Robert,
I can understand the ambulance manufacturers asserting that the NEC doesn't apply to them, but connecting the neutral and ground together strikes me as both pointless and dangerous. I can only imagine how thrilled the operator would be the first time he plugged it into an outlet with reversed hot and neutral. Ka-boom.
Mike,
The currently-installed cords are only a few feet long, and they tuck into a storage space so they don't protrude for travel. Nevertheless, I hate them, and they're going to be replaced with a recessed inlet as you described. I rather like the marine-grade ones with the locking ring on the cord cap, which I believe are IP65.
Regards,
John
