Mitsubishi NF1000-SEW | WS-V Series 1000A Standard Class MCCB
Electronic Trip, 85kA at 400V, 3-Pole & 4-Pole
Product Overview
The Mitsubishi NF1000-SEW is a 1000A standard class moulded case circuit breaker from the WS-V series, equipped with an electronic trip unit and rated for short-circuit interruption up to 85 kA at 400V. This performance level makes it ideal for main incoming distribution, large motor control centre incomers, and industrial power distribution panels where high prospective fault current is expected.
Key Specifications
| Parameter |
Value |
| Frame / Rated Current |
1000 A |
| Class |
NF-S - Standard |
| Rated Voltage (AC) |
Up to 690 VAC |
| Poles |
3-Pole (3P) and 4-Pole (4P) |
| Icu at 200 / 230 VAC |
125 kA |
| Icu at 380 / 400 / 415 / 440 VAC |
85 kA |
| Icu at 500 VAC |
65 kA |
| Icu at 690 VAC |
25 kA |
| Ics at 380 / 400 / 415 / 440 VAC |
43 kA (50.6% Icu) |
| Trip Unit |
Electronic (solid-state, adjustable) |
| Connection |
Front lugs or busbars |
| Dimensions (3P) |
210 mm * 406 mm * 190 mm |
| Weight (3P) |
23.5 kg |
| Electrical Life |
500 cycles at rated current |
| Mechanical Life |
3,000 cycles |
| Standard |
IEC 60947-2 / EN 60947-2 |
| IP Rating |
IP20 |
Electronic Trip Unit Advantages
The electronic trip unit provides adjustable overcurrent protection settings, allowing engineers to customize protection characteristics for selective coordination with downstream devices. This enables discriminative protection where faults on sub-circuits trip only the sub-circuit breaker, leaving the main distribution unaffected.
High Breaking Capacity Performance
With an 85 kA Icu rating at 400V, the NF1000-SEW can interrupt severe three-phase short-circuit faults and remain functional. The device provides substantial margin above typical industrial fault current ranges, ensuring reliable protection for main incoming applications.
Physical Installation
The NF1000-SEW features an IP20 protection rating and requires proper mechanical support in enclosed electrical switchgear cabinets. At 23.5 kg for the 3-pole unit, it is designed for fixed mounting with front terminal connections for busbars or cable lugs.
Frequently Asked Questions
Q1: What is the difference between the NF1000-SEW and a fixed thermal-magnetic MCCB at the same current rating?
The fundamental difference is the trip unit. The NF1000-SEW's electronic trip unit provides adjustable overcurrent protection settings for coordination with downstream devices, while fixed thermal-magnetic units have factory-determined trip curves that cannot be altered.
Q2: What is the difference between Icu 85 kA and Ics 43 kA at 400V?
Icu (ultimate breaking capacity) is the maximum fault current the breaker can interrupt without being destroyed. Ics (service breaking capacity) is the fault current level after which the breaker is rated for continued service without inspection. The NF1000-SEW can interrupt up to 85 kA but should be inspected after any fault above 43 kA.
Q3: Is the NF1000-SEW suitable for 690V systems?
Yes, the NF1000-SEW is rated for AC operation up to 690V. However, the breaking capacity at 690V reduces to 25 kA (Icu), so prospective fault current must be confirmed to be within this limit before specification.
Q4: What optional accessories are available for the NF1000-SEW?
Available accessories include shunt trip coils for remote electrical tripping, under-voltage releases, auxiliary contacts for remote status signalling, alarm contacts for fault indication, motor drive accessories, and rear terminal covers for busbar connections.
Q5: Can the electronic trip settings on the NF1000-SEW be changed in the field?
Yes, the electronic trip unit settings are adjustable in the field using the device's setting controls. Settings changes should be documented as part of the installation's protection coordination study and performed by qualified electrical engineers.
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