Two identical DC power supplies in parallel for redundancy?
simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. Parallel PSUs with power indicators. V+ will be about 0.7 V below the power supply output voltage due to diode drop. Both PSUs on all the time and, if similar type, will probably share the load 50/50.







simulate this circuit

Figure 2. Relay switched PSU. Both PSUs on all the time but one on standby.







simulate this circuit

Figure 3. DPDT relay switches mains on second power supply (preventing it from wasting power when PSU1 is running). A second contact switches the DC side.

Note my schematics show F1 as a common point of failure. The same is probably true of your home supply. You need to take that into account when designing the system.