EL731-02-10 - EL731 Series – Earth-Leakage, Ground-Fault Relay Series

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Disclaimer Notice

Littelfuse products are not designed for, and shall not be used for, any purpose (including, without limitation, automotive, military, aerospace, medical, life-saving, life-sustaining or nuclear facility applications, devices intended for surgical implant into the body, or any other application in which the failure or lack of desired operation of the product may result in personal injury, death, or property damage) other than those expressly set forth in applicable Littelfuse product documentation. Warranties granted by Littelfuse shall be deemed void for products used for any purpose not expressly set forth in applicable Littelfuse documentation. Littelfuse shall not be liable for any claims or damages arising out of products used in applications not expressly intended by Littelfuse as set forth in applicable Littelfuse documentation. The sale and use of Littelfuse products is subject to Littelfuse Terms and Conditions of Sale, unless otherwise agreed by Littelfuse. "Littelfuse" includes Littelfuse, Inc., and all of its affiliate entities.

The EL731 series relay operates on ac resistance-grounded systems and dc grounded systems. This unit is a microprocessor-based ac, dc, sensitive, earth-leakage relay that offers complete coverage for all frequencies from 0–6,000 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 temperature sensor input allows over-temperature protection. The EL731 offers metering capabilities, password-protected alarm and trip settings, and optional network communications. The EL731 is used to add low-level ground-fault protection to variable-speed drives and to dc currents.

Computer-to-Relay Connection
Connect the EL731 to the network using a standard Ethernet patch cable. Use of a crossover cable to connect the EL731 directly to the computer running IP-Config is not recommended. A typical router will assign an IP address to all connected computers that are using DHCP. The EL731 does not support the use of DHCP. If the EL731 is being set up for first time, it is recommended to only have one EL731 connected to the network to prevent communication errors.


  • Adjustable pickup (30–5,000 mA)
  • Frequency range (0–90 Hz, 20–6,000 Hz)
  • 32-character OLED display
  • Local LED indication
  • CT-loop monitoring
  • Analog output (4–20 mA)
  • Adjustable time delay
  • Alarm and trip settings
  • Temperature sensor input
  • Output contacts
  • Network communication
  • Harmonic filtering
  • Microprocessor-based
  • Universal power supply
Property (Mouseover for details) Value
Communications DeviceNet
Relay Contacts Config 3 Form C (N.O./N.C.)
Supply Voltage ac 120 / 240
Supply Voltage dc 120 / 240
IEEE Device Numbers 38 - 49 - 50G - 50N - 51G - 51N - 79G
Relay Contacts Operation Fail-safe / Non Fail-safe
Dimensions 1.9 H x 3.8 W x 5 D in.
Weight (lbs/g) 0 Kg
Auto Manual Reset Latching trip - Non-latching alarm
Conformally coated Standard
Frequency 0 - 6000
GF Trip Level A 0.03 - 5.00
GF Trip Time s 0.05 - 2.00
Harmonic Filtering Standard
Mount Method DIN (optional) - Panel - Surface (optional)
Reset Type Front-panel switch/Remote N.O. Contact
System type Solidly Grounded AC - Solidly Grounded DC - Resistance rounded AC
Temp Sensor Config Single PTC/RTD
Check Stock Yes
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