Clamp-on Current Transformers

Currents from 1mA to 15,000 Amp


A Complete Range for all Applications

Physical and Electrical Specifications to Suit All Applications

Clamp-on CTs are compact hand-held devices offering non-contact current measurement for all types of portable instrumentation, including DMMs, Oscilloscopes and all types of recorders and analysers.

Popular models available ex-stock, all can be made to customer specs

- a very wide range of inputs and outputs are available for all models

- full detailed specs are available on request for any variation


5 Basic Types:


AC Current Transformers

- AC Current Input - AC Current Output - hand held and open-able

Traditional Current Transformers in clamp-on format for portable applications for use with kWh meters or other devices with an AC current input.


Frequency range extends from 45Hz to beyond 5kHz. Medium & large models are available with 1 Amp, 5 Amp & other outputs, and with single or 3 range primaries. M series mini clip-on CTs are not available with 5 Amp output. Open circuit protection available on 1 Amp models.

Medium and Large Models are also available with a combined Current & Voltage Output.


AC Current Transducers

- AC Current Input - AC Voltage Output - the widest range - optimised for modern electronic instruments

With an AC voltage output the clamp-on CT becomes inherently open circuit protected.


A 1 Volt (or even better 100mV) output allows the clamp to operate under optimum conditions.

On Medium and Large models, the .UE is the basic device, single range only and normally with a 1 Volt output.   .U are improved models with outputs up to 5 Volt, and are available as single or 3 range devices.

By standardising on a 1 Volt AC output (or even less) from a Clamp-on CT, the user is assured of the widest range of full scale input currents - from 1 Amp to 3000 Amp.

Identified as xx.U or xx.UE;  also available as xx.UM versions for low current measurement.   xx.3U etc is a 3 range device, switch selectable. Identified as xx.D (1 range) or xx.3D (3 range).


AC Current Transducers

- AC Current Input - DC Voltage Output - special models for data logging & recording.

The AC to DC converter transducer and power via the electronics from the measured current makes this range ideal for use with data loggers, chart recorders, computer data acquisition systems - any equipment which has a DC voltage input and needs to monitor and/or log current trends. xx.DM are designed for lower currents.


AC/DC Hall Effect Clamps

- AC/DC Current Input - AC/DC Voltage Output - for DC & mixed AC + DC measurement  A Hall Effect cell is mounted within the magnetic circuit of the Clamp-on CT, and the necessary conditioning electronics within the handle.   This range of Clamp-on CTs provides an output which is a direct image of the current from DC to 1kHz (or even higher for some models).

1C models are for OEM use and require an external DC power supply, and are supplied to customer specified input & outputs.    .2C and .3C are powered by an integral battery.

The Large battery powered models are all dual range.


Injection Clamps

- Inject a signal into an external conductor

For tracing cables & pipework, identifying individual cables - available with custom windings. All models can be supplied with custom windings for this application.

Download Clamp Information

Northern Design (Electronics) Ltd

T/A ND Metering Solutions

UK 8am - 4:30pm Mon-Fri

Registered Office:

228 Bolton Road, Bradford, UK


Company No: 2237837

VAT No: GB 171311110