FCP18-02
Three-Phase Voltage & Phase Sequence Protection Relay
Over-voltage, Under-voltage & Phase Protection in One Compact Module
The FCP18-02 is a precision three-phase voltage monitoring relay combining three essential protection functions — over-voltage, under-voltage, and phase sequence/loss detection — in a single ultra-compact 18mm DIN rail module. Designed for industrial motor protection and power distribution applications where asymmetric voltage detection is not required.
Compared with the FCP18-03 and FCP18-04, the FCP18-02 is a streamlined solution offering fast over/under voltage protection combined with phase sequence and loss detection, without the asymmetry monitoring function. This makes it an ideal cost-effective choice for applications where phase imbalance is not a primary concern, such as simple motor starters, pump panels, and basic power distribution monitoring.
Quick Specifications
Why Choose the FCP18-02?
Engineered for industrial reliability with focused over-voltage, under-voltage, and phase protection.
3-in-1 Protection
Over-voltage, under-voltage, and phase sequence/loss — the three most critical faults covered in one compact DIN rail module.
±1% Measurement Accuracy
Electronic voltage sensing circuit ensures stable, repeatable protection with minimal drift across temperature and load variations.
16A SPDT Output Relay
High-capacity SPDT output handles direct motor and contactor switching. Mechanical life 10 million cycles, electrical life 100,000 cycles.
Tool-Free Configuration
Four front-panel adjustment buttons (Un, U>, U<, Tt) allow fast, screwdriver-free setup. No programming or software tools required.
0.1~30s Adjustable Delay
Configurable time delay from 0.1s to 30s adapts to both fast-trip requirements and motor starting conditions.
Three Protection Functions
Focused monitoring of the three most critical three-phase fault conditions — no asymmetry function for streamlined protection.
The FCP18-02 monitors three fault conditions simultaneously. The diagram below illustrates the over-voltage and under-voltage operating regions. The relay trips when the measured voltage exceeds the set threshold (U>) or drops below the set threshold (U<) and holds for the configured time delay (Tt).
The phase sequence and phase loss function monitors the L1, L2, L3 phase order and immediately detects when any phase is interrupted or reversed. The FCP18-02 does not include voltage asymmetry monitoring — for asymmetry protection, see the FCP18-03 (fixed 8%) or FCP18-04 (5%~15% adjustable).
1. Over-voltage Protection (U>)
When the measured line voltage rises above the adjustable over-voltage threshold (U>) — set between +2% and +20% above the rated voltage (Un) — and remains high for the configured time delay (Tt), the relay trips and opens the output contact. This protects connected equipment from dangerous overvoltage conditions caused by generator overspeed, load rejection, or grid surges.
- Trip threshold: Un + (U> dial % of Un)
- Time delay: Tt setting (0.1s to 30s) must elapse before trip is confirmed
- Reset: Automatic reset once voltage returns to normal
2. Under-voltage Protection (U<)
When the measured line voltage falls below the adjustable under-voltage threshold (U<) — set between −2% and −20% below the rated voltage (Un) — and remains low for the configured time delay (Tt), the relay trips. This prevents motor stalling, overheating, and equipment damage caused by sustained low-voltage conditions from brownouts or overloaded distribution circuits.
- Trip threshold: Un − (|U<| dial % of Un)
- Time delay: Tt setting (0.1s to 30s) prevents nuisance tripping from brief voltage dips during motor starts
- Application: Essential for motor protection and compressor control systems
3. Phase Sequence & Phase Loss Protection
The FCP18-02 continuously monitors the rotational sequence of the three-phase supply (L1 → L2 → L3). If the phase sequence is reversed or any phase is interrupted (open circuit, blown fuse, or cable fault), the relay immediately detects the fault and trips. The red P LED on the front panel provides instant visual status: lit = correct sequence, flashing = fault detected.
- P LED lit (steady): All three phases present and in correct rotation sequence
- P LED flashing: Phase loss (one or more phases missing) or phase sequence reversed
- Trip behavior: Immediate — no additional time delay for phase loss/sequence faults
- Protection scope: Detects single-phase loss, two-phase loss, and reversed phase wiring errors
Technical Specifications
Full electrical and mechanical specifications for the FCP18-02 series.
