This paper aims to describe the effects of time delays ∆t on the statistical quantification of the common mode current caused by multiple converters operating within the same grid. For this purpose, a circuit simulation and the Polynomial Chaos (PC) method are used to create a surrogate model of the grid. The switching-on time ∆t of each converter is considered as a random variable following a uniform distribution. The resulting model allows to depict a distribution of the common mode current for selected harmonics of the switching frequency. The results provided by the model can be used by the EMC and power engineers to account for the uncertainty caused by the operation of several identical converters.