By checking the connectivity of the two pairs of wires (as both are electrically disconnected), the two sets (primary and secondary) can be separated from each other.
But the challenge is first to find which winding is high voltage and which one is low voltage and further more the turns ratio without applying power (that is the challenge) to the transformer
Let me know if there is an answer.
The answer is straightforward. The
primary is, by definition, whichever winding is connected to the supply, and the
secondary is whichever winding is connected to the load!
To identify a winding, apply a continuity test between the accessible terminals using an ohmmeter. To identify the higher-voltage windings, measure the resistance of the coils -the higher-voltage winding will have the higher resistance.