I am hooking up a system where there is 2 sources of power available. One source is the grid power, and the other is a generator. The grid provides me with 3-phase 380VAC with a neutral wire; and on the other hand, the generator provides me with 3-phase 380VAC BUT no neutral wire. I am using a SPDT relay on each phase, and all relays are controlled through a common signal coming from a micro-controller. So, all three relays are switched at the same time. The load is a battery charger that has a 3-phase input and does not accept a neutral wire, just three hot wires.
Now, my main question is when I am looking for a relay suited for my need, should I look for relays that have a switching voltage rating of 220VAC or 380VAC?
The confusing part for me is that if I measure voltage between one phase and neutral the voltage is 220VAC, but 380VAC line to line. So, I am not sure whether I need a relay with a switching voltage rating of 220VAC or 380VAC!