Ampcontrol Pty Ltd – ABN 28 000 915 542
OCS USER MANUAL
MAG-182 Version 5 – FEB/2020
Uncontrolled Copy - Refer to Ampcontrol Website for Latest Version
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7 AS/NZS 2081:2011 PROTECTION FUNCTIONS
The Protection Element, housed within the Cassette, provides a number of protection functions that meet
the requirements of the AS/NZS 2081:2011 standard. This protection functions are:
Earth Leakage*
Earth Continuity
Earth Fault Lockout
Main Contactor Fail
* - Not Available on Residual Voltage OCS Protection Element
7.1 Earth Leakage
7.1.1 Trip Characteristics
Table 5: Protection Element - Earth Leakage Trip Characteristics
Requires an earth leakage reset after the trip condition has cleared
Open Main Contactor
Prevent Main Contactor from closing
Earth Leakage current displayed as 0-150% of selected trip level
7.1.2 Operation Summary
The earth leakage protection function uses an Ampcontrol EL500 series toroid to measure the earth
fault current. This function is tested to AS/NZS 2081:2011. A definite time operating characteristic is
provided with adjustable trip sensitivity and an adjustable time delay.
Due to size restrictions and the coupling issues related with elongated
current transformers, the Ampcontrol EL500 series earth leakage toroid
is not integral to the Cassette and must be purchased separately.
When a fault occurs such that the trip level and time delays are exceeded, a trip occurs. The trip acts in
the Main Contactor Relay (MCR) logic and is latched. An earth leakage trip is considered a special fault
and requires a specific reset function to be cleared.
The earth leakage current (EL) is displayed as a % of the trip level. When the leakage reaches 100%
for the selected time delay a trip occurs.
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