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TL;DR: An on-grid solar inverter stops working the moment the grid fails, and this is a legal requirement rather than a fault. Regulation 11(6)(e) of the Central Electricity Authority’s connectivity regulations requires a grid-connected system to cease energising the network within two seconds of an unintended island forming, and Regulation 11(6)(d) blocks reconnection until voltage and frequency have been stable for at least sixty seconds. A household with a 3 kW on-grid rooftop system therefore sits in the dark during an outage while its panels are in full sun. Backup during a cut requires either a hybrid inverter with a battery or a separate lithium inverter on an essentials circuit. The PM Surya Ghar subsidy of up to Rs 78,000 applies to the grid-connected solar system, not to backup capability.
What Is an On-Grid Solar Inverter?
An on-grid solar inverter, also called a grid-tie inverter, is a solar inverter that converts DC output from rooftop panels into AC and feeds it into the house wiring and the utility grid, with no battery in the system. It is the cheapest and most common architecture in Indian residential rooftop solar because it removes the most expensive component, the battery, entirely.
The design assumption is that the grid is always there. An on-grid inverter synchronises its output to the grid’s voltage and frequency and uses the grid as its reference signal. Surplus generation is exported and credited under net metering, and at night the house draws from the grid as normal.
That assumption decides everything else. When the grid disappears, the reference signal disappears with it.
Why Your On-Grid Solar Inverter Shuts Down the Moment the Grid Fails
An on-grid solar system produces no power during a power cut because the inverter is legally and electrically required to disconnect. The panels continue to generate DC. The inverter refuses to convert it.
The reason is a safety condition called unintended islanding. The CEA connectivity regulations define an unintended island as a part of the electricity system “which remains energised by one or more distributed generation resource, when such part of the system has been isolated from the remaining part of the electricity system.”
Picture the sequence. A distribution fault takes the local feeder down and a lineman is dispatched, treating the line as dead because the utility switched it off. If a rooftop inverter three houses away kept pushing power onto that feeder, the line would be live and the lineman would have no way of knowing.
The second hazard is equipment damage. In an island, voltage and frequency are held up by the inverter alone, with no grid to stabilise them. Motors, compressors and electronics on that segment can see conditions well outside their rated band.
An on-grid solar inverter that kept running during an outage would energise a line that utility staff have been told is dead, which is why every grid-tie inverter sold in India is built to shut down instead.
What Indian Regulation Requires: Two Seconds Out, Sixty to Come Back
The Central Electricity Authority (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations, 2013, amended in February 2019, govern every rooftop solar connection below 33 kV in India. That covers all residential systems without exception.
Four provisions in Regulation 11(6) decide what your inverter does during a disturbance:
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Anti-islanding, Regulation 11(6)(e). The system must have a function preventing it from contributing to an unintended island, and must cease to energise the electricity system within two seconds of that island forming. Two seconds is the outer limit, and most inverters act faster.
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Reconnection delay, Regulation 11(6)(d). A voltage and frequency sensing and time-delay function must prevent the system from energising a dead circuit, and must block reconnection until voltage and frequency are within limits and stable for at least sixty seconds. This is why solar output does not return the instant the lights come back.
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Voltage trips, Regulation 11(6)(a). Over and under voltage trip functions operate if voltage reaches above 110% or falls below 80%, with a clearing time of up to two seconds. The distribution licensee is permitted to prescribe a narrower band.
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Frequency trips, Regulation 11(6)(b). Over and under frequency trip functions operate at 50.5 Hz and below 47.5 Hz, with a clearing time of up to 0.2 seconds. Again, the licensee may set tighter limits locally.
Point 3 matters more than most buyers expect. Indian supply does not fail cleanly. It sags, swings and browns out, and an on-grid system will trip on a deep voltage sag even when the grid has not gone away entirely.
None of this is a manufacturer choice or a quality difference between brands. An inverter without these functions cannot be legally connected.
