Sounds like a fuse cutout to me. Fuse cutouts are popular in New York City for fire alarm equipment circuits. They contain one or two fuses and a fuse holder for the neutral that gets a solid copper dummy fuse so that the neutral can be disconnected also. Dont'know if this is called a Ryan Box though.
Is there a street box on this install? Back in Mass. we had 'Gamewell" boxes that would send a code to the fire station and sound a real loud horn that the whole town could hear.
A ryan box is a two fuse box, with two 15amp fuse-stats. They are tapped directly off the main (or a transfer switch if their is an emergency system). It is used to power the fire alarm panel.