1.6 Types of Leakage Current Measurement
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Class-I equipment does not require the measurement of enclosure leakage current since metal enclo-
sures must be grounded for electrical protection.
However, when the protective earth conductor becomes
disconnected (single fault), the enclosure is no longer grounded for protection and must be measured.
For Class-II equipment, all enclosures are ungrounded for electrical protection and must be tested.
Ungrounded equipment are often made of plastics and other insulated materials. Since leakage current
flows through the human body, the standard stipulates that a probe is applied to metal foil the size of a
hand pressed against the insulated material. Use the 9195 enclosure probe supplied with the instrument
for measurements involving this instrument.
There are two paths for touch current to flow: "enclosure
human body earth" and "enclosure
human body enclosure." Note that for "enclosure human body enclosure" to occur a person
must touch two electrically isolated (separate) enclosure sections not two sections on the same enclo-
sure.
Touch current measurement
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