customers pan India!

Alternatively you can schedule a callback from us at your preferred time over here.


Useful Links: Working of On-Grid solar plants here.

FAQs before installing solar plant here. Accelerated rooftop solar Installation with BigWit Energy 10kW installation case study A Solar story Why to install rooftop solar plants

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