| Parameter | FCP18-02A / 02C | FCP18-02B / 02D |
|---|---|---|
| System Type | 3-Phase 3-Wire (L1-L2-L3) | 3-Phase 4-Wire (L1-L2-L3-N) |
| Voltage Range (L-L) | 173-275V AC (A) / 310-480V AC (C) | N/A for 4-wire models |
| Voltage Range (L-N) | N/A for 3-wire models | 100-160V AC (B) / 180-278V AC (D) |
| Rated Frequency | 45Hz - 65Hz | 45Hz - 65Hz |
| Voltage Tolerance | −15% to +10% | −15% to +10% |
| Asymmetry Function | None | None |
| Over/Under Voltage Range | ±(2%~20%) adjustable | ±(2%~20%) adjustable |
| Time Delay (Tt) | 0.1s, 3s, 6s, 9s, 12s, 15s, 18s, 20s, 25s, 30s | 0.1s, 3s, 6s, 9s, 12s, 15s, 18s, 20s, 25s, 30s |
| Measurement Accuracy | ΔV less than ±1% | ΔV less than ±1% |
| Temperature Coefficient | 0.05%/°C at 20°C | 0.05%/°C at 20°C |
| Output Contact | 1 × SPDT (NO+NC) | 1 × SPDT (NO+NC) |
| Rated Current | 16A / 250V AC | 16A / 250V AC |
| Mechanical Life | 1 × 107 operations | 1 × 107 operations |
| Electrical Life | 1 × 105 operations | 1 × 105 operations |
| Ambient Temperature | −20°C to +60°C | −20°C to +60°C |
| Mounting | DIN Rail EN/IEC 60715 (35mm) | DIN Rail EN/IEC 60715 (35mm) |
| Dimensions (H × W × D) | 90 × 18 × 64 mm | 90 × 18 × 64 mm |
| Weight | 68g | 68g |
| IP Rating | IP20 | IP20 |
| Standards | GB/T 14048.5, IEC60947-5-1, EN61812-1 | GB/T 14048.5, IEC60947-5-1, EN61812-1 |
Voltage codes: A = 173-275V L-L (3-wire) | B = 100-160V L-N (4-wire) | C = 310-480V L-L (3-wire) | D = 180-278V L-N (4-wire). Other voltages available on request.
Terminal Connections
SPDT relay output with screw-clamp terminals for fast, reliable wiring.
FCP18-02A / 02C — 3-Phase 3-Wire (L1-L2-L3)
FCP18-02B / 02D — 3-Phase 4-Wire (L1-L2-L3-N)
- Always de-energize the panel before wiring
- Verify supply voltage matches the module rating before powering on
- Connect L1, L2, L3 (and N for 4-wire models) to the corresponding system phases
- Terminal 11 = Common, 12 = NC, 14 = NO — wire your load to the appropriate contact
- Use correct wire gauge for 16A load current (min. 1.5mm²)
- Tighten terminal screws to 0.4 N·m torque specification
- Stripping length: 7mm (AWG13-20)
Front Panel & Settings
Configure the FCP18-02 using four adjustment buttons — no software or programming tools required.
| Parameter | Description | Setting Range |
|---|---|---|
Un |
Rated Input Voltage (system voltage) — the nominal voltage of the three-phase installation | See voltage code table in Models section |
U> |
Over-voltage Trip Threshold — voltage above Un that triggers a trip | +2% to +20% of Un (adjustable) |
U< |
Under-voltage Trip Threshold — voltage below Un that triggers a trip | −2% to −20% of Un (adjustable) |
Tt |
Time Delay before trip — the delay period the relay waits before confirming a fault | 0.1s, 3s, 6s, 9s, 12s, 15s, 18s, 20s, 25s, 30s |
LED Indicator Panel
Un — Green LED
Lit = relay is powered on and monitoring the system
P — Red LED
Lit = correct phase sequence. Flashing = phase reversal). Off =phase loss
R — Red LED
Lit = NO contact (terminals 11-14) is closed, relay is energized
⚙ How to Set Parameters
- Enter setting mode: Press and hold the button until the LED starts flashing.
- Adjust dials: Set
Un,U>,U<, andTtto your desired values while the LED is flashing. - Confirm: Press and hold the button until the LED stops flashing to save your settings.
Note: When the green LED is on, add 1% to the over/under voltage dial reading to get the actual trip threshold. For example, if the U> dial reads 10% and the green LED is lit, the actual over-voltage trip point = Un + 11%.
Models & Ordering
Choose the voltage configuration that matches your three-phase system.
| Model Code | System Type | Voltage Range (L-L) | Voltage Range (L-N) | Manual |
|---|---|---|---|---|
| FCP18-02A | 3-Phase 3-Wire | 173, 190, 198, 208, 220, 230, 240, 250, 260, 275 V | N/A | PDF ↓ |
| FCP18-02B | 3-Phase 4-Wire | N/A | 100, 110, 115, 120, 127, 133, 139, 145, 151, 160 V | PDF ↓ |
| FCP18-02C | 3-Phase 3-Wire | 310, 328, 345, 365, 380, 400, 415, 440, 460, 480 V | N/A | PDF ↓ |
| FCP18-02D | 3-Phase 4-Wire | N/A | 180, 190, 200, 210, 220, 232, 240, 255, 266, 278 V | PDF ↓ |
FCP18 Family — Model Comparison
Compare all six FCP18 series models to find the right protection configuration for your application.
