Choosing an inverter for PM Surya Ghar

Short answer: for a standard 3 kW PM Surya Ghar home on a single phase connection, a 3 kW single phase on-grid inverter is the usual match. Choose a hybrid inverter instead if the home needs backup during power cuts.

What the subsidy covers

Under PM Surya Ghar: Muft Bijli Yojana, the central financial assistance (CFA) for a home is calculated on the solar panel capacity, not the inverter:

• ₹30,000 per kW for the first 2 kW
• ₹18,000 for the third kW
• a maximum of ₹78,000 for systems of 3 kW and above

The panels must be DCR (made with Indian cells). The application is made on the national portal, pmsuryaghar.gov.in, and your DISCOM handles the feasibility check, net meter and inspection. In Bihar that is North Bihar Power Distribution Company (NBPDCL) or South Bihar Power Distribution Company (SBPDCL); in Jharkhand it is JBVNL.

In July 2026 the Bihar Electricity Regulatory Commission waived the application fee and meter testing charges for domestic rooftop systems under PM Surya Ghar, which lowers the upfront cost for homes in Bihar.

Sizing the inverter

Match the inverter to the panel capacity. A 3 kW array normally goes with a 3 kW inverter; some installers use 3.6 kW to leave room for slightly more panel wattage. Polycab's single phase on-grid range comes in eight sizes from 2 to 6 kW, so you can size closely without paying for capacity you don't use.

Check the panel string against the inverter's limits: the Polycab PSIS single phase models take up to 20 A input current and 500 V (2–3.6 kW) or 600 V (4–6 kW) DC. With today's 540–600 Wp panels, a 3 kW system is typically 5 or 6 panels in a single string.

Single phase or three phase?

Most homes in Bihar and Jharkhand have a single phase connection, so a single phase inverter is the default. If the home has a three phase meter and a system of 5 kW or more, use a three phase inverter (Polycab PSIT 5–10 kW) so the export is spread across the phases. Your DISCOM may have its own rules on the maximum single phase capacity; check before you finalise.

Certification to check

For a grid-connected system, ask for the inverter's BIS registration. Polycab's catalogue lists IS 16169:2014 (anti-islanding) and IS 16221 (Part 2):2015 (safety) for its single phase on-grid series. DISCOMs may also have their own requirements for inverters connected to their network, so confirm with NBPDCL, SBPDCL or JBVNL during the application.

Local conditions that matter

• Heat: rooftops in Patna and Gaya regularly pass 45 °C in summer. Mount the inverter in shade with airflow; Polycab inverters are rated to operate up to 60 °C.
• Dust and monsoon: choose an IP65 or IP66 enclosure. Polycab single phase on-grid inverters are IP65, three phase and hybrid models are IP66.
• Voltage swings: rural feeders can see wide voltage variation. A wide AC operating range keeps the inverter generating instead of tripping.
• Power cuts: an on-grid inverter switches off when the grid goes down. If the customer expects solar power during cuts, quote a hybrid system.

Quick checklist

Scheme rules and DISCOM procedures change. Check the latest guidelines on the PM Surya Ghar portal and with your DISCOM before you install. This guide is general information, not legal or financial advice.