Manufacturers of protection devices will normally specify the classification for the protection current
transformer intended to operate the particular protection device concerned.
In addition the classification of protection current transformers indicates accuracy class: 5P – current
transformer will have a ratio error of 1% and phase error not exceeding 60 minutes. 10P – current
transformer will have a ratio error of 3% (no level of phase error specified).
The PR series is a range of two of the most popular classifications of protection current transformers,
5P10 and 10P10. Other classifications are possible (such as 5P20 or 10P20). Please consult factory for
a quotation should you require an alternative classification or a current transformer with dimensions
different to those set out below.