The T-slot innards allows one piece to be used for both the hot and neutral side on the entire family of receptacles (5-15, 5-20, 6-15, 6-20).
Yeah because some of the manufactering do that to keep the tooling cost down.
myself i did see few busted 240 volt verison of it as well and they will make pretty nice firework as well
but the biggest thing that some area just dont bother to change it unless someone tell the mantaince personalle to fix it or change it.
I did see that few time in school building and have to fix it and end up using very hevey duty grade repecale to prevent anymore damage but it will happend sooner or later.
Merci , Marc
