[Skywave]

I expect that the phrase 'current transformer' means a transformer of a recent design - i.e. one that is of 'current' manufacture, as opposed to something old and of possibly dubious quality. In the context of its proposed use, safety is obviously paramount - so a new / recently manufactured transformer has been stipulated.
Just an unfortunate mis-application of the word 'current' in the context of something electrical.
The transformer will almost certainly be an isolating transformer.

Al.