ES601Plus OPERATING MANUAL
2.1.8 Patient Leakage Current
In this test, ES601Plus measures the current that flows out of the patient applied parts of the DUT though
the human body load when the parts are either connected to protective earth (normal condition), or to an
isolated AC voltage via a current-limiting resistor (MAP - Mains on Applied Part test). For the IEC60601
standard, the isolated voltage connected to the applied parts is equal to 110% of the AC line voltage
supplying the DUT; for other safety standards the isolated voltage is equal to the AC line voltage. As with
all leakage tests, patient leakage current is measured in microamps, while simulating various conditions at
the DUT.
In addition to specifying the individual test cases, the patient leakage measurement requires the applied parts
to be tested in related "functional groups". Such groups are classified as "body" (Type B), "body-floating"
(Type BF) or "cardiac-floating" (Type CF). "Type B" parts are not isolated and have the least stringent
safety requirements; "Type CF" parts are isolated and have the most stringent safety requirements since they
are intended for cardiac application; "Type BF" parts are also isolated but associated safety requirements are
less stringent than for cardiac "Type CF" parts.
ES601Plus allows up to five groups of applied parts to be defined, where each group can be a different
"Type" and can include from one to ten parts. Groups can be assigned names, as can the individual parts
within a group. A group of parts may also be "disabled", and therefore excluded from the test.
The way in which patient leakage must be measured is highly dependent on the specified group "Type". If
the safety standard is IEC60601, and an applied part group is designated "Type CF", then the leakage
current produced by each patient connection within that group is measured individually in turn. For an
applied part group which is "Type B" or "Type BF", all patient leads of the group are connected together
and then the collective leakage of the group of leads is measured. In accordance with the Third Edition of
the standard, if testing Mains on Applied Part (MAP) of a specific group of patient connections, then any
other applied part groups provided by the DUT that are not being MAP-tested must be connected to
protective earth. If testing "Type CF" defibrillator paddles in accordance with the IEC60601-2-4 standard,
then collective leakage of the paddles is measured, but only when performing the MAP test. For this special
case, a higher leakage is permitted than is otherwise allowed under the general standard.
For VDE-0751 and IEC62353 standards, patient connections are also tested in functional groups, however,
collective leakage of each group is always measured regardless of the group "Type". For AAMI standard,
collective leakage is measured for patient source current, but then is measured individually from each lead
for patient sink current.
The complicated details of testing patient leakage are managed automatically by ES601Plus, simply by
making a choice of safety standard and selecting an appropriate "Type" for each different group of patient
connections provided by the DUT (ECG; invasive blood pressure; temperature; SpO2; and so on). Setting
up ES601Plus to perform patient leakage measurements is relatively simple and is further explained in
section 5.10.
Overview/Chapter 2 # Page 13
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