Discuss why the primary of a power transformer would have excessive current

Discuss why the primary of a power transformer would have excessive current


Discuss why the primary of a power transformer would have excessive current if the secondary were short-circuited.  Why would there be no voltage across the secondary if the primary is open?
Explain how a transformer with a 1:1 turns ratio and isolated secondary can be used to reduce the chance of electric shock from a 120-Vac power line.
List or cite any references used