Jon Rennie

The term “instrument transformer” is a general classification.  It applies to electrical devices which change current and voltage from...

Potential (or voltage) transformers consist of two separate windings on a common magnetic steel core. One winding consists of fewer turns of heavier copper wire on the core. 

Instrument transformers are used in both indoor and outdoor applications.  The function of the instrument transformer is essentially the same but there is a significant difference in the construction of indoor vs. outdoor units.