Re: Determining Working Voltage - Drawing a Medical Device Insulation Diagram
The working voltage you mentioned here might be different and it shall be decided case by case basing on the circuit analysis.
I suppose that barrier A is separated by a linear transformer since the working voltage was chose as 288V, so another MOPP on B could be 288V at the worst case in theory.
but in general, I think 250V is enough, especially, A is separated by SMPS. Although the priciple of DI-the working voltage is the whole to which it is subjected, however, B will not subjected 288V when failed in A (SFC) but 250V for AC mains.
The question is when failed in A, what voltage may stress on B considering the actual circuit and possible connection to secondary circuit, also earthed or not earthed of applied part.