Schneider NT06H2 Air Circuit Breaker

NT: MasterPact NT series air circuit breaker (ACB, legacy model, discontinued; replacement model MTZ1 06H2)

06: Frame size 06, frame rated current 630A

H2: Breaking capacity class H2; Icu=50kA@440VAC, short-time withstand current Icw=50kA (1s), Class B selective protection

Core Electrical Parameters

Key Notes

1. Discontinuation Status: NT series scheduled for end-of-sale by the end of 2025. Replacement model MTZ1 06H2, part number LV947203 (draw-out version)
2. Parameter Clarification

Ue=690V: Maximum normal operating voltage

Ui=1000V: Power frequency withstand voltage

Uimp=12kV: Lightning impulse withstand voltage. NOT applicable for 12kV high-voltage switchgear, this is an insulation index for low-voltage ACB

3. Application: Incoming feeder, bus tie and heavy-load outgoing feeder in low-voltage distribution systems, for industrial plants, data centers and marine power distribution; supports selective protection and coordination with upstream/downstream devices
4. Reference Frame Part Numbers

NT06H2 3P Fixed: 47113

NT06H2 3P Draw-out: 47203

NT06H2 4P Fixed: 47119

Accessories & Spare Parts

Trip Units: MicroLogic 2.0 / 5.0 / 6.0 / 7.0 (overload, short-time delay, instantaneous and earth-fault protection)

Accessories: Motor operating mechanism, auxiliary contacts, fault alarm contacts, closing coil, shunt trip coil, door interlock, phase barriers

Draw-out base: Mandatory independent cradle for draw-out version

Troubleshooting Guidelines

1. Failure to close: Undervoltage coil de-energized, incomplete spring charging, cradle not in connected position, interlock blocking
2. Unintended tripping: Check trip unit protection curve, earth fault, harmonic distortion and temperature rise
3. Insulation test: Power frequency withstand test at Ui=1000V level; 12kV impulse withstand is type-test only, no on-site 12kV impulse test

Domestic Alternative Reference

Domestic MT06H2 (Schneider domestic MT series). Compatible breaking capacity and mounting dimensions for direct replacement.

Schneider MasterPact NT06H2 Air Circuit Breaker Technical Manual (Full Engineering Version, per original datasheet 0613CT0001)

Remarks: NT series is legacy discontinued ACB, frame size NT06, In=630A; breaking class H2; frame supplied without trip unit, MicroLogic trip unit to be ordered separately; standard IEC 60947-2, isolating function, Class B selective protection

Table of Contents

1. Product Overview & Model Code Explanation
2. Rated Electrical Parameters
3. Mechanical Parameters, Overall Dimensions & Weight
4. MicroLogic Trip Unit Selection
5. Accessory List & Secondary Terminal Definition
6. Installation & Wiring Requirements
7. Operation, Handling & Interlock Description
8. Maintenance, Inspection & Troubleshooting
9. Ambient Conditions
10. Replacement Model Information
11. Original Document Index
12. Product Overview & Model Code Explanation

1.1 Overview

MasterPact NT series low-voltage air circuit breakers for incoming feeders, bus ties and high-current outgoing feeders in 400/690V low-voltage distribution systems. NT06H2 maximum frame rating 630A, available in draw-out or fixed construction, spring charged operation, configurable with intelligent MicroLogic protection unit, supports remote signalling, metering and communication.

Important Reminder: Ui=1000V (rated insulation voltage), Uimp=12kV (lightning impulse withstand voltage). NOT 12kV high voltage circuit breaker, only for AC ≤690V low-voltage distribution.

1.2 Model Breakdown

NT: MasterPact NT series air circuit breaker

06: Frame size 06, frame rated current 630A

H2: Breaking class H2; Icu=50kA@440VAC, Icw=50kA 1s, Class B selective

Part Numbers:

NT06H2 3P Fixed: 47113

NT06H2 3P Draw-out: 47203

NT06H2 4P Fixed: 47119

1.3 Product Status

NT series scheduled end-of-sale by end of 2025; replacement model MTZ1 06H2, part number LV947203 (draw-out). Mounting dimensions and secondary interfaces fully compatible for direct replacement.

2. Rated Electrical Parameters

3. Mechanical Parameters, Overall Dimensions & Weight

3.1 Mechanical Endurance

Mechanical life: 20,000 operations (no-load make/break)

Electrical life (400V, In): 10,000 operations

Spring charging: Manual charging / motor charging MCH optional

3.2 Overall Dimensions (3P, unit: mm)

Fixed type: W300 × H415 × D266

Draw-out type (with cradle): W300 × H415 × D376

4P version width 360mm, height and depth unchanged

3.3 Weight

Fixed frame only: ≈32kg

Draw-out frame + cradle: ≈52kg

3.4 Three positions for draw-out version

1. Connected Position: Main circuit and secondary circuit fully connected, normal operation
2. Test Position: Main circuit disconnected, secondary circuit remains connected for protection test
3. Disconnected Position: Main and secondary circuits fully disconnected, breaker can be withdrawn for maintenance
4. MicroLogic Trip Unit Selection (Must be ordered separately, not included with frame)

Protection setting range: Ir (long-time) 0.4~1×In; Isd short-time delay 0.5~10×In, delay 0.1/0.2/0.4s; Ii instantaneous 1~15×In.

