Ampcontrol Pty Ltd
– ABN 28 000 915 542
EFL PROTECTION RELAY USER MANUAL
MAG-178 Version 5
– MARCH/2020
Uncontrolled Copy - Refer to Ampcontrol Website for Latest Version
Page 8 of 23
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PRODUCT OVERVIEW
3.1 Product Description
The Ampcontrol EFL Protection Relay provides earth fault lockout (EFLO) and frozen contactor (FC)
protection that is compliant to AS/NZS 2081:2011 sections 7 & 9.
While the outlet’s main contactor is open, the EFL will continually monitor the resistance of the phase
conductors to earth, on the load side of the contactor. If this resistance falls below an acceptable level,
then the EFL will initiate an EFLO trip, preventing the outlet from being started.
The EFL will also monitor the state of the outlet’s main contactor. If voltage appears on the line when the
contactor is open, a Frozen Contactor electrical trip will occur, opening the CBR output. If the main
contactor is either open when it should be closed or closed when it should be open a Frozen Contactor
logical trip will occur, opening the CBR relay. The CBR relay is intended to be used to open the
upstream circuit breaker. A back EMF timer is also provided to inhibit the frozen contactor electrical trip
function for a short period after the main contactor is open.
The EFL also has an undervoltage protection function which, if activated, will open the main contactor if
the voltage on the load side of the contactor falls below 50% of the selected system voltage.
The EFL is available in two configurations, an internal barrier configuration and an external barrier
configuration. If using the internal barrier unit, the high voltage connection leads will extend directly from
the EFL Relay. If using the external barrier version, the high voltage connection barrier is stored inside a
separate enclosure, allowing the barrier to be installed closer to the phase conductors if required. This
external barrier is supplied with ‘flying leads’ for connection to the phase conductors. The external barrier
is then required to be wired to a stand-alone EFL Relay (no internal barrier).
Key Features
AS/NZS 2081:2011 compliant
Earth Fault Lock-out (EFLO) protection
Frozen Contactor (FC) protection
Selectable Undervoltage (UV) protection
Compatible with a wide range of system voltages
Internal or external barriers available
3.2 Applications
The Ampcontrol EFL is compliant to AS/NZS 2081:2011 sections 7 & 9, and has been designed for
installation on mining outlets that require earth fault lockout and frozen contactor protection. The EFL is
capable of being installed on a wide range of system voltages from 110V up to 1.1kV (barrier
dependent). In addition to EFLO and FC protection, the EFL also offers a selectable undervoltage
protection function.
NOTE
The EFL Relay is not for use in hazardous areas. Customers should
select the EFL-IS (available in 2016) or OMA products for applications
requiring intrinsic safety.
For a typical electrical installation diagram, refer to Figure 4.6.
