550.4 extends the scope of the 'mobile home' section to cover job trailers and other permanent buildings.
When I've powered a job trailer, I've set a pole for the service, and run a flexible cord to the trailer itself. I wasn't allowed to attach the service directly to the trailer. Indeed, I've never seen even a 'manufactured home' with the service attached directly to the structure.
Of course, there are plenty of things I've never seen. I've never seen electricity, but I'm pretty sure it exists
Photomats very often had powerbrough to them through a conduit set either in an extremely shallow groove in the pavement (conduit not buried), or run on the surface of the pavement with a 'speed bump' made over it. Sometimes they were simply added on to the parking lot light circuit
Then again, in those days all they had was a light and a fan.
So far .... we seem to have a draw. Half seem to think the fixed service is OK, and half want the building anchored first.
