FR 50 to 30 amp warning

Its about the amps you can see in your conductors under fault conditions. The circuit the dog bone is connected to has overcurrent protection rated at 50A. The dog bone is required to use 6 AWG conductors which can handle 50A. The cord you connect into he conductors and the conductors between the receptacle on your trailer and the trailer power center are not rated for 50A, only for 30. Hence these conductors can overheat and start a fire in the event of a fault current which exceeds 30A but is less than the 50A that can trip the 50A service breaker. 

No, it is not the same thing as for example a table lamp that uses 16 gauge wire. The conductors between the receptacle on the trailer and the panel are not temporary wiring like a table lamp, they are permanent, and as such the NEC applies. The NEC is intended to keep those conductors from overheating and causing a fire. The breaker in the trailer panel does not protect those conductors as it is downstream from the source feeding the conductors.  

As I said, there are plenty of electrical faults which are sufficiently resistive that they do not trip the breaker. Not only can I imagine them, I've seen them. So, it is your option to use one of the dog bones but know that there is risk involved in doing that. 

if you don't believe me, that's fine, go read the warning label underneath your trailer receptacle. 

The Pod is protected by a main breaker.  The power cord draw is limited to the amperage of that breaker, unless there is dmage to the cord.  A sudden defect causing a short circuit would cause sufficient draw that would trip the 50 amp breaker on the pedestal.  I can't imagine any situation that would cause the cord to create heat and catch fire. 

This is like plugging a device with a number 16 power cord into a twenty amp outlet.  The wire is much to small to carry 20 amps but we do it all the time.

The

The NRTL is putting up an SEP (somebody else's problem) field around the dog bone. They were asked to evaluate and list a product to a standard and they did.  If you've ever read the Hitchhiker's Guide to the Galaxy you'll know what an SEP field is. If you haven't read it, you should   Besides, the manufacturer is their customer, not the consumer.