some of the materials used are, well, less than impressive. i have my doubts as to weather they would be accepted elsewhere.
I do stand corrected, however, on 550-8-f-1 .
550 has some strange things going on....
some codes here, could not be used in other than mobile homes, as the heat tape off the bath GFI is commonly done in 550-8-g. Some of these units are sold skirting that is barely windproof, and if the h2o line comes in from the wrong end of the deal,,,,,well you know,,,,do the math!
one other impressive point are the "self-contained" devices. these simply have a stab-lock teeth type mechanism that makes to a wire introduced, as it is snapped shut. i do not know of the rating/listing of such devices, but i have seen more than 2 wires
( 3 pieces of 14-2 nm) in one device, which means the contacts on one side are actually making to two wires each. on service calls, these are seen as load related problems, and i often wonder who or what inspects these units, if at all, before they hit the road.