Why There Is So Much Variance In The Appearance Of Rogowski Coils

Posted on: 13 November 2017

A Rogowski coil is named after its inventor, Walter Rogowski. A standard Rogowski coil is a helical wire wrapped around a non-iron core of more wire. Both ends of the coil come together and connect. A third wire extends from the connected ends to a digital readout component so that electricians and scientists can get a sense of the amount of current flowing through a conductor or an object that can conduct electricity. However, if you went searching for Rogowski coil suppliers, you would find that these coils have widely wild and different appearances. Here is why. 

Six Different Rubber Colors

If you find a supplier or two, you will see that Rogowski coils are encased in six different rubber casing colors. 

These colors are:

  • Red
  • Black
  • Orange
  • Light Blue 
  • Royal Blue
  • Yellow

This often leads to many confusing questions by purchasing agents. Are these coils all the same, or is there a reason for these coils to be wrapped in six different colors? Actually, yes, there is a reason for the multiple colors. Each color designates a coil with a few different features. One color is the basic coil; it just does what a basic Rogowski coil is supposed to do. The next colors measure higher voltages or a wider range of voltages. Some are also much more sensitive and are able to measure the tiniest differences in electric waves and power surges.

Some are sold with split cores, which have an entirely different purpose altogether. However, the one thing that stands out is that all of the Rogowski coils with rubber cases have two things in common; they measure alternating current and they have rubber casings so that they are extremely flexible and can fit in the tightest of places.

Hard-Case Rogowski Coils

Hard-case Rogowski coils are coils encased in box-like casings and are unlike a coil. These are meant to be installed inside machinery as part of the machinery's daily operations. The hard cases prevent the machinery from rubbing against the coils inside and possibly severing them or causing an electrical fire or electrical accident.

Water-Proof Rogowski Coils

These look like giant rolled firecrackers with tons of neon-colored fuses exiting the center core. It would be impossible to tell that they are Rogowski coils if you were not an electrician or the ads did not tell you what they were. These are only used to measure electrical current in transformers that are submerged in water or some other liquid.