Current Transformer Certifications Explained: A Buyer's Guide to Accuracy, Standards, and Compliance

Current transformer certification is not a single document, but a layered system of product standards, metrological verification, and market-specific declarations. For procurement teams evaluating current transformers for energy metering, EV charging, solar inverters, or smart grid projects, the practical question is not “is it certified,” but “which certification applies to the product, the market, and the application.” This guide explains the main certification types, how they map to current transformer families, and what buyers should verify before supplier selection.

Why Current Transformer Certification Matters in Sourcing

Current transformers are measurement components that feed data into revenue meters, protection relays, and monitoring systems. A certification gap can lead to rejected shipments, failed grid inspections, or inaccurate billing. The IEC 61869-2 standard, which replaced IEC 60044-1 for inductive current transformers, defines accuracy classes such as 0.5 and 0.5S and serves as the core international reference for instrument transformer performance. Buyers increasingly use certifications as a shortlist filter, not just a compliance checkbox.

From a procurement perspective, certifications serve three functions. First, they verify that the transformer meets a recognized safety or performance baseline. Second, they indicate which market the product can legally enter. Third, they support specific applications such as utility billing, where revenue grade accuracy below 0.5 is often required.

Key Certification Types for Current Transformers

Several certification categories appear repeatedly in current transformer datasheets. Understanding the differences helps buyers avoid confusing a material compliance document with a product safety certificate.

CE-LVD (2014/35/EU)

The Low Voltage Directive covers electrical equipment safety. For current transformers, CE-LVD certification is typically issued against EN 61869-1 and EN 61869-2 or IEC 61869-2:2012. It confirms that the transformer has been assessed for basic safety risks in low-voltage installations. Multiple HEYI current transformer families carry CE-LVD certification, including split-core, CP, MSQ, and busbar split-core models, with certificates issued by testing bodies such as Shenzhen Easy Test Electronic Products Co., Ltd., Beide (Shenzhen) Product Service Limited, and TÜV SÜD Product Service GmbH.

CE-EMC (2014/30/EU)

Electromagnetic compatibility certification verifies that the device operates without causing or suffering from unacceptable electromagnetic interference. The busbar split-core current transformer (DP/HK) holds CE EMC certification under certificate B-E2505D2378, issued by Beide (Shenzhen) Product Service Limited, conforming to EN IEC 61000-6-3:2021 and EN IEC 61000-6-1:2019.

RoHS (2011/65/EU & (EU) 2015/863)

RoHS restricts hazardous substances in electrical and electronic equipment. Although RoHS is often grouped with other certifications, it does not verify measurement performance. It verifies material composition. HEYI split-core, KCD, MSQ, and DP/HK models have RoHS coverage through bodies such as Shenzhen LCS Compliance Testing Laboratory Ltd., Ningbo LCS Standard Technology Service Co., Ltd., and SGS, referencing the IEC 62321 series.

UKCA

The UK Conformity Assessed marking covers products placed on the United Kingdom market. The KCT and KCT-L split-core current transformers hold UKCA certification number CLZJ23072649108, issued by Shanghai Global Testing Services Co., Ltd., conforming to BS EN 61869-2:2012.

Type Test Reports (IEC 61869 Series)

Type tests validate the design of a transformer against the relevant standard. The RECT revenue-grade current transformer is covered by Type Test Report 25T0221-S, issued by Suzhou Electrical Apparatus Science Research Institute Co., Ltd., compliant with the IEC/EN 61869 series. The outdoor current transformer (model LMZW) is covered by Type Test Report 25133Z40179, issued by Zhejiang Fangyuan Test Group Co., Ltd., conforming to IEC 61869-1 and IEC 61869-2.