| Model | Over-voltage | Under-voltage | Asymmetry | Time Delay | Phase Seq. | Phase Loss | Ideal For |
|---|---|---|---|---|---|---|---|
| FCP18-01 | — | — | — | 5s fixed | ✓ | ✓ | Phase sequence/loss only, budget applications |
| FCP18-02 | 2%-20% Adjustable | 2%-20% Adjustable | — | 0.1~30s | ✓ | ✓ | OV/UV + phase protection — cost-effective motor & pump protection |
| FCP18-03 | 2%-20% Adjustable | 2%-20% Adjustable | 8% fixed | 0.1~30s | ✓ | ✓ | Full protection incl. fixed asymmetry — general motor & compressor |
| FCP18-04 | 2%-20% Adjustable | 2%-20% Adjustable | 5%~15% adj. | 5s fixed | ✓ | ✓ | Adjustable asymmetry sensitivity — CNC, medical, precision equipment |
| FCP18-05 | — | — | 5%~15% adj. | 0.1~30s | ✓ | ✓ | Asymmetry-only with adjustable sensitivity |
| FCP18-06 | 15% fixed | 15% fixed | 8% fixed | 5s | ✓ | ✓ | Asymmetry + phase protection, no OV/UV adjustment |
Configuration Examples
Real-world setting examples for common three-phase system voltages.
FCP18-02A — 208V System
| Un (Voltage) | 208V |
| U> (Over) | +10% = 228.8V |
| U< (Under) | −11% = 185.1V |
| Tt (Delay) | 0.1s (fast-trip) |
FCP18-02C — 400V System
| Un (Voltage) | 400V |
| U> (Over) | +10% = 440V |
| U< (Under) | −10% = 360V |
| Tt (Delay) | 12s (motor start tolerance) |
FCP18-02B — 120V System
| Un (Voltage) | 120V |
| U> (Over) | +10% = 132V |
| U< (Under) | −11% = 106.8V |
| Tt (Delay) | 3s |
FCP18-02D — 230V System
| Un (Voltage) | 230V |
| U> (Over) | +15% = 264.5V |
| U< (Under) | −8% = 211.6V |
| Tt (Delay) | 20s (heavy motor load) |
See It In Action
Watch the FCP18 series product overview and demonstration.
Typical Applications
The FCP18-02 protects three-phase equipment across a wide range of industrial sectors.
Motor Protection
Protect three-phase motors from over-voltage, under-voltage, phase loss, and reversal damage in pump and fan applications.
HVAC & Compressors
Protect compressors and HVAC equipment from mains voltage anomalies and phase faults.
Power Distribution
Panel-level monitoring in LV/MV switchgear and distribution boards.
Pump Panels
Cost-effective protection for water pump panels, irrigation systems, and booster stations.
Industrial Automation
General-purpose protection for PLC-controlled systems and automated industrial equipment.
Ready to Order or Need More Details?
Download the full technical manual or contact the FIICCO team for pricing, samples, and OEM options.
Frequently Asked Questions
Common questions about the FCP18-02 three-phase protection relay
The key difference is the asymmetry function: the FCP18-02 does not include voltage asymmetry (unbalance) monitoring, while the FCP18-03 provides fixed 8% asymmetry protection. The FCP18-02 focuses on the three most critical faults — over-voltage, under-voltage, and phase sequence/loss — making it a cost-effective choice for applications where voltage unbalance is not a primary concern. If you need asymmetry protection, see FCP18-03 (fixed 8%) or FCP18-04 (5%~15% adjustable).
Four voltage configurations are available: FCP18-02A (173-275V L-L, 3-wire), FCP18-02B (100-160V L-N, 4-wire), FCP18-02C (310-480V L-L, 3-wire), and FCP18-02D (180-278V L-N, 4-wire). Each model offers 10 preset voltage steps selectable via the Un dial. Other voltages are available on request.
The time delay setting depends on your application. For fast-trip protection without motor starting conditions (e.g., distribution panels, pure resistive loads), use a short delay such as 0.1s or 3s. For motor protection where inrush current causes brief voltage dips during startup, use a longer delay (e.g., 12s, 20s, or 30s) to prevent nuisance tripping. The adjustable 0.1~30s range covers both scenarios.
No. The FCP18-02 is specifically designed for three-phase systems and requires three-phase input (L1, L2, L3) to operate. For single-phase over/under voltage protection, consider a single-phase voltage monitoring relay from FIICCO's product range.
The FCP18-02 has a single SPDT (single-pole double-throw) relay contact rated 16A/250V AC. Terminal 11 is the common, 12 is normally closed (NC), and 14 is normally open (NO). Wire your load between terminal 11 and terminal 14 for normally open operation — the circuit is energized when the relay trips.
The FCP18-02 is certified to CE, RoHS, and meets the standards of IEC 60947-5-1, GB/T 14048.5, and EN 61812-1. This makes it suitable for industrial automation applications in Europe, Asia, and other global markets.
Yes. FIICCO provides OEM services including custom branding (logo, model number, color), tailored specifications, and custom packaging for orders of 100+ units. Factory-direct pricing ensures competitive costs for OEM customers. Contact us at info@fiicco.com with your requirements and quantity for a tailored quotation.