Every rooftop solar installation in India — regardless of size, state, or whether it is subsidised — requires DISCOM approval before the system can be legally connected to the grid and before net metering credits can start accumulating.
DISCOMs (Distribution Companies) are the ground-level implementing agencies. They check technical feasibility, issue the connection sanction, conduct the commissioning inspection, and install the net meter. The process varies by state, but the underlying stages are consistent.
The Role of DISCOMs in India’s Solar Ecosystem
DISCOMs are not just the last mile in electricity distribution — they are the primary approving authority for every grid-connected solar installation. The SERC sets the rules; the DISCOM enforces them.
For a solar installer, the DISCOM relationship determines:
- Whether the project gets approved at the proposed system size
- How long the process takes from application to net meter activation
- What documentation format is accepted
- Whether the PM Surya Ghar commissioning report gets uploaded (which triggers subsidy)
DISCOM performance varies dramatically across states and even across different sub-divisions of the same DISCOM. Understanding how to navigate your specific DISCOM’s process is a commercial advantage.
Required Documents for DISCOM Application
| Document | Purpose | Notes |
|---|---|---|
| Electricity consumer account number | Identifies the connection and sanctioned load | On the electricity bill |
| Load sanction letter | Confirms permitted connected load (kW) | May need to be freshly obtained for older connections |
| Site plan | Shows rooftop layout and proposed panel placement | Google Maps-extracted or hand-drawn accepted by most DISCOMs |
| Single-line diagram (SLD) | Electrical schematic from panels to grid | Must include inverter model, string config, protection details |
| Inverter datasheet + IS 16221 BIS cert | Confirms inverter compliance | Model-specific BIS certificate |
| Module datasheet + IS 14086 BIS cert | Confirms module compliance | Model-specific BIS certificate |
| ALMM compliance declaration | Required for PM Surya Ghar | Signed installer declaration |
| Proof of ownership / landlord NOC | Confirms right to install | Sale deed, property tax receipt, or NOC |
| Application fee | Varies by DISCOM | Demand draft or online payment |
Load Sanction Letter: The Most Commonly Missing Document
Many older residential connections — particularly in semi-urban and rural areas — do not have a formal load sanction letter. Customers need to request this separately from the DISCOM’s commercial department. This can add 15–30 days to the process if not identified early. Check for this document during the initial site visit, not after the customer has applied.
The DISCOM Feasibility Study
The feasibility study is the DISCOM’s internal technical check. It answers one question: does the local distribution infrastructure have capacity to absorb this solar installation’s export?
What the DISCOM checks:
- Transformer loading: Is the distribution transformer serving this consumer below its rated capacity?
- Feeder loading: Can the feeder handle reverse power flow (solar export) during peak generation periods?
- Voltage profile: Will the export cause voltage rise that pushes other consumers’ voltages above acceptable limits?
Outcomes:
| Outcome | Meaning | Next Step |
|---|---|---|
| Full sanction | Approved at requested system size | Proceed with installation |
| Reduced sanction | Approved at smaller size | Redesign or accept smaller system |
| Deferral | Transformer upgrade pending | Wait (timeline unclear); escalate if extended |
| Rejection | Feeder/transformer fully saturated | Option: export limiting with monitoring system |
Transformer Saturation in Dense Urban Areas
In premium residential localities of Bangalore (BESCOM), Pune (MSEDCL), and Ahmedabad (UGVCL), distribution transformers in some areas are approaching 100% solar penetration limits. DISCOMs in these areas are increasingly capping approved system sizes well below the consumer’s sanctioned load. Identify this risk before quoting large systems in these areas — request informal feeder loading information from the DISCOM before submitting the formal application.
Typical Timelines by State
| State | DISCOMs | Application Portal | Feasibility Sanction | Net Meter (post-commissioning) |
|---|---|---|---|---|
| Gujarat | UGVCL, MGVCL, PGVCL, DGVCL | Online | 15–25 days | 20–35 days |
| Karnataka | BESCOM, GESCOM, etc. | BESCOM online; others manual | 15–30 days | 25–45 days |
| Maharashtra | MSEDCL, Tata Power, Adani | MSEDCL online | 20–35 days | 30–50 days |
| Tamil Nadu | TANGEDCO | Online | 20–40 days | 30–50 days |
| Rajasthan | AVVNL, JVVNL, JdVVNL | Partial online | 25–45 days | 30–60 days |
| Punjab | PSPCL | Online | 20–40 days | 30–60 days |
| Uttar Pradesh | PVVNL, DVVNL, MVVNL, etc. | Online | 30–60 days | 45–90 days |
| Madhya Pradesh | MPEZ, MPMKVVCL, MPWZ | Partial online | 30–60 days | 45–90 days |
Timelines are indicative and vary by sub-division, season, and application backlog.
