15A outlets on 20A circuits and tandems

[John Coloccia]

1) electric heaters cause fires because they get tipped over, are stuck near drapes/bedding, or are used on wholly inadequate extension cord.

2) The insurance company will say that the house was wired exactly to the NEC. This is how practically every modern home in the USA is wired. Go into your basement and look at all the 20amp breakers. Now look around at how many outlets you have with a horizontal spade plug available.

3) As far as I know, most 15A and 20A outlets are identical, and come off the same line. The only difference is the faceplate, and the only reason the difference exists is to keep someone from plugging a 20A piece of equipment into a 15A circuit. This is required by code and therefore manufacturers happily make different face plates.

And there is no way you're going to melt any metal anywhere unless you're talking about a fuse, and that's REALLY thin metal. Generally, thinner metal heats up and sets the stuff around it on fire, notably plastic insulation and wood.

Finally, as far as I know, UL requires a 15A receptacle to be designed to live on a 20A circuit.