(1) GFCIs within receptacle cans are probably desirable over those located at circuit origins—likely partially limiting nuisance trips.
(2) For 50-ampere trailer receptacles, NEC 550 calls out signage:
Turn Disconnecting Switch or Circuit Breaker Off Before Inserting or Removing Plug
effectively mandating breakers at receptacles. Similar requirements are not specified for 30-ampere receptacles or for RV circuits, but maybe someday the requirement will extend to those situations.
(3) Agreed that some trailerhouse wiring is egregious, but there is one qualifying factory AC-hipot test that has to have increased installation quality to some degree. Given past notoriously bad trailerhouse-wiring “expertise/workmanship”—at least some of the riffraff is weeded out with NEC 550/551-specified 900-volt/1-minute//1080-volt/1-second “hot-to-neutral” dielectric-test levels. [I believe this test has been required of California trailer manufacturers for about three decades, and indirectly limited a degree of near-criminal loss of life and porerty.] Though not so much of a problem nowadays, the test would not help eliminating sleazy aluminum branch-circuit terminations.
(4) NEC 551-60 also calls out ground-continuity and receptacle-polarity tests. Trumpy has recently discussed Portable Appliance Testing—apparently common in NZ, AUS (and the UK?) A trailer might be viewed as an “appliance” of sorts. I suppose factory dielectric tests could be considered be roughly comparable to (non-reoccurring) PAT tasks.
[This message has been edited by Bjarney (edited 08-09-2004).]
