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  • Overview
  • Performance
  • Applications
  • Get a Quote


The RCT1A is a genuine current transformer (CT) replacement but has all the intrinsic benefits of a thin, light-weight, flexible, clip-around Rogowski (sense) coil. Just like a CT the RCT1A secondary output is an industry standard 0 to 1A (5VA p.f. 1) instantaneous current proportional to the measured primary current.

Typically the RCT1A is used with power, current and power quality meters and is an ideal replacement for CTs in retrofit applications to avoid plant shutdown, applications with limited space for installation and particularly where existing monitoring equipment designed for a 0 to 1A CT input is installed.

Standards and Approvals

  • CE marked
  • Complies with EMC EN 61326-1
  • Complies with IEC61010-1
  • PEM Ltd is an ISO9001:2015 registered company
  • Patent pending application no. PCT/EP2012/053893


Rated current (rms)

500Arms to 50kArms

Rated output (Full scale FS)

1A rms

Output limit

120% FS (1.2A rms)

Supply voltage

24Vdc (+/-20%)

Maximum input power

For 5 ohm burden, 100% Rated current, 13W


For 1.25 ohm burden, 100% Rated current, 3.5W

Operating temperature range

–5℃ to +40℃ (Integrator electronics)


–20℃ to +80℃ (Coil and cable)

Bandwidth (-3dB)

0.6Hz to 5kHz

Phase shift @50Hz

< 0.5 degrees

Accuracy (typ.)

±1.0% of reading


(20% to 120% FS, 25℃)

Output load

5 ohm to 1.25 ohm

Coil Length

300mm, 500mm or 700mm (Custom lengths available)

Cable Length (coil to integrator)

1m or 2.5m (Custom lengths available)


  • Traceable calibration (certificate included)
  • No magnetic materials means excellent linearity < 0.2% reading
  • Fully isolated measurement
    • Isolated power supply 2kVdc
    • Coil rated at 2kVpeak (withstand test is 4kVrms / 50Hz / 60 sec)
  • Small DIN rail (or panel mount) enclosure – UL94 V-0 rated


Isolated BNC-BNC cable split option between coil and electronics to enable ease of installation e.g. threading through existing conduit. Standard cable permanently fixed.


Retrospective current monitoring with existing 1A/5A metering systems

Flexible clip-around, RCT1A sense coil and a bulky fixed core metering current transformer both 4000A rated primaryUntil recently, flexible coil current sensors (Rogowski coils) have provided voltage or mA outputs proportional to the measured current; perfect for data acquisition systems but not compatible with traditionally installed 1A/5A metering systems. This compatibility issue is eliminated with the new RCT1A current sensor from PEM Ltd. The RCT1A is a flexible, clip-around, light-weight current sensor with a 0-1A output. It allows safe and simple installation and is compatible with energy meters that are typically fed from current transformers (CTs).

Installation of "retrospective" power and energy monitoring systems can be costly if the installation requires plant shutdown.  Installation conditions are often less than perfect, and lack of space can mean bus-bars must be repositioned to accommodate large iron core CTs making shutdown unavoidable. This poses a particular problem when the nature of the business cannot accommodate electrical shutdown e.g. hospitals.

Other applications include:

  • Power ultilities
  • Arc furnaces
  • Building services
  • Custom versions
    • Rogowski coils immersed in transformer oil
    • Long coils and cable runs

Quote Request RCT1A

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