I have attached a picture of a circuit where a hi-pot is applying 4800VAC to a transformer. Also in parallel with that 4800VAC rms are two wires heading into a 600VAC rms multiplexer. I have one relay on each line. The 4800VAC is only applied when the relays are both open. I am not sure of the type of relay that I should get. I am thinking that it should be able to withstand at least 4800VAC rms while open, and then operating voltage should be at least 600VAC (since that is max capability of the multiplexer). Is this thinking correct or can I use a relay with a smaller voltage rating? All help is appreciated.