Fluke Biomedical DALE601 - Manual (Page 34)

DALE601/601E
Operators Manual
2-10
Measuring Leakage Current
Leakage current is the flow of current through or over the surface of an
insulating material or insulator. Leakage current is caused by the proximity of
the hot wire or line potential components to the chassis. In Figure 2-1, this
relationship is represented by Z
L
, a combination of capacitance (C
L
) and
resistance (R
L
) components. For example, if a person comes in contact with an
operational device, leakage current flows from the contact point, through the
person’s body, and back to ground. Measurement of leakage current is required
on all mains power products.
Earth Leakage Current
Earth Leakage Current (I
E
) (internal chassis current) flows in the ground wire
of the power cable to return the chassis leakage current to true earth ground.
This current is not a hazard if the ground wire remains intact and the current
does not become excessive. This leakage can occur if a major fault results in
the ground wire sharing the load current with the neutral wire or in supplying
the total return. The measurement is made using the 1000
Ω AAMI load
placed directly in series with the ground wire. Open neutral usually represents
the worst case.
To measure earth leakage current:
Note
Earth leakage current flows normally in the ground wire of the
device. This test is applicable only to devices using three-wire
(grounded) power cords.
1. Set the FUNCTION switch to EARTH LEAKAGE .