[RE-wrenches] Offgrid labeling questions

[Jay]

Hi All

My question is about labeling the following. 

I’ve got a fully offgrid system enclosed in a dedicated power shed, 250’ away from the house. 
AC is routed to a main panel external on the house. So no need to enter power shed to shut off the house. 

48v battery
150v max pole mounts
120/240v, outback 
Backup generator installed just outside of the power shed. 

I’m confused as to what labeling I need in the power shed. 
And 
Can I get away with a “authorization personal only” on the door instead?  And if so what would be the code reference 

Thx

Jay