If the pin/sleeve was setup on the exterior then an appropriate length of cord would not raise my eyebrow.
'Cord' (400.7/400.8) useage is one item that raises questions, whenever it appears on a plan/sketch, or is buried within the 'Electrical Notes' of a design professionals plans/specs.
BTW, with 5k gal of propane, & the solar storage, that sounds like someone preparing to be a survivor!