Metrological Verification and Calibration

Metrological certificates differ from type tests. They verify that a specific unit or test system delivers accurate measurement. HEYI holds metrological verification certificate D20250900173 for a Standard Current Transformer with Current Booster (Model HLS21-2S, Ratio 5A/5A–2000A/5A), issued by Yueqing Institute of Quality and Technical Supervision Inspection, in accordance with JJG 313-2010. Calibration certificates for test equipment used in production include D20250900172 and D20250900171 (JJF 1264-2010) and D20250900170 (JJG 795-2016). These certificates support the company’s internal quality control rather than a single product family.

Ingress Protection (IP65)

For outdoor current transformers, enclosure protection matters. The OCT outdoor waterproof split-core current transformer holds an IP65 rating certification under certificate Qst-23N020111-1SR, issued by Shenzhen Qstlab Testing Co., Ltd., conforming to IEC 60529:1989+A1:1999+A2:2013.

HEYI Electrical: Company Profile and Certification Approach

Wenzhou HEYI Electrical Co., Ltd. (HEYI) is a manufacturer established in 2012, specializing in current transformers, current sensors, shunts, digital energy meters, and current transmitters. The company operates a 10,000 m² facility with 56 employees and 5 R&D engineers, producing approximately 356,000 units per year. Around 95% of output is exported to Southeast Asia, South Korea, Europe, South America, Australia, Africa, the Middle East, and North America. HEYI serves OEM and ODM customers and reports that its engineering is trusted by companies including Siemens, Schneider Electric, LG, Samsung, and SoftBank, as well as national telecom operators and utility providers.

HEYI’s quality management system for the production of low-voltage current transformers is certified to ISO 9001:2015 under certificate 20224Q21295R0S, valid until 2027-11-20. The company’s certification portfolio spans EU, UK, China, and global markets, which is relevant for buyers managing multi-region product launches.

Mapping HEYI Product Families to Certifications and Applications

Different current transformer families serve different applications. Certification coverage also varies by model, so buyers should match both technical specs and compliance documents to the target market.

Split-Core Current Transformers (KCT, KCD, KCT-L)

Split-core designs allow installation without disconnecting the primary conductor, which makes them practical for retrofit projects. The KCT series covers measurement from 0 to 1000 A with accuracy classes 3.0, 1.0, and 0.5, and offers outputs of 5 A, 1 A, mA, mV, RS485, or 4-20 mA. The KCD is a smart split-core current transformer with RS485 communication and 4-20 mA output, accuracy 1.0, and 0 to 50 mm inner diameter. Its stated applications include Beijing/Hangzhou Metro Lines, elevator monitoring, green buildings, O&M services, and smart factory retrofits. The KCT-L is a True RMS current transformer/transmitter with 4-20 mA output for PLC/DCS integration and remote power monitoring.

Certification coverage for the KCT family includes CE-LVD (ET16118324-LVD), RoHS (GST.210923.S201R and LCSE03115005R), and UKCA (CLZJ23072649108). The KCD is RoHS certified under 2011/65/EU and (EN)2015/863. The KCT-L holds UKCA certification under the same certificate as KCT.

Busbar Split-Core Current Transformers (DP/HK)

Busbar split-core transformers are designed for large busbar installations in switchgear panels and industrial energy monitoring. The DP/HK series measures up to 8000 A with an inner diameter up to 80×160 mm. The DP/HK model holds CE EMC certification (B-E2505D2378) and RoHS certification (SHAEC2123838801).

Outdoor Current Transformers (OCT, LMZW)

The OCT is an outdoor waterproof split-core CT for overhead line monitoring, outdoor solar and wind, municipal infrastructure, and railway trackside applications. It measures up to 8000 A with IP65 protection and holds IP65 certification under Qst-23N020111-1SR. The LMZW is an outdoor resin-cast current transformer for marine and offshore, chemical and metallurgy, and RMU applications. It is covered by Type Test Report 25133Z40179 (IEC 61869-1 and IEC 61869-2).

