How do I choose between a current transformer and a Hall effect current sensor?

Choose a current transformer for standard alternating current systems and non-invasive energy submetering. Pick a Hall effect current sensor when measuring direct current or complex, distorted waveforms. Hall effect units deliver proportional DC output voltages like 2.5V, while CT units produce AC millivolt, milliamp, or transmitter signals.

Can I connect an ac current sensor directly to a PLC analog input?

Direct connection depends on sensor output type. A current sensor module producing 4-20mA connects directly to standard PLC analog input channels. If your sensor outputs AC signals like 50mA, 333mV, or 1V, you must verify your analog card accepts raw AC CT inputs or add a signal conditioner.

What primary current ratings are standard for split core current transformer models?

Compel carries split-core transformers across primary ratings including 5A, 10A, 20A, 30A, 50A, 100A, 150A, and up to 2000A. Select a unit rated just above peak continuous circuit draw to preserve reading accuracy without saturating the magnetic core.

Why should a current transformer clamp never operate with an open secondary circuit?

Operating an unburdened milliamp-output current transformer clamp can generate high secondary voltages across open terminals. Models with built-in burden resistors outputting 333mV or 1V protect technician safety by clamping peak open-circuit voltage to safe millivolt levels.

When should I install a current sensor switch instead of a continuous transmitter?

Use a current sensor switch, such as model M3050 covering 0.2A-50A, for basic run-status confirmation, proof of flow, or motor trip alarms. Continuous transmitters like model QNDBK2-24 convert 0-100A to 4-20mA signals for detailed energy profiling, trend tracking, and load logging.

Current Sensors

10 products available

Compel supplies industrial current sensors for submetering, motor protection, and facility energy management across production plants. These instruments measure electrical current in single-phase and polyphase circuits without interrupting supply lines. Our stock spans split core current transformer hardware, clamp-on instruments, automated alarm switches, and wideband oxygen sensor kits for engine diagnostics. Every design delivers accurate feedback to programmable logic controllers, indicators, or telemetry hardware.

Industrial plants, electrical contractors, and machinery builders rely on Compel for dependable inventory and fast dispatch. We stock standard clamp styles and surface modules with verified ratio curves and millivolt, milliamp, or relay outputs. You get immediate access to technical parameters, reliable replacement availability, and direct shipment to your site.

10 products in Current Sensors

Split-core Hall effect current sensor for 10A to 100A applications.

Current Sensors

Split-Core Current Sensor | Clamp-On Hall Effect | 10A to 100A Range

TBS-06482SENS-00316

£28.99

QNDBK2-24 AC 1A-100A 4-20mA split core current sensor transmitter clamp CT transducer.

Current Sensors

Current Sensor Transmitter | 0-100A to 4-20mA | Split Core Clamp

TBS-06426SENS-00280

£37.99

M3050-M3086 current sensor module for detection and alarm, transformer control, and current sensing.

Current Sensors

Current Sensor | Transformer Control Switch | Alarm Detection Module

TBS-06413SENS-00270

£13.99

Current Sensors

Current Sensor Switch | M3050 Induction Relay | Alarm Output

TBS-06423SENS-00278

£12.99

QNCTK1-16 100A 333mV and QNCTK1-10 50A 333mV split core current sensor transformer clamp CT.

Current Sensors

Core Current Sensor | 100A 333mV Output | Clamp-On CT Design

TBS-06421SENS-00276

£11.99

Clamp CT Current Transformer 100A, a precise current sensor for electrical measurements.

Current Sensors

Split-Core Current Sensor | Non-Invasive Clamp Transformer | 100A 50mA Output

TBS-06409SENS-00268

£10.99

SCT013 5A-60A non-invasive AC current sensor, a reliable split core current transformer for various applications.

Current Sensors

Non-Invasive AC Current Sensor | 30A Split-Core | For Energy Monitoring

TBS-06419SENS-00275

£5.99

SCT-013-000 30A 50A 100A open-close current transformer, a non-invasive AC current sensor with split core design.

Current Sensors

Split-Core Current Sensor | Non-Invasive AC Clamp | 100A SCT-013-000

TBS-06393SENS-00253

£12.99

SCT-013-000 non-invasive split core current transformer, a versatile AC current sensor for various amperage ratings.

