Technical Update

Current Injection

Testing current injection is a powerful method for testing cables and busbars or switches and connectors.

Normally, cabling and switchgear are part of a circuit requiring high voltage and high power to operate or test. Injecting the same current at low voltage renders testing safe convenient and controllable. With the right equipment, such testing provides valuable information on the real capacity of components and installations.

In the past, the sheer size of current injection equipment has prevented its practical application, or even transport. But LML’s sister company, Riker Ltd, has won a DTI National Measurement Award (presented by the National Physical Laboratory) for developing hand-portable precision current injectors capable of multi-kA Test Currents.

On railways, this enables on-site testing and calibration of traction supply protection switchgear (see the Riker web page), a very valuable service for railway management and safety: The traction supply tested for its available train-pulling power and the system is thoroughly checked for defects before “going live”.

The same concept applies to testing simpler cables and connectors.

Load currents ranging from benign to severe overload can be accurately injected into components to absolutely determine thermal effects and risks of damage. Connection methods and components can be optimised through objective assessment and comparison.

You can never predict the future but testing can remove a great deal of uncertainty.

For further details please contact Christopher Langridge on 01249 814271 or e-mail your query to sales@lmlproducts.co.uk for my attention.

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