Current Transformer Certifications: CE, Accuracy, and Specs

A current transformer (CT) is an instrument transformer that steps down alternating current to a level that meters, relays, and monitoring systems can read safely. For buyers in Europe and other regulated markets, checking CE documents is not a procurement formality; it is a core part of supplier evaluation. This article explains what CE conformity means for current transformers, which certificates and accuracy classes matter, and how to apply this checklist to real products from HEYI Electrical.

Why CE Status Is a Decision Factor for Current Transformer Buyers

CE marking applies to products placed on the European Union market. For low-voltage current transformers, the relevant directives often include CE-LVD (2014/35/EU) and CE-EMC (2014/30/EU). The underlying product standard for inductive measuring transformers is usually IEC 61869-2 or EN 61869-2, which is why buyers should look for these standards on certificate documents.

Searching for “current transformer manufacturers with CE” is a reasonable starting point, but the more useful question is whether the certificate covers the exact model being purchased. A generic company CE declaration is weaker evidence than a certificate that names the product family and cites a measuring transformer standard.

CE-LVD and CE-EMC

CE-LVD relates to electrical safety requirements under the Low Voltage Directive. CE-EMC relates to electromagnetic compatibility. For current transformers, certificates should cite standards such as EN 61869-1, EN 61869-2, or IEC 61869-2. Some HEYI products also hold UKCA certification for the United Kingdom, and different product families can carry separate compliance documents.

RoHS and Type Test Reports

RoHS compliance limits hazardous substances and is commonly verified through IEC 62321 series test reports. For higher-risk or metering-grade products, type test reports provide additional evidence that a product was tested against a recognised standard. These documents complement, but do not replace, the CE certificate.

Market Context: Current Transformer Demand and the Split-Core Trend

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 the largest regional revenue share at 40.15% in 2025. Split core current transformers are identified as the fastest-growing segment, mainly because split-core construction can be installed around an existing cable or busbar without disconnecting the circuit. This is valuable for retrofits, smart grid projects, and energy monitoring upgrades.

Certified Current Transformer Portfolio: HEYI Electrical Product Map

WENZHOU HEYI ELECTRICAL CO.,LTD (HEYI) is a current transformer and current sensor manufacturer based in Wenzhou, Zhejiang, China. HEYI was established in 2012, operates a 10,000 m² factory, and exports to markets including Southeast Asia, South Korea, Europe, South America, Australia, Africa, the Middle East, and North America. The company supports OEM, ODM, customised production, and bulk manufacturing.

HEYI’s current transformer range covers split-core, solid-core, busbar, mini, three-phase, Rogowski coil, outdoor, revenue-grade, and residual-current sensing products. The models below are commonly requested in CE-regulated projects.

MSQ Series: Solid-Core and Busbar-Type Current Transformers

The MSQ current transformer is a plastic-cased solid-core CT with a square window. It suits busbar mounting in switchgear panels, HVAC, smart buildings, and data centers. It covers 0–6000 A with secondary output options of 5 A, 1 A, mA, or mV, and accuracy classes up to 0.2/0.2S. Custom options include housing material, housing color, accuracy, output, capacity, and OEM.

For EU buyers, the MSQ series has CE-LVD evidence issued by TÜV SÜD Product Service GmbH under certificate N8A 114572 0001 Rev. 00, and another CE-LVD certificate B-S2410C4272 from Beide. It also falls within ISO 9001:2015 quality management certification 20224Q21295R0S and has SGS RoHS verification for the EU market.

KCT Series: Split-Core Current Transformers

The KCT is a split-core clamp-on CT with an inner diameter of 0–50 mm. It uses PA plastic, silicon steel sheets, ferrites, and pure copper enameled wire. Measurement range is 0–1000 A, with output options of 5 A, 1 A, mA, mV, RS485, or 4–20 mA, and accuracy classes 3.0, 1.0, or 0.5. Because the core opens, it is suitable for retrofit installations, solar and wind monitoring, smart grid panels, and EV charging infrastructure.

KCT carries CE-LVD under certificate ET16118324-LVD, a RoHS test report under LCSE03115005R, and UKCA certification under CLZJ23072649108 for the UK market.

DP/HK Series: Busbar Split-Core Current Transformers

The DP and HK models are busbar split-core CTs designed for larger conductors, with a window size up to 80 x 160 mm and current range up to 8000 A. They are used in smart grid switchgear, EMS and energy management, smart buildings, data centers, and solar, wind, and storage systems. Available outputs are 5 A, 1 A, mA, or mV; accuracy classes are 3.0, 1.0, or 0.5.