Current Sensors

Current Sensor | SCT-013-000 Split-Core Transformer | 100A 1V Output

TBS-06407SENS-00267

£15.99

Car O2 Air Fuel Ratio Wide-band Gauge Kit, featuring a display and a strain gauge for precise measurements.

Current Sensors

Car O2 Air Fuel Ratio Gauge | Wideband Current Sensor Kit

TBS-06378SENS-00242

£114.99

Selecting Core Topology: Split-Core vs Inline Mounting

Choosing between core styles depends on physical access to conductors during installation. A split core current transformer snaps directly over primary cabling, eliminating downtime on live industrial networks. Technicians commonly install clamp current sensor units during plant energy audits or panel additions where service shutdowns interrupt production.

Solid-core modules and surface-mount sensor modules mount permanently during panel builds or internal circuit board assemblies. When working inside tight enclosures, verify window dimensions against cable bundles to ensure clean closure without pinching wire insulation.

Split-core clamp units: Enable non-invasive retrofits without breaking line conductors.
Board-mount modules: Integrate directly into control circuitry using SMD or TQFP footprints.

Matching Signal Output to Control Hardware

Matching sensor output to your automation interface prevents signal scaling errors. Current transformers typically output an AC current signal, such as 50mA, which requires a burden resistor or direct CT input card. Other designs deliver low-voltage outputs, including 333mV or 1V, designed for direct connection to digital energy meters and microcontrollers.

For plant PLC integration, transmitter models convert signals into a standard 4-20mA loop. When monitoring DC circuits or variable-frequency drive lines, choose a Hall effect current sensor with analog voltage output such as 2.5V or 2.5±2V.

Millivolt signals: Common outputs like 333mV and 1V connect safely to data loggers and metering panels.
Loop powered 4-20mA: Transmits signals over long-distance industrial instrumentation runs without line loss.
Relay switches: Models like M3050 provide switched contact output once current exceeds trip thresholds.

Primary Current Sizing and Operating Range

Size your ac current sensor so normal operating loads fall within the accurate range of the core. Running sensors near their lower floor reduces measurement resolution, while exceeding rated amps causes saturation and signal distortion. Common input ratings include 5A, 10A, 20A, 30A, 50A, and 100A for panel loads, extending up to 2000A for heavy distribution feeds.

For alarm switching duties, adjust the trip threshold according to expected motor running amps. Adjustable switch modules cover detection bands such as 0.2A-50A to trigger indicator beacons, relays, or interlocks when equipment stalls or idles.

Rated primary amperage: Select ratings matching maximum feeder capacity, from 1A up to 100A or higher.
Trip threshold calibration: Confirm adjustable ranges like 0.2A-50A match baseline motor idle current.

Buying guide

Choosing Current Sensors

How do I choose between a current transformer and a Hall effect current sensor?: Choose a current transformer for standard alternating current systems and non-invasive energy submetering. Pick a Hall effect current sensor when measuring direct current or complex, distorted waveforms. Hall effect units deliver proportional DC output voltages like 2.5V, while CT units produce AC millivolt, milliamp, or transmitter signals.
Can I connect an ac current sensor directly to a PLC analog input?: Direct connection depends on sensor output type. A current sensor module producing 4-20mA connects directly to standard PLC analog input channels. If your sensor outputs AC signals like 50mA, 333mV, or 1V, you must verify your analog card accepts raw AC CT inputs or add a signal conditioner.
What primary current ratings are standard for split core current transformer models?: Compel carries split-core transformers across primary ratings including 5A, 10A, 20A, 30A, 50A, 100A, 150A, and up to 2000A. Select a unit rated just above peak continuous circuit draw to preserve reading accuracy without saturating the magnetic core.
Why should a current transformer clamp never operate with an open secondary circuit?: Operating an unburdened milliamp-output current transformer clamp can generate high secondary voltages across open terminals. Models with built-in burden resistors outputting 333mV or 1V protect technician safety by clamping peak open-circuit voltage to safe millivolt levels.
When should I install a current sensor switch instead of a continuous transmitter?: Use a current sensor switch, such as model M3050 covering 0.2A-50A, for basic run-status confirmation, proof of flow, or motor trip alarms. Continuous transmitters like model QNDBK2-24 convert 0-100A to 4-20mA signals for detailed energy profiling, trend tracking, and load logging.