The 10 percent that stops your application being rejected

A 5 kW system does not exist. With 540 watt modules you can have nine, which is 4.86 kW, or ten, which is 5.4 kW. Neither is five.

For a while that arithmetic was getting applications rejected, for no engineering reason at all.

What changed

MNRE has allowed a tolerance of up to 10 percent on the applied DC capacity under PM Surya Ghar, so the declared module capacity may sit above or below the intended system size within that band. The inverter's AC rating stays where it was, within the sanctioned load or the maximum the local rules allow.

The illustration used is exactly the case above: a consumer planning 5 kW with 540 watt modules can install nine modules at 4.86 kW or ten at 5.4 kW, while keeping a 5 kW inverter.

Why it was a problem worth fixing

Rejections on this basis wasted everybody's time. The system was sound, the inverter was correctly sized, and the file came back because two numbers on a form did not match.

Worse, it pushed installers toward bad engineering to satisfy the paperwork: dropping a module to make the arithmetic tidy, or choosing a module wattage that suited the form rather than the roof.

An array is not supposed to match its inverter exactly. Modules almost never produce their rated output, so a modest excess of DC over AC capacity produces more energy across the day, which is the whole argument in why the array should be bigger than the inverter.

What it does not change

Four things stay exactly as they were, and conflating them with this tolerance is how a job goes wrong.

Sanctioned load still binds. The inverter must remain within it. See sanctioned load is the ceiling nobody checks.

The sanction letter still governs. The inspection checks what was approved. If the approval names a capacity, that is the number that matters at inspection.

Documents still have to agree. The capacity on the application, the modules physically installed, the serial numbers uploaded and the invoice must all tell the same story. A tolerance on declared capacity is not permission for the paperwork to drift, particularly now that the customer approves the agreement and the total cost through the portal, as in your customer now has to approve your agreement.

The roof still decides. A tolerance does not create space, remove a water tank or fix shading.

How to use it properly

• Design the array first, from the load, the roof and the shading, then declare what you are actually installing.
• Pick the module count that suits the roof, not the one that makes a round number.
• State the real DC capacity on the application, within the band, rather than rounding it to look neat.
• Keep the inverter within sanctioned limits, every time.
• Record the module count and wattage in the handover pack, because a future service visit or warranty claim starts from that number.

The wider point

Most of the friction in residential rooftop is not technical. It is the distance between how a system is actually built and how a form expects it to be described.

This change closes one of those gaps. The remaining ones are worth noticing as you work, because the ones that get fixed are generally the ones the industry complained about clearly and repeatedly.

The short version

• MNRE now allows up to 10 percent tolerance on the declared DC capacity under PM Surya Ghar, with the inverter kept within sanctioned limits.
• A 5 kW plan with 540 watt modules can therefore be nine modules at 4.86 kW or ten at 5.4 kW.
• It removes rejections caused by arithmetic rather than engineering, and stops installers distorting designs to fit a form.
• It does not change sanctioned load, the sanction letter, document consistency or the roof.
• Confirm with your DISCOM how subsidy is computed when declared capacity differs from the nominal size.

Sources

• MNRE Allows 10% DC Capacity Flexibility To Speed Up PM Surya Ghar Rooftop Solar Approvals, SolarQuarter, trade coverage
• PM Surya Ghar: Muft Bijli Yojana national portal, Government of India