Legrand 026088 Differential Relay for DPX and DPX³ Circuit Breakers Instruction Manual

1. Introduction and Overview

This instruction manual provides essential information for the installation, operation, and maintenance of the Legrand 026088 Differential Relay. This device is designed to enhance the safety and protection of electrical installations by adding differential current detection capabilities to Legrand DPX and DPX³ circuit breakers.

The differential relay detects earth fault currents and, in conjunction with a suitable trip unit (current emission or undervoltage release), commands the associated circuit breaker to trip, thereby protecting personnel and equipment from electrical hazards.

2. Product Features

• Differential Current Detection: Designed to detect insulation fault currents between phase and earth.
• Compatibility: Integrates with Legrand DPX and DPX³ circuit breakers equipped with a trip unit.
• Auxiliary Contact: Includes an auxiliary contact for remote signaling or interlocking.
• Visual Indicators:
  • Green LED: Indicates power supply status.
  • Three Yellow LEDs: Indicate the maximum fault current quantity (20%, 40%, and 60% of the set value).
  • Red LED (Fixed): Indicates that the insulation fault current value has been exceeded.
  • Red LED (Flashing): Indicates a break in one of the connections between the current transformers (toroids) and the relay.
• Sealable Window: Equipped with a foldable and sealable window for secure settings.
• Compact Design: 2-module width, suitable for rail mounting.

3. Safety Information

WARNING: Electrical installations should only be performed by qualified and authorized personnel. Failure to follow these instructions can result in serious injury or death.

• Always disconnect power to the circuit before installing, servicing, or removing the device.
• Ensure all connections are secure and correctly wired according to local electrical codes and standards.
• Do not operate the device if it appears damaged or if any parts are missing.
• Verify the voltage and current ratings of the relay and associated circuit breakers are compatible with the electrical system.
• Regularly test the differential relay as per local regulations and manufacturer recommendations.

4. Setup and Installation

The Legrand 026088 Differential Relay is designed for easy installation on a DIN rail or chassis mounting within an electrical panel.

Figure 1: Legrand 026088 Differential Relay. This image shows the compact, 2-module device with its various indicators and adjustment dials, designed for integration into an electrical panel.

4.1 Mounting

1. Ensure the power supply to the installation is completely isolated.
2. Clip the differential relay onto a standard DIN rail or secure it using chassis mounting points within the electrical enclosure.
3. Ensure adequate ventilation around the device.

4.2 Wiring

1. Connect the power supply (230V/240V - 50/60 Hz) to the designated terminals on the relay.
2. Connect the current transformers (toroids) to the relay. Ensure correct polarity and secure connections. A flashing red LED indicates a connection break.
3. Connect the auxiliary contact to the desired signaling or interlocking circuit, if applicable.
4. Connect the output of the differential relay to the trip unit (current emission or undervoltage release) of the associated DPX or DPX³ circuit breaker.
5. After wiring, double-check all connections for tightness and correctness.

4.3 Initial Configuration

1. Set the desired differential current sensitivity and time delay using the adjustment dials on the front panel. Refer to local regulations and system requirements for appropriate settings.
2. Close the foldable and sealable window to protect the settings from unauthorized changes.

5. Operating Instructions

Once installed and configured, the Legrand 026088 Differential Relay operates automatically to monitor for earth fault currents.

5.1 LED Indicators

• Green LED: Illuminates when the relay is powered on and functioning correctly.
• Yellow LEDs (20%, 40%, 60%): These LEDs illuminate progressively to indicate the magnitude of the detected insulation fault current relative to the set trip threshold. For example, if the fault current reaches 40% of the threshold, the 20% and 40% LEDs will be lit.
• Red LED (Fixed): A continuously lit red LED indicates that an insulation fault current exceeding the set threshold has been detected, and the relay has initiated a trip command to the circuit breaker.
• Red LED (Flashing): A flashing red LED indicates a break in the connection between the current transformers (toroids) and the differential relay. This condition requires immediate attention as the differential protection may be compromised.

5.2 Test and Reset Functions

• Test Button: Pressing the "Test" button simulates an earth fault condition to verify the proper functioning of the relay and the associated circuit breaker trip mechanism. This test should be performed periodically as per safety regulations.
• Reset Button: After a trip due to an earth fault, the relay may need to be manually reset using the "Reset" button once the fault has been cleared and the circuit breaker has been reclosed.

6. Maintenance

The Legrand 026088 Differential Relay is designed for reliable operation with minimal maintenance. However, periodic checks are recommended to ensure continued performance and safety.

• Visual Inspection: Periodically inspect the device for any signs of physical damage, discoloration, or loose connections.
• Functionality Test: Regularly perform the "Test" button function to ensure the relay and the associated circuit breaker trip correctly. The frequency of this test should comply with local electrical safety standards.
• Cleaning: If necessary, gently clean the exterior of the device with a dry, soft cloth. Do not use abrasive cleaners or solvents. Ensure power is disconnected before cleaning.
• Connection Integrity: Check that all wiring connections remain tight and secure.

7. Troubleshooting

This section provides guidance for common issues encountered with the differential relay.

8. Specifications

9. Warranty and Support

Specific warranty terms and conditions for the Legrand 026088 Differential Relay are provided by the manufacturer, Legrand, or your authorized seller at the time of purchase. Please retain your proof of purchase for warranty claims.

For technical support, service, or further information, please contact your local Legrand representative or visit the official Legrand website. Always refer to the latest product documentation and safety guidelines provided by Legrand.