Power ratings for all components of simple ekettle?

For a simple eKettle which would include element, wire, plug, and outlet what is the max rating for each component. I know the amps should not exceed 80% of the wire, but what about everything else?

Here is why I ask. I am making a simple "Stove assisted" eKettle where the element will be running on full power the whole time. The element I already have is 1650W (120V) which will pull 13.8A. My kitchen GCFI outlet is for 15A plugs, but the breaker for this outlet is 20A. If I was to use this outlet I would have to use a 15A rated plug and a 15A outlet (on a 20A breaker) which would be 92% of its max. Is this okay for the plug and outlet or should I just find a 1500W element? As a note, I am in an apartment and cannot rewire in a 20A outlet.

it'll work, but it'll stress both the element and the plug/socket, which will shorten the life of both. My recommendation would be to (since you already have the element) temporarily wire it up, drop it in some water, and plug it in. Carefully monitor the heat on the plug (test by touching the plug itself and by touching the screw holding the outlet plate on and see if either is starting to warm up). If there is no issue with heat buildup during a time equal to a full brew session + 30%, then you should be fine. If there is any heat, you probably want to drop to the 1500W element. (The 30% is standard engineering safety factor. For example, if you normally heat over 40min and boil for 60min, then your test should last 130min.)