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BIS Certification for Liquid Immersed Distribution Transformers IS 1180: Part 3: 2021

Distribution transformers play a vital role in the electrical power distribution network, ensuring efficient and safe voltage conversion for end users. Among the many types of transformers, those immersed in natural or synthetic organic ester liquids have gained prominence due to their enhanced fire safety, biodegradability, and superior insulation properties.

To ensure the quality, safety, and reliability of these transformers in the Indian market, the Bureau of Indian Standards (BIS) has mandated conformity to IS 1180: Part 3: 2021. This standard specifies the requirements for liquid-immersed distribution transformers up to and including 2500 kVA and 33 kV, using natural or synthetic organic ester liquids as the insulating medium.

About IS 1180: Part 3: 2021

The Indian Standard IS 1180: Part 3:2021 lays down comprehensive requirements for distribution transformers that use environmentally friendly insulating liquids. These transformers are designed to deliver high performance while minimizing risks related to flammability and environmental contamination.

The standard ensures that transformers maintain a high degree of electrical efficiency and safety under varying load and environmental conditions. It includes design, performance, and testing parameters that manufacturers must comply with to qualify for BIS certification.

Why BIS Certification Matters

BIS certification under IS 1180: Part 3 ensures that transformers are:

● Technically compliant with Indian safety and performance benchmarks

● Manufactured under controlled and audited conditions

● Reliable in diverse and demanding operational environments

● Eligible for public procurement and government tenders

● Trusted by utility providers and large-scale infrastructure developers

With an increasing focus on fire-safe, sustainable infrastructure, BIS certification for ester-immersed transformers is becoming indispensable in both urban and rural electrification projects.

Tests Performed During BIS Certification

Transformers covered under IS 1180: Part 3: 2021 undergo a series of critical tests to verify their performance, insulation, durability, and safety. These include:

● Determination of Sound Levels: Ensures that operational noise remains within acceptable limits, crucial for residential and commercial settings.

●Short-Circuit Withstand Test: Verifies the transformer's ability to withstand mechanical and thermal stresses during short-circuit conditions.

● No-Load Current Measurement: Evaluates the magnetizing current and associated core losses when the transformer is energized without any load.

● Paint Adhesion Test: Ensures the paint and coatings on the transformer body are durable, resistant to peeling, and protect against corrosion.

● Breakdown Voltage (BDV) and Moisture Content of Liquid: Assesses the dielectric strength and insulation properties of the ester liquid used, ensuring it meets safety standards.

● Destructive Test (Maximum Flux Density): Determines the core’s magnetic saturation point to avoid excessive heating or performance degradation.

● Minimum Clearances in Air: Confirms the required physical distances between conductive parts to prevent arcing and ensure operational safety.

These tests, conducted either at BIS-approved labs or in accredited manufacturing facilities, form the technical backbone of the certification process.

BIS Certification Process

Though BIS certification is a technical process, the core steps remain structured and straightforward:

Application Submission: The manufacturer applies to BIS with product details and relevant documentation.

Factory Audit: BIS officials inspect the manufacturing unit to assess quality control systems and production capabilities.

Sample Testing: Product samples are drawn and sent for testing to evaluate compliance with IS 1180: Part 3: 2021.

Grant of License: Upon satisfactory audit and test results, BIS issues the ISI mark license for the product.

Ongoing Surveillance: Periodic inspections and testing ensure continued compliance with BIS standards.

To Know The Process in Detail, Please Visit:

BIS ISI Mark Certification for Domestic Manufactures
BIS ISI Mark Certification for Foreign Manufactures

Under BIS Registration Products ISI and CRS

BIS CRS Registration For IT Products List
BIS ISI Mark Certification For ISI Products List

Documents Required for BIS Certification

To apply for BIS certification, manufacturers need to submit the following documents:
●  Application form
●  Manufacturing process details
●  Quality control plan
●  Test reports from BIS-approved laboratories
●  Factory layout and equipment details
●  Proof of business registration
●  Product specifications and technical details
●  Declaration of conformity to Indian standards
Additionally, manufacturers may be required to provide proof of compliance with environmental and safety regulations, depending on the specific type of product being certified.

BIS ISI Mark Certification Costing And Timeline

How EVTL India Supports Your BIS Certification Journey

EVTL India, a premier regulatory compliance consultancy, specializes in helping transformer manufacturers navigate the BIS certification process efficiently. With deep domain knowledge and a hands-on approach, EVTL India offers:

● End-to-end support from documentation to product testing

● Assistance with application preparation and audit readiness

● Coordination with BIS labs and officials for faster processing

● Expert guidance on compliance requirements for IS 1180: Part 3: 2021

Whether you're a domestic manufacturer or an international exporter looking to enter the Indian market, EVTL India ensures a smooth and compliant certification process, minimizing delays and maximizing market opportunities.

Conclusion

With the shift towards sustainable and safe electrical infrastructure, BIS certification for ester-immersed distribution transformers up to 2500 kVA and 33 kV is no longer optional—it’s essential. Adhering to IS 1180: Part 3: 2021 not only ensures legal compliance but also boosts product credibility, opens new business avenues, and builds trust among end users.