The DP/HK series has CE-LVD certification N8A 114572 0002 Rev. 00 from TÜV SÜD, CE-EMC certification B-E2505D2378 from Beide, and RoHS certification SHAEC2123838801.

RECT Series: Revenue-Grade Current Transformers

The RECT is classified as an extended range current transformer and a revenue-grade billing CT. It offers 0.15S accuracy and is IEEE C57.13 compliant, using an epoxy resin-insulated structure with a 0–78 mm inner diameter. It covers 0–1000 A with secondary output of 5 A or 1 A, IP65 protection, UV resistance, and OEM customization.

For global projects, RECT is covered by a Type Test Report numbered 25T0221-S, issued by Suzhou Electrical Apparatus Science Research Institute Co., Ltd., conforming to the IEC/EN 61869 series.

Other Certified CT and Sensor Families

• KCD: smart split-core CT with RS485 and Modbus RTU output. Range 0–1000 A, accuracy 1.0, output 4–20 mA, inner diameter 0–50 mm. Used in smart buildings, elevator monitoring, O&M services, and Beijing/Hangzhou metro lines. It is RoHS compliant for the EU.
• HYCA: residual current sensor for EV charging and solar or storage applications. It detects differential current up to 300 mA with 0.2 mA resolution and has CE-LVD certification M.2023.206.C90639 and RoHS certification LCSA03054058R.
• LMZW: outdoor resin-cast CT with IP65 rating, UV protection, and Type Test Report 25133Z40179 conforming to IEC 61869-1 and IEC 61869-2.
• OCT: outdoor waterproof split-core CT with IP65 certification Qst-23N020111-1SR.
• DASN: three-phase integrated CT for DIN-rail mounting, 0–1000 A, output 5A, accuracy 1.0.
• FRC: flexible Rogowski coil for large conductors, 100–10000 A, output mV, inner diameter 245 mm.

Comparison Table: HEYI Current Transformer Series at a Glance

This table is based on HEYI’s published product specifications. Certificates should always be checked against the purchased model and delivery date.

Step-by-Step: Evaluating a Current Transformer Manufacturer with CE

1. Define the application and environment. Determine whether the CT will be used for billing, load monitoring, protection, EV charging, solar, storage, or building sub-metering. This defines the accuracy and output requirement.
2. Check certificate scope and standards. Ask for the certificate PDF and confirm that the exact model is listed and that the standard is IEC 61869-2, EN 61869-2, EN 61869-1, or a related applicable standard.
3. Match accuracy class to the measurement purpose. Revenue-grade billing typically needs 0.2 or 0.15 accuracy under ANSI C12.20 or IEC 61869-2. For general monitoring, 0.5 or 1.0 is often sufficient.
4. Confirm output and secondary burden compatibility. Conventional meters often use 5 A or 1 A secondary output; power monitors may use mA or mV; IoT and PLC systems may need 4–20 mA or RS485 output.
5. Check physical mounting. For an existing panel without interruption, a split-core CT is practical. For new busbar assemblies, solid-core or busbar CTs can be more compact. DIN-rail CTs are useful for organized panel builds.
6. Request samples and document scans. A sample order is the final verification step. The manufacturer should provide certificate copies, wiring guidance, and test support.

Use Cases: Where Each Certified Current Transformer Fits

• EV charging piles: HYCA type B residual current sensors detect 6 mA DC and 30 mA AC leakage in line with IEC 62752. KCT split-core CTs can be used for charger load monitoring.
• Solar and wind plants: DP/HK busbar split-core CTs suit inverter and plant monitoring; RECT revenue CTs suit generation metering; LMZW and OCT suit outdoor and weatherproof installation points.
• Utility and substation billing: RECT with 0.15S accuracy and IEEE C57.13 compliance provides evidence for revenue-grade measurement. MSQ with 0.2/0.2S is suitable for panel metering and distribution monitoring.
• Buildings and data centers: CP, MSQ, and DASN can fit switchgear, MCC, RPP, and branch monitoring panels. KCD adds RS485 communication for building management integration.
• Smart grid retrofit: KCT and DP/HK split-core designs can be clamped around energized conductors, reducing downtime and making retrofits more practical.

FAQ

Conclusion

Selecting a current transformer for a regulated export project means combining three things: a clear application requirement, a matching accuracy and output specification, and traceable conformity documents. HEYI Electrical provides a broad portfolio with CE-LVD, CE-EMC, RoHS, UKCA, and type-test evidence across MSQ, KCT, DP/HK, RECT, LMZW, OCT, HYCA, and KCD product families.

The next step is to map your circuit parameters to a specific model and request certificate scans and a sample for verification. For current product documentation, visit www.heyiele.com or download the brochure below.