Standard 3+1 Protection Structure for TN-S and TT Three-Phase Systems

Product Overview

The NPS01-FBC7 AC 3+1P Surge Protective Device is a Type 1+2 combined surge protection unit designed for three-phase four-wire power distribution systems. It complies with EN/IEC 61643-11 and GB/T 18802.11 standards and meets Type 1+2 / Class I+II protection requirements.

The product adopts a standard 3+1 structure consisting of three phase modules and one neutral protection module. The L1/L2/L3 phases provide individual protection to ground, while the N-PE circuit uses a dedicated discharge module, making it highly compatible with TN-S and TT grounding systems.

With a 72mm width and 35mm DIN rail installation design, the device supports Uc voltage levels from 275V to 440V. It is widely used at the incoming power side of buildings, communication rooms, data centers, and electrical distribution systems.

Dedicated N-PE Spark Gap for Zero Leakage Neutral Protection

The phase protection circuit combines graphite spark gaps with zinc oxide varistors, while the N-PE path uses a dedicated graphite discharge module. Under normal operating conditions, the neutral line maintains extremely low leakage current and power consumption, helping prevent abnormal neutral voltage rise.

Each protection module features independent thermal disconnection for enhanced safety. High-quality components are selected for excellent resistance to temperature, humidity, and aging.

The conductive system uses high-purity T2 copper busbars with tin-plated surfaces, providing low resistance, strong current carrying capability, and reduced heat generation.

The UL94V-0 flame-retardant housing offers reliable insulation protection. Automated welding, module assembly, and complete factory testing ensure long-term operating stability.

Independent Module Protection with Reliable Fault Isolation

This series provides 7kA (10/350μs) lightning impulse current capability, 20kA (8/20μs) nominal discharge current, and 50kA maximum discharge current. The voltage protection level is as low as 1.2kV, with response time ≤25ns (100ns in NPE mode).

Each module includes thermal disconnection and a red/green status indicator. Green indicates normal operation, while red indicates that the corresponding module requires replacement.

The device supports optional remote alarm contacts with AC 250V/0.5A capacity and 0.5-1.5mm² wiring. It operates from -40℃ to +80℃ under 5%-95% humidity conditions and supports 4-25mm² conductors.

With high reliability and flexible monitoring options, it is an effective protection solution for three-phase four-wire electrical systems.

Model	NPS01-FBC7/275/3+1	NPS01-FBC7/320/3+1	NPS01-FBC7/385/3+1	NPS01-FBC7/440/3+1
SPD Test Category	Type1+2/ClassI+II(EN/IEC61643-11, GB/T18802.11)
Maximum Continuous Operating Voltage Uc (Current Type: a.c.)	2275V(NPE255V)75V	320V(NPE255V)	385V(NPE255V)	440V(NPE255V)
Lightning Impulse Current (10/350μs) [L-PE, N-PE] Iimp	7kA	7kA	7kA	6.25kA
Nominal Discharge Current (8/20μs) [L-PE, N-PE] In	20kA
Maximum Discharge Current (8/20μs) [L-PE, N-PE] Imax	50kA
Voltage Protection Level [L-PE, N-PE] Up	1.2kV	1.3kV	1.5kV	1.7kV
Response Time	≤25ns (N-PE: 100ns)
Backup Fuse	100A gG Fuse
Remote Signal Alarm	Normally Open and Normally Closed Contact Terminals
Remote Alarm Signal Energy Un/In	AC: 250V/0.5A; 125V/1A; DC: 30V/0.1A
Remote Alarm Signal Connection Wire	0.5mm² to 1.5mm²
Remote Contact Type	Floating Changeover Contact
Temperature and Humidity Range	-40℃ to +80℃, 5%~95%
Disconnector Operation Indicator	Red: Failed; Green: Normal
Minimum Installation Conductor Cross-Section Area (L, N, PE)	4mm² Solid Wire / Flexible Wire
Maximum Installation Conductor Cross-Section Area (L, N, PE)	25mm² Standard Wire / Flexible Wire
Installation Method	35mm Standard DIN Rail
Enclosure Material	Red Thermoplastic Material, UL94V-0
Enclosure Protection Degree	IP20
Dimensions	W×L×H: 72×87×87mm
Note: The above products can be optionally equipped with a remote signaling function. Products with remote signaling will have "/FM" added after the original model number, such as NPS01-FBC7/275/1/FM.