Which of the following is the MOST redundant power solution?

Two PSUs on individual legs of a single 3-phase circuit still share the same upstream transformer and main distribution panel, so a failure at that common source can affect both supplies.

Both PSUs connected to the same 1-phase circuit share a single breaker and feed, meaning any fault on that circuit simultaneously disables both power supplies.

Two power supplies connected to separate 1-phase circuits each draw from an entirely independent circuit breaker, panel feed, or even upstream transformer. If one circuit trips, loses voltage, or is taken offline for maintenance, the other circuit and its PSU remain fully operational. This architecture eliminates the shared circuit as a single point of failure, providing the highest degree of redundancy among the options.

Using one power supply connected to two circuits provides circuit-level redundancy but the single PSU unit itself is an unmitigated single point of failure.