Revenue-Grade Current Transformers (RECT)

The RECT is an extended range current transformer (ERCT) designed for utility and substation billing, utility-scale solar and wind plants, data center sub-billing, and premium meter OEM manufacturing. It offers 0.15S high accuracy, complies with IEEE C57.13, and is anti-saturation. The transformer provides 5 A or 1 A secondary output, measurement range 0 to 1000 A, inner diameter 0 to 78 mm, IP65 protection, and UV resistance. It is covered by Type Test Report 25T0221-S (IEC/EN 61869 series).

Three-Phase Current Transformers (DASN)

The DASN is a 3-phase integrated CT for main and branch monitoring, UPS, MCCs, smart buildings, IDC and telecom, and EPC solar/wind/storage projects. It measures 0 to 1000 A with accuracy 1.0 and output 5 A. Certification coverage for the DASN model is not listed in the provided corpus, so buyers should request the relevant declaration before specifying it for CE-marked equipment.

Residual Current Sensors (HYCA)

The HYCA is a residual current sensor for EV charging infrastructure and solar/wind/energy storage applications. It is classified as a 6 mA DC leakage current sensor and RDC-PD (residual direct current protective device). It detects differential current from 0 to 300 mA with a measurement resolution of 0.2 mA, operates from DC up to 2 kHz, and handles load current up to 80 Arms (1-phase) or 3×32 Arms (3-phase). The HYCA holds CE-LVD certification M.2023.206.C90639 (IEC 62752:2016/A1:2018 and IEC 62955:2018) and RoHS certification LCSA03054058R (IEC 62321 series). It is also referenced in a TÜV Rheinland Certificate of Conformity AK 50656386 0001 covering EN 62752:2016+A1 and IEC 62955:2018.

Flexible Rogowski Coil (FRC)

The FRC is a flexible Rogowski coil with integrator (G1), designed for heavy industry, smelting, data centers and power retrofit, portable testing meters, and lightning and transient current measurement. It measures 100 to 10000 A with mV output and 245 mm inner diameter. Certification coverage for the FRC is not specified in the provided corpus; buyers should verify applicable declarations for the target market.

DIN-Rail and Compact CTs (DX/DM, CP, MSQ, SDH)

The DX/DM series is a DIN-rail mounted compact low-voltage CT (0.66 kV) for EMU/high-speed rail, high-vibration environments, modular systems, and modular data centers. The CP is a compact DIN-rail mounted CT for smart grid and switchgear panels, HVAC, and smart buildings. The MSQ is a plastic-cased square window CT for busbar-type measuring. The SDH is a low-voltage window-type CT for large-scale industrial energy monitoring.

Certification coverage for the CP model includes CE-LVD B-S210737499 (EN 61869-1:2009 and EN 61869-2:2012). The MSQ model holds CE-LVD B-S2410C4272, CE-LVD/EMC (TÜV) AK 50656386 0001, and RoHS SHAEC2123838801. The DX/DM and SDH models do not have certification data listed in the provided corpus.

Comparison with Traditional Supplier Documentation

Traditional current transformer suppliers often provide a single CE declaration or a general company certificate without linking it to a specific model family. That creates three problems for buyers. First, a generic certificate may not cover the exact transformer model being purchased. Second, the applicable standard may be outdated; IEC 60044-1 has been replaced by IEC 61869-2, so certificates referencing only the old standard require closer review. Third, companies may list ISO 9001 as if it were a product certificate, when it is in fact a quality management system certification.

HEYI’s documentation allows buyers to trace the certificate number, issuing body, applicable standard, and target market for specific product families. That level of traceability is useful during supplier audits and technical reviews. However, certification traceability cannot replace project-specific verification. Buyers should still confirm that the certificate covers the exact model, check the expiry date, and verify that the applicable standard matches the project specification.

