Testing covers only insulation that forms a means of protection (reinforced insulation included) and insulation between the mains part's opposite polarities ahead of a fuse (tested as one means); component insulation is exempt where the component complies with 4.8, and operator-protection insulation is exempt where it meets IEC 60950-1 insulation coordination. Solid supplementary or reinforced insulation above 71 V peak working voltage has at least 0.4 mm distance through insulation or, where not part of an enclosure and not handled or abraded, is at least two layers each passing the dielectric test or three layers any two of which pass; wound components use interleaved insulation to those rules or wire with solid non-enamel insulation of 0.4 mm, or multi-layer extruded or wrapped insulation passing Annex L with two layers or one extruded for basic, two for supplementary and three for reinforced, sealed and tested at 1.6 times where inter-layer creepage falls below the tables, with mechanical protection where wires cross under tension and routine dielectric tests on the finished component. Solid insulation withstands the Table 6 test voltages (Table 7 for operator protection, with additions for patient protection) for one minute immediately after humidity preconditioning, after any sterilisation and at steady-state operating temperature, de-energised, raised from half over 10 s, held and lowered over 10 s, with waveform and frequency giving at least the stress of normal use (sinusoidal 50 or 60 Hz or d.c. at the peak acceptable), breakdown being uncontrolled rapid current increase whereas corona, or one brief flashover, is not; where individual insulations cannot be tested, foil is applied to insulating surfaces, circuits on each side are shorted so components are not stressed and certified capacitors across the barrier may be disconnected. All insulation, including partition walls, retains its resistance to heat through the service life, checked by inspection and design documentation and, where needed, by ball-pressure tests: enclosure and external insulating parts whose deterioration could be unacceptably risky at 75 degrees (or the ambient plus measured rise) with a 5 mm ball at 20 N for one hour and no impression over 2 mm, and parts supporting uninsulated mains parts at 125 degrees, excluding ceramics, commutator parts, and coil formers that do not serve as reinforced insulation; and every means of protection is designed or protected so that dirt and wear dust cannot reduce creepage and clearance below 8.9, loosely sintered ceramic and beads alone are not supplementary or reinforced insulation, embedded-heater insulation counts as at most one means, and natural latex rubber survives 96 hours in oxygen at 2.1 MPa and 70 degrees without visible cracks.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.