Net Meter Installation: What Happens and When
After the DISCOM’s commissioning inspection, the net meter installation is the final technical step before the system is fully operational on the grid.
The net meter is a bidirectional energy meter that records:
- Import register: units consumed from the grid
- Export register: units exported to the grid
The net metering credit calculation is based on: Net consumption = Import register − Export register
Who installs it: The DISCOM, through its own meter team or contracted metering agency.
Who pays: The consumer. Typical cost: Rs. 2,000–Rs. 8,000 depending on DISCOM and meter type.
Timeline: 15–90 days from commissioning inspection, depending on DISCOM and meter availability. This is often the longest single delay in the process.
Pro Tip: Track Meter Installation Status Separately
Net meter installation is often handled by a different DISCOM department from the sanction team. After commissioning inspection, escalate meter installation requests to the DISCOM’s metering section directly — do not assume the inspection team has handed it off automatically. Following up weekly after inspection is standard practice for experienced installers.
The Connection Agreement
After the DISCOM issues technical sanction, the consumer typically signs a net metering connection agreement (or grid interconnection agreement) with the DISCOM. This document covers:
- The approved system capacity
- Export rate (APPC as per current SERC tariff order)
- Settlement period (monthly or annual)
- Consumer’s obligations (maintaining system, providing DISCOM access for inspection)
- DISCOM’s obligations (meter installation, billing, export credit calculation)
- Termination conditions
The agreement is the legal basis for the net metering relationship. Retain a copy for the consumer’s records.
Empanelled Vendors vs Independent Installers
For PM Surya Ghar projects, only empanelled vendors can manage the full DISCOM workflow through the national portal. The DISCOM will only process commissioning reports submitted by registered vendors.
For non-subsidised commercial and industrial installations, independent licensed electrical contractors can apply directly. They need:
- Licensed electrical contractor registration (state electrical licensing authority)
- Standard DISCOM application with all required technical documentation
- No requirement for pmsuryaghar.gov.in registration
The technical documentation requirements — single-line diagram, BIS certificates, IS 14086/IS 16221 compliance, earthing test records — apply equally to both empanelled and independent installer submissions.
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Common Rejection and Delay Causes
Transformer at capacity: The single most common cause. Affects dense residential localities in major cities. No workaround without transformer augmentation by the DISCOM.
Incomplete SLD: The single-line diagram missing required details (protection relay symbols, inverter model, string configuration). Use solar design software that generates compliant SLDs to avoid this.
Missing load sanction letter: Consumer’s older connection lacks this document. Needs a separate request from DISCOM commercial department — takes 15–30 days.
Non-ALMM component: For PM Surya Ghar, if any component is not on the current ALMM list at commissioning time, the report cannot be submitted through the portal.
BIS certificate mismatch: BIS certificate number on the submitted datasheet does not match the BIS database for that model number. Happens when manufacturers update model variants without corresponding BIS update.
Ownership documentation gap: Applicant lives in jointly owned property, rented property, or apartment without clear ownership proof.
Frequently Asked Questions
How long does DISCOM approval take?
15–30 days for technical sanction in well-run states like Gujarat and Karnataka. 45–90 days in states with manual processes or high backlogs. Net meter installation after commissioning adds another 15–90 days.
What documents are required?
Load sanction letter, site plan, single-line diagram, module and inverter BIS certificates, ALMM declaration (for PM Surya Ghar), proof of ownership, and application fee.
Can an independent installer apply without empanelment?
For PM Surya Ghar: no. For private commercial/industrial projects without central subsidy: yes, with standard licensed contractor documentation.
Who pays for the net meter?
The consumer pays — typically Rs. 2,000–Rs. 8,000. The DISCOM procures and installs it.
What is the feasibility study?
The DISCOM’s check on whether the local distribution transformer has capacity for the proposed solar export. Failure or reduction of capacity is the most common approval issue in dense urban areas.
