GW Instek GLC-9000 User Manual - Manual (Page 16)

GLC-9000 User Manual
16
Single Fault conditions include the following:
1. Earth disconnected (excluding earth leakage
current tests).
2. Disconnected neutral power line.
3. External equipment failure. (Patient leakage
current II, Patient Leakage Current III).
Polarity of the power supply can also be switched
to measure the leakage current under test. Thus
the polarity of the power supply should also be
taken into account.
Measurement
Methods The diagram below shows how the probes, MD’s
and power supply are connected for different
leakage current tests.
Measuring Devices
Background Leakage current (touch current) tests that measure
electrical equipment require a circuit network that can
simulate the impedance of a human body. The
impedance of a human body varies with the contact
points, area and the path of conduction. Thus the
circuit network used to simulate the impedance of a
human body varies with the type of test performed. As
such, the safety standards used to measure leakage
current also varies greatly. The circuit networks used
are known as measuring devices, or MD for short. MD