When were these types of electric connections disallowed? Water heater manufactured in 2012.
I don’t think that I’ve never seen a flexible cord stand almost straight out of a receptacle. Was that possibly NM or UF cable with a cord cap on it?
The problem isn’t the cord. The problem is the male plug-in connector. As far as I am concerned, they were never allowed.
I don’t think They have ever been allowed either water heaters are not portable
I have seen some small 15 gallon 110 units with a plug from the factory, but a 220 unit around here must be hard wired in conduit.
The NEC would permit most of the wiring methods in chapter 3 including different cable types providing that they were not subject to physical damage. A plug and receptacle is not permitted.
Water heaters are not listed for use with flexible cord as they do jot meet the requirements of Article 400.
If that is NM, cord caps are not listed for use with that cable type.