
1.6 Types of Leakage Current Measurement
14
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
Содержание ST5540
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Страница 29: ...23 2 Chapter 2 Instrument Labels and Screens Instrument Labels and Screens Chapter 2 ...
Страница 80: ...4 8 Changing the Measurement Method Auto Manual 74 ...
Страница 121: ...115 8 9 7 Chapter 7 Instrument System Settings Instrument System Settings Chapter 7 ...
Страница 144: ...7 14 Setting the Backlight 138 ...
Страница 284: ...10 14 Measurement Networks 278 ...
Страница 290: ...11 4 Instrument Disposal 284 ...
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