The IEC 60950-1 standard requires that equipment design avoids high temperatures, or shields and separates flammable materials from high temperature parts, uses materials of low flammability both internally and for enclosures, and uses fire enclosures to limit the spread of fire. Compliance can be achieved by using V-2 or better rated, insulation and printed board materials throughout and ensuring adequate spacing between high temperature components and plastic and painted parts. Use of UL listed materials eliminates the necessity for exhaustive and messy flammability testing. Earth leakage is the current leaking from an active circuit to ground. For Class II equipment this shall not exceed 0.25mA, for handheld Class I equipment 0.75mA, and other Class I equipment 3.5mA. The test for Class II equipment requires conductive metal foil to be attached to an area not exceeding 10cm x 20cm on accessible non-conductive parts and the test is made between this and conductive parts. Tests are carried out at the most unfavorable (highest possible) supply voltage.