Why is it required that the capacitors for the circuits connected in 110 V have a minimum working voltage of 100 V and in the network of 220 V are for 400 V?
What happens is that the value 110 V, of the grid of 110 V or 127 V as would be correct is the value RMS, that is, a value that does not correspond to the maximum that the voltage reaches in a cycle. This value corresponds to what we should have of energy if the voltage were continuous. Thus, in reality the voltage of 110 V in each cycle oscillates between 0 and 110 x 1.41 V = 155 V. This, therefore, is the voltage peak. A capacitor in a 110 V circuit must support this peak with a certain tolerance, so we have specified that it has at least 200 V of working voltage. In the case of the 220 V grid, the voltage reaches 330 V, hence we recommend capacitors with at least 350 V or 400 V.
