Where functionally connecting ME equipment to other items of the system or other systems could cause leakage current limits to be exceeded, safety measures incorporating a separation device are applied, having the dielectric strength, creepage and clearance of one means of operator protection for the highest voltage across it in a fault condition, the working voltage being that highest fault voltage but never less than the maximum mains voltage (earth potential differences between class I items without a common earth, and connections to nurse-call or data systems, are typical cases); checked by the tests of 8.8 and 8.9.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.