The CPC1390G is a 4-pin, single pole and normally open solid state relay that has input to output isolation of 5000 Vrms. It has a blocking voltage of 400 Vp and does not generate EMI or RFI ...
The Double Pole Single Throw DPST relay is the equivalent of 2 SPST switches (NO Normally Open and NC Normaly Closed) and can be used to switch 2 different loads. As you can see in the schematics ...