Clamp Range

Clamp-on Current Transducer with a DC voltage output.


A self-powered transducer is built into the device.   A range of different models is available with a 1Vdc output from 25 Amps.   Higher voltage outputs are available up to 5Vdc but suffer from accuracy degradation at lower currents.

Applications include data loggers and SCADA outstations where current trends are being monitored.

Hall Effect.   Combined AC & DC input sensor with a voltage output.


These sensors combines a magnetic core with a gap into which is inserted a Hall Effect sensor — an electronic device which responds to a magnetic field.   With associated electronic circuitry, the output is an image of the measured current.   These devices can be supplied powered either from an external source or, for portable applications, a battery.   A special model providing just a DC output is available.

Different models are available covering a range from 100Amp to 7,500Amp peak or DC.

Injection Clamps.


Designed to inject an AC voltage signal into a cable to allow the route of the cable to be traced.   Custom designed for each application.

Rogowski (flex) Sensors


An air cored device, commonly wound onto a flexible core.   When wrapped around a cable or cables provides an AC voltage output signal which is an image of the current flowing through the cable or cables.   It is supplied with electronic conditioning circuitry.   These  can be powered from a battery or an external source.

Clamp-on Current Transformer.


Since with a clamp-on CT the input has just one turn, the amplitude of the output current is reduced by the number of secondary turns.   E.g. with a 1000 turns and a current of 1000 Amps, the output would be 1 Amp.   Such basic CTs are therefore ideal for interfacing to legacy instruments which require 5 Amp or 1 Amp inputs, such as traditional kWh Meters.

For a 5 Amp output, medium & large models are available from ~ 250 Amp (depending on application) to 3000 Amp;  with a 1 Amp output, small models are available at 100 & 200 Amp while medium & large as above.


Clamp-on Current Sensor (or transducer) with an AC voltage output.


Here, a resistor is fitted across the output terminals of the transformer to provide an AC voltage signal.   The output depends both on the number of turns & the resistor, which allows the sensor design to be optimised for performance.   Different models cover a range from 1 Amp to 3000 Amp.   Output level of 1V is common but can vary from 100mV to 10V.

These are recommended for new designs.


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