The thickness of the accessible parts of reinforced insulation consisting of a single layer shall not be less than those specified in Table 19.Table 19 – Minimum thickness for accessible parts of reinforced insulation consisting of a single layer NOTE The values in Table 19 cover clearances through a possible hole in the insulation and align with IEC 60664-1 Table F.2 for homogenous field conditions. The creepage distance through a possible hole is not considered relevant because it is only stressed when the second electrode (human body) is present.