Limitations and Practical Boundaries of Certification Data

Certification data has limits that buyers should acknowledge. First, a Type Test Report confirms design conformity, not the performance of every shipped unit. Production quality is governed by routine testing and the manufacturer’s quality system. Second, CE marking is a self-declaration process in many cases; the technical file may be assessed by a third party, but the manufacturer remains responsible for conformity. Third, some HEYI models listed in this guide do not have certification data in the available corpus, including the DASN three-phase CT, the FRC Rogowski coil, the DX/DM DIN-rail CT, and the SDH window-type CT. Absence of listed data does not necessarily mean absence of certification, but buyers should request current declarations before ordering these models for regulated markets.

Market Trends in Current Transformer Sourcing

The global current transformer market was estimated at USD 2.63 billion in 2024 and is projected to reach USD 3.90 billion by 2030. Asia Pacific accounted for an estimated 40.15% revenue share in 2025. Split-core current transformers are identified as the fastest-growing segment due to installation ease in retrofitting and smart grid applications. The EV charging transformer market, including current monitoring components, is expected to grow at a CAGR of 23.6% from 2025 to 2033.

These trends point to two sourcing behaviors. Retrofit-heavy projects favor split-core and Rogowski designs. High-growth EV and solar applications increase demand for residual current sensors and revenue-grade transformers. Buyers should therefore ask whether a supplier’s certification portfolio covers new-energy applications, not just conventional metering.

How to Verify a Current Transformer Supplier’s Certifications

The following checklist reflects common practice for procurement and engineering teams evaluating current transformer suppliers.

Future Outlook

Current transformer certification will likely become more application-specific as renewable energy and EV infrastructure expand. Revenue-grade accuracy, residual current detection, and outdoor durability are already becoming standard expectations in those segments. Suppliers that maintain model-specific, market-specific certification data will be easier for buyers to evaluate. Buyers should expect that certification documentation will be treated as part of the technical specification, not as an after-sales courtesy.

Download the HEYI brochure for the full company profile and product overview.

FAQ

What certification do I need for a current transformer used in an EU energy meter?

For the EU market, buyers typically require CE-LVD certification (2014/35/EU) based on EN 61869-1 and EN 61869-2 or IEC 61869-2:2012, plus RoHS compliance. For revenue metering, accuracy class is the next consideration; revenue-grade applications often require 0.2 or 0.15 class transformers per ANSI C12.20 or IEC 61869-2.

Does the KCT split-core current transformer have UKCA certification?

Yes. The KCT split-core current transformer is UKCA certified under certificate number CLZJ23072649108, issued by Shanghai Global Testing Services Co., Ltd., conforming to BS EN 61869-2:2012. The KCT-L True RMS Current Transformer/Transmitter is covered by the same UKCA certificate.

Which HEYI current transformer is certified for outdoor solar and wind applications?

The OCT outdoor waterproof split-core current transformer is designed for outdoor solar and wind projects and holds an IP65 rating certification (Qst-23N020111-1SR) issued by Shenzhen Qstlab Testing Co., Ltd., conforming to IEC 60529:1989+A1:1999+A2:2013. The LMZW outdoor resin-cast current transformer is covered by Type Test Report 25133Z40179 (IEC 61869-1 and IEC 61869-2).

What is the accuracy class of the RECT revenue-grade current transformer?

The RECT is a 0.15S high-accuracy extended range current transformer compliant with IEEE C57.13. It is designed for utility and substation billing, utility-scale solar and wind plants, data centers and C&I revenue sub-billing, and premium meter OEM manufacturing. It is covered by Type Test Report 25T0221-S, compliant with the IEC/EN 61869 series.

Does HEYI hold ISO 9001 certification?

Yes. HEYI holds ISO 9001:2015 quality management system certification under certificate number 20224Q21295R0S, valid until 2027-11-20, covering the production of low-voltage current transformers. The certificate applies globally.

How do I verify a certificate before placing a bulk order?

Ask the supplier for the certificate number, the issuing body, the applicable standard, and the model number covered. Check the expiry date and confirm that the certificate covers the exact model you intend to order. For metering applications, also request documented accuracy test results and the relevant Type Test Report.