Flexible Rogowski-Coil CT

A flexible coil current sensor that wraps around the conductor for the fastest installation no cable cutting or power disconnection required. It’s classified into three types based on the integration method.

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Passive Rogowski Coils

1. Indoor Rogowski Coils (UL 2808)

Indoor passive Rogowski coils (no external power required) are standalone coil sensors designed for basic energy metering and power quality (PQ) monitoring. At the sensor (coil) level, the ARCT series specifies an IEC 61869-10 design target of Class 0.5 / Class 0.5S accuracy, and defines its PQ and harmonic measurement design range—covering THD, phase unbalance, and overall network performance, as well as harmonics up to the 51st order at 50 Hz and the 63rd order at 60 Hz.

Reference: Datasheet_ARCT Series_25-1205

2. Outdoor Rogowski Coils (UL 2808)

Outdoor Rogowski coils target the same IEC 61869-10–based accuracy classes (0.5 / 0.5S) electrically, while being engineered for real-world field conditions such as noise, EMI immunity, durability, shielding effectiveness, and installation safety. The ARCT series emphasizes noise resilience through a shielded coil structure and shielded twisted leads.

Reference: Datasheet_ARCT Series_25-1205

3. Revenue-Grade vs. Power-Quality Grade (0.5 / 0.5S) Positioning

Class 0.5 target (energy metering + basic PQ): The ARCT-S series is positioned as a general-purpose Rogowski coil with a Class 0.5–type accuracy target.
Class 0.5S-type target (high accuracy at low current + advanced PQ): The ARCT-CW series is described as a 0.5S-type Rogowski coil optimized for applications where low-current accuracy is critical.

Accuracy & Compliance Notice

Rogowski coil (sensor) accuracy is designed to IEC 61869-10 Class 0.5 or Class 0.5S at the coil level. System accuracy can reach Class 0.5 or Class 0.5S–level performance only through the complete measurement chain coil + integrator + energy meter calibration and is dependent on design, installation, and calibration conditions. Important: IEC 62053-22 (Class 0.5S) certification applies to the finished energy meter as a whole, not the CT front-end (coil/integrator) by itself.

Built-in Integrator Rogowski Coils

Built-in Integrator Rogowski Coils are designed as an all-in-one solution combining the Rogowski coil and an integrated integrator/conditioning circuit to deliver a standard 0.333 V AC (333 mV AC) output that connects directly to meters, submeters, and branch circuit monitoring (BCM) systems.

1. Core message (U.S.-friendly, instantly clear)

Built-in Integrator Rogowski Coils integrate the coil + signal conditioning to provide a 0.333 V AC (RMS) standard output at rated current—ready for direct connection to meters, submeters, and BCM devices.

2. Competitive reference points (what U.S. customers expect to see)

Magnelab RopeCT: Specifies 0.333 V AC output (with 1 V AC option), Accuracy 0.5, Phase < 0.2°, Minimum impedance 1 kΩ, and UL 2808 compliance.
CCS (CTRC): Highlights “conditioning circuit output: 0.333 Vac” and “Flexible, Opening-type AC Current Sensor”, and typically lists accuracy, phase, and power requirement (10–30 Vdc) explicitly.

3. Precision spec language (must be unambiguous)

Fix the output format as RMS:
Output: 0.333 V AC (RMS) @ rated current
Publish Accuracy / Phase in numeric terms and/or with an IEC-based class target:
- Example (Magnelab-style): Accuracy 0.5, Phase < 0.2°
- Example (CCS-style): ±1.0% of reading (5–120%), Phase ±0.50°

Accuracy & Compliance Notice

Rogowski Integrators (0.333 V AC Output)

1. Single-Phase Integrators (0.333 V AC Output)

Single-channel integrators for single-phase or single-circuit measurement. In the ARCT lineup, the integrator family is positioned as “single-phase / three-phase precision integrators,” with ARCT-IT-1 representing the single-phase option.

Reference: Datasheet_ARCT Series_25-1205

2. Three-Phase Integrators (0.333 V AC Output)

Three-channel integrators for simultaneous three-phase (3-channel) current measurement. ARCT-IT-3 clearly specifies 3-channel input/output, making it suitable for 3-phase metering, submeters, and BCM applications requiring three currents at once.

Reference: Datasheet_ARCT Series_25-1205

3. DC-Powered (24 Vdc) vs. AC-Powered (100–305 Vac, includes 277 Vac)

24 Vdc powered: ARCT application examples show configurations where the integrator is powered from 24 Vdc, such as using a 1500 VDC voltage transducer output to supply the integrator.
AC powered (includes 277 Vac): ARCT examples also specify AC power (100–305 Vac) for integrator/meter power. This input range includes 277 Vac, which is common in commercial electrical panels.

Reference: Datasheet_ARCT Series_25-1205

4. Accuracy chain must be explained: Integrator + Coil + Meter

The most important content for buyers is the full measurement accuracy chain because overall accuracy depends on the complete system, not a single component.

Sensor (coil) level target: The ARCT coil design basis specifies IEC 61869-10 Class 0.5 and Class 0.5S targets at the sensor level.
System level target (coil + integrator): ARCT describes a system design approach intended to support IEC 61869-2 / IEC 62053-22 Class 0.5S-level measurement performance when used as part of a complete measurement chain.
Certification note (must be stated clearly): Only the finished meter/system can be formally certified as Class 0.5S—not the coil or integrator alone.

ARCT also states that installation directly affects accuracy, and calls out practical requirements such as: keeping the conductor close to the coil center, maintaining near-90° alignment where applicable, ensuring the clasp is fully closed, preserving the coil’s round shape, and using short, shielded wiring to reduce noise pickup.

Reference: Datasheet_ARCT Series_25-1205

Accuracy & Compliance Notice