On-Grid vs Off-Grid vs Hybrid Solar Inverter: What Each One Does During an Outage
| On-grid (grid-tie) | Off-grid | Hybrid | |
|---|---|---|---|
| Battery | None | Required | Required, usually LiFePO4 |
| Works during a power cut | No | Yes | Yes, on the backed-up circuit |
| Exports surplus to grid | Yes, under net metering | No | Yes, where the DISCOM permits |
| Needs grid to operate | Yes | No | No |
| Upfront cost | Lowest | Highest per usable unit | Between the two |
| Best suited to | Areas with very reliable supply, bill reduction only | Sites with no grid connection at all | Indian homes wanting both bill reduction and backup |
The distinction that matters is not solar versus no solar. It is whether the system can operate disconnected from the grid.
A hybrid inverter can supply your home during an outage because it isolates the house circuit from the grid first, then runs as its own source. It is not islanding the utility network, it is powering a circuit that has been separated from it. That separation is what makes backup operation legitimate where a grid-tie inverter’s would not be.
Truepower’s KIVO Hybrid Solar Inverter range is built for this architecture, scaling from 3.6kW to 12kW with MPPT charge control. The trade-off is honest: a hybrid system costs more than an equivalent on-grid system because it carries a battery and the electronics to manage three power sources instead of one. The detailed case for that architecture is covered in our guide on how a hybrid solar inverter cuts your electricity bill.
What the PM Surya Ghar Subsidy Actually Pays For
PM Surya Ghar: Muft Bijli Yojana is the central government scheme supporting grid-connected rooftop solar for residential households, launched on 13 February 2024 with a total outlay of Rs 75,021 crore. According to the Ministry of New and Renewable Energy, beneficiaries receive a subsidy of up to Rs 78,000 for a rooftop system of up to 3 kW.
The scheme also provides collateral-free loans through 12 public sector banks at 6.75% for amounts up to Rs 2 lakh. As of 10 March 2025, MNRE reported 10.09 lakh completed installations and over 3 GW of rooftop capacity under the scheme.
Read the subsidy for what it is. It supports a grid-connected system that reduces your electricity bill. It is not a backup subsidy, and a household that installs a 3 kW on-grid system expecting the lights to stay on during a cut has bought the wrong thing for that need.
If you intend to add storage, confirm the treatment with your DISCOM before commissioning, because net metering approval runs through the distribution licensee and storage handling is not uniform across states.
How Much Backup an Indian Home Actually Needs
Grid reliability in India has improved substantially, and it is still not good enough to design a house around.
CEEW’s India Residential Energy Survey, conducted in 2019 across roughly 15,000 households in 152 districts and 21 states, found that the average Indian household received 20.6 hours of grid supply a day, 22 hours urban and 20 rural. 76% faced unanticipated supply interruptions, and two-thirds of rural and two-fifths of urban households faced outages at least once a day. Rural households in Uttar Pradesh, Jharkhand, Haryana, Assam and Bihar faced six or more hours of daily outages.
Those figures are from 2019 fieldwork and supply hours have risen since, so treat them as a floor rather than a current reading. The structural point holds: outages in India cluster in the evening and at peak demand, which is precisely when a rooftop array produces little or nothing.
That timing is the argument against solving backup with panels alone. Even a system that could legally run islanded would give you very little at 8pm in July. Backup is a stored-energy problem, not a generation problem.
How to Decide Between On-Grid and Hybrid for Your Home
Work through these in order.
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Count your outages honestly for one month. Note duration and time of day. A household losing supply for twenty minutes twice a month has a different problem from one losing four hours every evening. In the first case an on-grid system plus modest essentials backup is sensible. In the second, backup is the primary requirement and solar is secondary.
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Separate the two goals before you price anything. Bill reduction and outage cover are different jobs. An on-grid system does the first and none of the second. Deciding which you actually care about prevents the most common and most expensive mistake in this category.
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Size the backed-up circuit, not the whole house. Essentials backup usually means fans, LED lighting, a television, a router and a refrigerator. Our guide on choosing the right inverter capacity covers the VA and watt-hour arithmetic, and the short version is that VA decides how much runs at once while watt-hours decide how long.
