Dual power supplies on the same circuit

No, not really. This is a perfectly good way to protect against a power supply failing, as long as it doesn't fail in such a way as to draw massive amounts of current (very unusual).

Normally people will put them on different circuits to also protect against blown breakers, and use different power sources for those circuits sometimes to protect against outages and blown UPSes. If you are only worried about a failing PSU you don't need to worry about that.