Protection Relays and Controls
© 2016 Littelfuse Protection Relays & Controls
CT1 CT2
L2
L1
GROUNDED
AC SUPPLY
EL731 SERIES
(AC/DC Sensitive
Earth-Leakage Relay)
A
B
C
CT1
L2
L1
EL731 SERIES
(AC/DC Sensitive
Earth-Leakage Relay)
GROUNDED
DC SUPPLY
+
–
Description
The EL731 is
a microprocessor-based AC/DC Sensitive
Earth-Leakage Relay that offers complete coverage for all
frequencies from 0 to 6,000 Hz. Two CTs are required for the
entire frequency range, or one CT can be used for only low- or
high-frequency detection. An RTD/PTC sensor input allows
over-temperature protection for a motor or drive. The EL731
offers metering, password-protected alarm and trip settings
and optional network communications. It is primarily used to
add low-level ground-fault protection to variable-speed drives,
and to dc circuits.
EL731 SERIES
AC/DC Sensitive Earth-Leakage Relay
ORDERING NUMBER CONTROL
POWER COMMUNICATIONS
EL731-00-X0 120/240 Vac/Vdc None
EL731-01-X0 120/240 Vac/Vdc DeviceNet™
EL731-02-X0 120/240 Vac/Vdc Profibus®
EL731-03-X0 120/240 Vac/Vdc EtherNet/IP™
EL731-04-X0 120/240 Vac/Vdc Modbus® TCP
EL731-10-X0 48 Vdc & 24 Vac None
EL731-11-X0 48 Vdc & 24 Vac DeviceNet™
EL731-12-X0 48 Vdc & 24 Vac Profibus®
EL731-13-X0 48 Vdc & 24 Vac EtherNet/IP™
EL731-14-X0 48 Vdc & 24 Vac Modbus® TCP
EL731-20-X0 24 Vdc None
EL731-21-X0 24 Vdc DeviceNet™
EL731-22-X0 24 Vdc Profibus®
EL731-23-X0 24 Vdc EtherNet/IP™
EL731-24-X0 24 Vdc Modbus® TCP
Ordering Information
Simplified Circuit Diagram
ACCESSORIES REQUIREMENT
EFCT Series CT One Required
AC700-CUA Series Com. Unit Optional
AC700-SMK Surface-Mount Kit Optional
AC700-CVR-00 Watertight Cover (IP66) for
Panel-Mount Applications Optional
PGA-0520 Analog Meter Optional
Accessories
EFCT Series Earth-Fault Current
Transformer
Required zero-sequence current transformer
specifically designed for low level detection.
A
A A
A
AC Mode DC Mode
Earth-Leakage Protection–Grounded AC or DC Systems
Rev: 4-F-040716
Based on Manual Rev 6-F-031116
Littelfuse.com/el731
Note: When building a part number, replace the “X” with “1” for AS/NZS 2081:2011 Compliant product, “0” otherwise.
AC700-CUA Series
Communication Adapter
Optional network-interface and firmware-
upgrade communications adapters field-install
in EL731.
AC700-SMK DIN-rail & Surface-mount Adapter
EL731 plugs into adapter for back-plane
mounting.
For detailed wiring diagram, see adjacent page.
Protection Relays and Controls
© 2016 Littelfuse Protection Relays & Controls
14 L1 L2/N
GND
NC
TC
TB
TA
TC
TB
TA
TC
PTC RTD
PGA-0520
4-20mA
EFCT-X
EFCT-X
SUPPLY
t˚
+t˚ TB
TA
AB
AA
ANALOG
OUT
REMOTE
RESET
RTD/PTC
LINE 2/NLINE 1 OPTIONAL
NETWORK
COMM
FAULT
20-6000 HZ CT
DC-90 HZ CT
RST
GND
SH1
S12
S11
SH2
S22
S21
19
K1
22
25
K2
K3
20
16
15
18
21
23
24
26
17
2
1
5
4
3
11
10
9
8
7
6
13
12
AC/DC SENSITIVE
EARTH-LEAKAGE RELAY
EL731
+ –
Specifications
IEEE Device Numbers AC ground fault (50G/N, 51G/N),
DC ground fault (79G),
PTC overtemperature (49),
RTD temperature (38, 49)
Supply Voltage 120/240 Vac/Vdc, 24 Vdc,
48 Vdc/24 Vac
Trip Level Settings 30-5,000 mA AC and DC
Alarm Level Settings 30-5,000 mA AC and DC
Trip Delay 0.05-2 s
Output Contacts 3 Form C (programmable)
Contact Operating Mode Fail-safe & non-fail-safe
Reset Front panel and remote
Freq. Response, CT1 0-90 Hz
Freq. Response, CT2 20-6,000, 190-6,000, 20-90, 20-3,000 Hz;
selectable
Current Transformer EFCT-x series
CT Detection Open & short detection
Terminals Plug-in, wire clamping,
24 to 12 AWG (0.2-2.5 mm2)
Communications EtherNet/IP™, DeviceNet™, Profibus®,
Modbus® TCP (optional)
Analog Output 4-20 mA (selectable 0-5 A or
0-100% trip-level setting)
Conformal Coating Standard feature
Dimensions H 48 mm (1.9”); W 96 mm (3.8”);
D 129 mm (5.0”)
Approvals UL Listed (E340889), CSA,
RCM (Australia), CE
Warranty 5 years
Mounting Panel; Surface and DIN (with optional
AC700-SMK)
FEATURES BENEFITS
Adjustable pickup (30-5,000 mA) Adjustable trip setting provides a wide range of low-level protection and system coordination
Frequency range (0-90 Hz, 20-6,000 Hz) Operate in either AC or DC mode or both. Use single or combined ranges. Separate metering
32-char OLED display Earth-leakage metering, setup and programming
Local LED indication Visual Trip, Alarm, CT connection indication
CT-Loop monitoring Alarms when CT is not connected
Analog output (4-20 mA) Connect to DCS. Allows connection to an optional meter (PGA-0520) or control system
Adjustable time delay Adjustable trip delay for quick protection and system coordination
Alarm and trip settings Detect a deteriorating condition before damage occurs
Temperature-sensor input Drive or motor temperature protection
Output contacts 3 programmable: Operate 2 alarm and 1 trip circuit
Network communication Optional connection to plant network
Harmonic filtering Eliminates nuisance tripping due to harmonic noise
Microprocessor based No required calibration saves maintenance cost
Universal power supply Provides flexibility for numerous applications
Features & Benefits
Wiring Diagram
Earth-Leakage Protection–Grounded AC or DC Systems
EL731 SERIES
AC/DC Sensitive Earth-Leakage Relay
Littelfuse reserves the right to make product changes, without notice. Material in this document is as accurate as known at the time of publication. Visit Littelfuse.com for the most up-to-date information.
Littelfuse.com/el731
Rev: 4-F-040716
Based on Manual Rev 6-F-031116