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Decide whether solar is coming within two years. If it is, a hybrid unit bought now is considerably cheaper than replacing a non-solar inverter later. If solar is genuinely not in the plan, a dedicated lithium inverter is the simpler and cheaper answer. The Lithvon lithium inverter range spans 700VA to 5kVA across 12V, 24V and 48V systems for exactly this case.
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Confirm interconnection requirements with your DISCOM before you buy. The CEA regulations set the national floor, but Regulation 11(6) expressly allows a distribution licensee to prescribe narrower voltage and frequency bands, and the licensee carries out the interconnection study that determines what is permitted at your location.
Frequently asked questions
- Does an on-grid solar system work during a power cut?
- No. An on-grid solar inverter shuts down within two seconds of the grid failing and produces nothing until supply is restored and stable. This is required by Regulation 11(6)(e) of the CEA (Technical Standards for Connectivity of the Distributed Generation Resources) Regulations, 2013, which obliges a grid-connected system to cease energising the electricity system within two seconds of an unintended island forming. The panels keep generating DC throughout, but the inverter will not convert it, because doing so would energise a distribution line that utility personnel have been told is dead. If you want power during outages you need a hybrid inverter with a battery, or a separate battery inverter on an essentials circuit.
- Why does my solar not come back immediately after the power returns?
- Because the regulation blocks it. Regulation 11(6)(d) requires a voltage and frequency sensing and time-delay function that prevents reconnection until voltage and frequency are within prescribed limits and have been stable for at least sixty seconds. Sixty seconds is the national minimum and your distribution licensee is permitted to set a longer or narrower requirement, so a restart delay of a minute or more after supply returns is normal behaviour rather than a fault. If supply is unstable and swinging in and out, the inverter will keep waiting for a clean sixty-second window before it reconnects.
- Can I add a battery to an existing on-grid solar system?
- Sometimes, but it is rarely the cheapest route. Retrofitting storage to a grid-tie system generally means adding an AC-coupled battery inverter alongside the existing unit, or replacing the grid-tie inverter with a hybrid one. Both cost more than choosing the hybrid architecture at the outset. Net metering and interconnection also run through your distribution licensee, so confirm any change to the installed configuration with them before work starts.
- Is a grid-tie inverter shutting down a fault or a defect?
- Neither. It is the inverter doing exactly what Indian law requires. Anti-islanding is not a feature that varies by brand or price point, it is a mandatory protective function under Regulation 11(6)(e) for every distributed generation resource connected below 33 kV. An inverter without that function cannot legally be connected to the grid in India. If a seller offers you a grid-tie inverter that they claim will run during outages without a battery, treat that as a reason to walk away.
- Why does my on-grid system trip even when the power has not gone off?
- Because voltage and frequency excursions trip it too. Regulation 11(6)(a) sets over and under voltage trips above 110% and below 80% with a clearing time of up to two seconds, and Regulation 11(6)(b) sets frequency trips at 50.5 Hz and below 47.5 Hz with a clearing time of up to 0.2 seconds. A deep voltage sag on a weak feeder will cross that threshold without the supply failing outright. Distribution licensees are also permitted to prescribe narrower bands than the national floor, so local settings may be tighter than these numbers suggest.
- Is on-grid or hybrid better for an Indian home?
- It depends on which problem you are solving. On-grid is the cheapest way to cut an electricity bill and is reasonable where supply is genuinely reliable and outages are rare and short. Hybrid costs more because it carries a battery and manages solar, grid and storage together, and it is the architecture that keeps a backed-up circuit live during a cut. CEEW’s 2019 survey found 76% of Indian households experiencing unanticipated interruptions, so most homes buying rooftop solar are doing so where the grid is not dependable, which is the case for hybrid.
Speak to the Truepower Team
Truepower designs inverter and lithium storage systems for Indian supply conditions, including the KIVO Hybrid Solar Inverter range for solar homes and the Lithvon lithium inverter range for essentials backup. Full specifications for every series are on the Truepower resources page, and you can reach the team through the contact page.
For the storage side of the decision, see our complete buyer’s guide to lithium inverters for home and the lithium inverter price breakdown from 1000VA to 5000VA.