5. Accessory List & Secondary Terminal Definition

5.1 Optional Accessories

1. MCH: Charging motor AC220V / DC24V
2. XF: Closing solenoid AC220V / DC24V
3. MX: Shunt trip coil (remote opening)
4. MN: Undervoltage release (MNu time-delayed undervoltage for auto-transfer application)
5. OF: Auxiliary contacts (CB on/off status feedback)
6. SDE: Fault trip contacts (signal for overload/short-circuit/earth fault trip)
7. PF: Cradle position contacts (connected / test / disconnected position)
8. Phase barriers, cabinet door interlock, mechanical interlock cables, padlock device
9. ULP communication module: Modbus-RTU, remote signalling & metering

5.2 Secondary Terminal Definition

6. Installation & Wiring Requirements
7. Mounting: Vertical upright installation, ±5° tilt allowed; inverted mounting prohibited
8. Main circuit connection: Front connection / rear horizontal / rear vertical connection; apply specified tightening torque for copper busbars to avoid overheating
9. Secondary control wiring: 0.75~1.5mm² multi-core shielded cable; independent AC220V/DC24V control power supply for secondary circuit
10. Insulation test: Power frequency withstand test at Ui=1000V level; 12kV impulse withstand is type test only, no on-site 12kV impulse test
11. Draw-out operation: Use dedicated crank for rack-in / rack-out; prohibit racking out breaker from connected position under live condition
12. Operation, Handling & Interlock Description

7.1 Operation Procedure

1. Charging: Manual charging handle or MCH motor auto charging; charging complete, charged indicator lights on
2. Closing: Local front panel close pushbutton / XF remote close; verify interlock conditions before closing
3. Opening: Local open pushbutton / MX remote opening / automatic protection tripping; after fault trip, fault reset button must be manually reset before re-closing

7.2 Interlock (Two-incoming one bus tie scheme)

Mechanical interlock: Steel cable mechanical interlock, physically prevents simultaneous closing of three ACBs

Electrical interlock: Close circuit wired in series with normally closed contacts of other breakers for double protection

Cradle position interlock: Closing circuit blocked when not in connected position, closing prohibited

Fault trip interlock: Auto-transfer closing logic blocked upon SDE contact activation

8. Maintenance, Inspection & Troubleshooting

8.1 Periodic Maintenance

Semi-annual: Check charging status, on/off indication, contact temperature rise, tightness of secondary wiring

Annual: Dust cleaning, insulation inspection, trip unit test (using MicroLogic test cable)

Overhaul (every 5 years): Disassemble to inspect main contacts and arc chamber, mechanical lubrication, mechanical life verification

8.2 Typical Troubleshooting

1. Failure to close

Incomplete charging; undervoltage MN coil de-energized; cradle not in connected position; interlock blocked; fault trip not reset

2. Unintended tripping

Verify protection curve; earth fault; harmonic overload; loose wiring with overheating; voltage dip triggering MN undervoltage trip

3. Charging failure

No power supply to MCH motor; jammed charging mechanism; damaged charged-ready contact

4. No fault signal output

Wrong SDE auxiliary contact wiring, burnt contacts

9. Ambient Conditions

Operating ambient temperature: -5℃ ~ +70℃; derating required above 40℃

Storage temperature: -40℃ ~ +85℃

Relative humidity: ≤95% (non-condensing)

Altitude: ≤2000m; derating and insulation correction required above 2000m

Degree of protection: Device IP30; IP40 with cabinet door closed

Pollution degree: 3

10. Replacement Model Information

NT06H2 → MTZ1 06H2

Frame 630A, Icu=50kA, compatible MicroLogic trip unit

Mounting dimensions, primary busbar and secondary terminals fully compatible, no cabinet modification required for in-panel retrofit

Supports ECOSTRUXURE Power software commissioning, upgraded communication interface

Schneider MasterPact NT Full Series Model List (IEC Version, Discontinued ACB, Frame 630~1600A)

Naming Rule: NT + Frame Code + Breaking Class

Frame Code: 06=630A; 08=800A; 10=1000A; 12=1250A; 16=1600A

Breaking Class: N1 / H1 / H2 / L1; Construction: Fixed / Draw-out; Poles 3P/4P; Frame without trip unit, MicroLogic to be ordered separately

Common Base Parameters: Ui=1000V, Uimp=12kV, Ue max AC690V, Class B selective protection

Breaking Class Definition (440V, Icu ultimate breaking capacity)

N1: 35kA

H1: 42kA

H2: 50kA (same class as NT06H2)

L1: 130kA (current-limiting type, application for high short-circuit capacity)

NT Full Model List

Draw-out part number: add 10 to the last digit. Example NT06H2 3P Draw-out:47203; 4P fixed part number +6 (NT06H2 4P Fixed 47119)

Derivative Isolator Models (HA version)

NTxxHA: Isolator (without trip unit, IEC60947-3)

NT06HA / NT08HA / NT10HA / NT12HA / NT16HA

Compatible Trip Unit List (Universal for full NT series)

MicroLogic 2.0: Long-time overload only

MicroLogic 5.0A: Long-time + short-time delay + instantaneous (preferred for incoming / bus tie)

MicroLogic 6.0A: 5.0A + earth fault protection

MicroLogic 7.0A: 6.0A + residual current protection + harmonic measurement

Replacement Cross Reference Table (NT → MTZ1)

Selection Remarks

1. NT series fully discontinued, not recommended for new projects; MTZ1 can be used for spare parts replacement for existing projects with compatible primary and secondary interfaces.
2. L1 current-limiting type for systems with extremely high short-circuit current, higher cost; H2 is preferred for normal incoming feeder and bus tie.
3. Rated current can be derated within the same frame by changing current sensor inserts, e.g. NT06 frame available with 400A/500A/630A sensors.