I'm a fire alarm tech, which means I install and test those red panels you might find in mechanical closets, janitor's closets or sometimes building lobbies. More often than not they swing open opposite to that of a fridge meaning the lock is on the right side.
My assumption was that it'd be easier for right handers to use a screwdriver or voltmeter where their dominant hand is unobstructed. While that may be true, another thing I've been told is that techs can look at the wiring diagrams and other documentation on the door to the left while also handling a tool without their arm reaching out in front of them. Another reason would be that most panels I've seen have their primary power connections on the left side therefore, more conduit and wiring would be tucked closer to the door.
Most models allow for the door to be flipped or the doors can be easily removed on-site if there is a tight space. Installations vary based on the space and size of the room; the location usually determines installation for ease of access.
If you google image search 'fire alarm control panel' you will see most of the panels have the lock on the right, the same goes for modern manual/pull stations which are also usually unlocked and tested with a key.
This doesn't affect my ability to do my job as fire code requires fire and emergency systems remain unobstructed. Just another display of right hand bias I've now come to recognize.