EEC SE 7430, User Manual

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powered up immediately after the safety tests are completed with a single connection to the DUT.
Measurements that are commonly made while the DUT is running can include Amperage, Voltage,
Watts and Power Factor.
1.5.5 Touch Current Test
The Line Leakage test is one of many product safety tests that are normally specified for electrical
products by safety testing agencies such as Underwriters Laboratories (UL) and the International
Electrotechnical Committee (IEC). The line leakage specifications vary as well as the method in
which the measurements are taken depending upon the application or function of a product and
the standard to which the product is being tested.
Current Leakage or Line Leakage tests are general terms that actually describe three different
types of tests. These tests are Earth Leakage Current, Enclosure Leakage Current, and Applied Part
Leakage Current. The main differences in these tests are in the placement of the probe for the
measuring device. The Earth Leakage Current is the leakage current that flows through the ground
conductor in the line cord back to earth. The Enclosure Leakage Current is the current that flows
from any enclosure part through a person back to ground if it were contacted by a person. The
Applied Part Leakage Current or Patient Lead Leakage Current is any leakage that flows from an
applied part, between applied parts or into an applied part. The Applied Part Leakage Current test
is required only for medical equipment. All of these tests are used to determine if products can be
safely operated or handled without posing a shock hazard to the user.
Line Leakage Testers provide the capability of meeting the line leakage test specified in the
following standards; UL 544, IEC 950, UL 1950, IEC 601-1, UL 2601, UL 1563, UL 3101, IEC 1010 and
others. The Line Leakage test, is a test which measures the leakage current of a product, through a
circuit that is designed to simulate the impedance of the human body. The simulation circuit is
called the Measuring Device (MD). The instrument has five different MD circuits, selectable
through the menu, which are representative circuits designed to simulate the impedance of the
human body under different conditions. The impedance of the human body will vary depending
upon point of contact, the surface area of the contact and the path the current flows. For these
reasons, the specifications of the Measuring Devices are different depending upon the type of test
being performed as well as the maximum allowable leakage current. Leakage current
measurements are performed on products under normal conditions and single fault conditions as
well as reversed polarity. This simulates possible problems, which could occur if the product under
test is faulted or misused while the product is operating under high line conditions (110% of the
highest input voltage rating of the product).
Line Leakage tests are normally specified as “Type Tests” or “Design Tests” which are performed
during the development of the product. This helps verify that the design is safe but it does not
guarantee the safety of the products being produced on the production line. The only way to be
sure you are shipping safe products is to test each product at the end of the production line. The
user may perform a Leakage Current test along with other common safety test such as Dielectric
Withstand, Insulation Resistance, and Ground Bond on the production line with a single
connection to the device under test.