IS 16221: India Solar Inverter Safety Standard

Definition

IS 16221 is the Indian Standard for safety of solar PV inverters, aligned with international IEC 62109. Required for BIS certification and ALMM List II listing in India.

Key Takeaways

IS 16221 = Indian inverter safety standard.
Equivalent to IEC 62109.
Companion to IS 16170 (performance).
Required for ALMM listing.
Inverters certified under both for grid-tied solar.

What IS 16221 Actually Covers

IS 16221 is a safety standard, not a performance one — it addresses how an inverter protects installers, technicians, and building occupants from electric shock, fire, and overheating rather than how efficiently the inverter converts DC to AC. That distinction matters when reading a datasheet: an inverter’s IS 16221 mark speaks to enclosure protection, insulation resistance, and fault-clearing behavior, while its IS 16170 mark speaks to conversion efficiency and grid-code compliance. Both certifications sit under the same BIS umbrella and are usually earned together, since a manufacturer testing a model for one standard typically submits it for the other in the same certification cycle.

Where IS 16221 Fits in the Compliance Chain

For a project team, IS 16221 rarely appears as a standalone checkpoint — it surfaces indirectly, through the equipment list. A DISCOM or CEIG reviewer checking a net metering or interconnection application generally confirms that the specified inverter model carries a valid BIS mark against IS 16221 and IS 16170, and that the same model appears on the ALMM List II if the project is government-subsidized or DCR-mandated. Specifying an inverter that hasn’t completed IS 16221 certification — common with newer models entering the Indian market — is one of the more avoidable reasons a permit package gets sent back for equipment substitution late in the review cycle.

Since IS 16221 sits inside the broader BIS certification framework for solar equipment, our glossary entry on BIS Solar walks through how IS 16221 relates to the other IS standards (modules, cables, earthing) that make up a complete compliance package. For the state-by-state view of how equipment certification gaps affect approval timelines in practice, see Solar Permits India: State-Wise Processing Times 2026. On the manufacturer side, Qbits Energy’s breakdown of solar inverter regulatory compliance in India and its IEC 62109 glossary entry go deeper into the international standard that IS 16221 is modeled on.

Frequently Asked Questions

6 commonly searched questions about IS 16221.

What is IS 16221?

IS 16221 is the Bureau of Indian Standards (BIS) specification covering the safety requirements of solar PV inverters — protection against electric shock, fire, and mechanical hazards. It is India's national adoption of IEC 62109, the international inverter safety standard.

How is IS 16221 different from IS 16170?

IS 16221 governs inverter safety (shock, fire, insulation, enclosure protection). IS 16170 governs inverter performance (efficiency, power quality, grid behavior). Both standards are companions — a grid-tied inverter sold in India needs to satisfy both to be BIS-certified and ALMM List II eligible.

Is IS 16221 mandatory for solar inverters sold in India?

Yes, for grid-connected inverters used in BIS-certified and ALMM-listed projects. BIS certification against IS 16221 is a prerequisite for ALMM List II listing, and DISCOMs typically verify BIS marks before granting net metering or interconnection approval.

Is IS 16221 the same as IEC 62109?

IS 16221 is India's national-standard adaptation of IEC 62109, so the two are closely aligned in scope and test methodology. Manufacturers who already hold IEC 62109 certification generally have a shorter path to IS 16221 BIS certification, though the BIS process still requires testing through an accredited Indian lab.

Why does ALMM listing require IS 16221?

ALMM List II (inverters) requires BIS certification, and IS 16221 is the safety component of that certification (alongside IS 16170 for performance). Without an IS 16221-certified inverter, a project cannot use that inverter model on ALMM-mandated government or subsidized installations.

Who checks IS 16221 compliance on a project?

BIS certifies the inverter model itself, not individual installations. On a project, DISCOMs and CEIG offices typically confirm that the specified inverter carries a valid BIS mark against IS 16221 (and IS 16170) during net metering or electrical clearance review, rather than testing the unit on site.