Selec 900EFR Earth Fault Relay
Selec 900EFR-BL-U Earth Fault Relay (1Ø/3Ø, True RMS, Dual Relay Output)
A True-RMS earth fault monitoring relay for 1-phase and 3-phase systems with adjustable trip settings, dual relays, LCD backlight, test/reset capability, and DIN-rail mounting.
The Selec 900EFR-BL-U is a true RMS earth fault monitoring relay designed for 1-phase and 3-phase electrical systems. It provides precise fault detection with adjustable trip settings, dual alarm relays, LCD backlight, and selectable auto/manual reset. Ideal for MCCB-based protection systems, it supports DIN-rail mounting and wide auxiliary supply input.
Key Features
Earth fault monitoring for 1Ø (2-wire) and 3Ø (3-wire/4-wire) systems
True RMS measurement for high accuracy
Adjustable trip setting: 10–80% of MCCB frame rating
Dual relay output: 2× SPDT, selectable NC/NO operation
LCD display with backlight
Adjustable power-on delay, trip delay & recovery delay
Remote and front Test/Reset function
Hysteresis adjustable from 1 to 10%
Fast response time (<100 ms)
Wide auxiliary supply: 85–270V AC/DC
DIN-rail mount (35mm)
Technical Specifications
| Parameter | Specification |
|---|---|
| Measurement Type | Earth Fault Monitoring |
| System Compatibility | 1Ø-2W, 3Ø-3W, 3Ø-4W |
| CT Frame Ratings | 160A, 250A, 630A |
| Trip Setting (Earth Fault) | 10–80% of MCCB frame rating |
| Power-On Delay | 0.5–99.9 sec |
| Trip Time Delay | 0–99.9 sec |
| Recovery Time Delay | 0–99.9 sec (Auto reset mode) |
| Response Time | <100 ms |
| Hysteresis | 1–10% of fault current |
| Current Resolution | 0.1A (≤99.9A), 1A (>100A) |
| Accuracy—Current | ±5% of setting ±2 digits |
| Accuracy – Time | ±5% of setting ±100 ms |
| Relay Outputs | 2× SPDT (5A NO, 3A NC @ 250V AC) |
| Aux Supply | 85–270V AC/DC |
| Operating Temperature | 0°C to +50°C |
| Protection | IP20 |
| Display | LCD with backlight |
| Mounting | DIN rail |
| Weight | 150 g |
| Dimensions | 90×35×70.5 mm |
Applications
MCCB-based feeder protection
Industrial control panels
Motor control centers (MCC)
Power distribution boards
AC/DC power systems with earth fault monitoring
Safety circuits in manufacturing & automation
Generator and transformer protection panels
What’s in the Box?
Selec 900EFR-BL-U Earth Fault Relay
User manual / datasheet
Warranty information (if provided)
FAQ
Q1: Does the 900EFR-BL-U require an external CT?
Yes, it must be paired with an EFCT (Selec earth fault CT) such as 160/1A, 250/1A, or 630/1A.
Q2: Can I use it on both 1-phase and 3-phase systems?
Yes, it supports 1Ø-2W, 3Ø-3W, and 3Ø-4W wiring.
Q3: What is the auxiliary supply range?
Wide range of 85–270V AC/DC, as per datasheet Page 1.
Q4: Are the relay outputs NO or NC?
Both relays are SPDT, and NO/NC operation is selectable.
Q5: What is the typical response time?
Less than 100 ms.
Q6: Does it support remote reset?
Yes, both front panel and remote reset are supported.