This is used on Class 1 Appliances. (The ones that use a three core cable). The test is usually carried out for only a few seconds, at a low voltage (less than twelve) using a test current which equates to twice the value of the fuse rating for the appliance.

For this reason this test must NEVER be used on IT Equipment

as it is possible to cause damage. Instead use the Earth screen test following.
Whilst applying this test it is usual to flex the lead to highlight any fractures or poor connections. During the Earth Bonding Test high currents flow, so make sure that the earth clip connected to appliance casing is a particularly secure contact. Otherwise arcing could occur with subsequent damage to the appliance casing.

Earth Screen Test: This test also tests the integrity of the earth connection of the equipment, but as this uses very low voltages and current it is suitable for use with IT and other sensitive equipment. Typical values might be 100mv at up to 100mA.