Hi experts. I am making a linear psu capable of O/P 600v @ 300mA. This is for vacuum tube experiments. I need to connect/disconnect the load from the PSU using a switch. I will not turn OFF the PSU itself. I cannot figure out how to switch 600V. My search did not produce any promising results. All I found close is 500V DC circuit breakers that are intended for solar PV application. Those are costly, but I am in doubt how long these will survive at 600V. Please suggest me a solution.