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NDM2L-630
221.Applicable Scope and Purpose of Circuit BreakerThe NDM2L-630 molded case circuit breaker with the residual current protection (hereinafter referred to as circuit breaker) applies to infreque...
View detailsNDM2Z-250
1. Applicable Scope and Purpose of Circuit Breaker
The NDM2Z-250 DC molded case circuit breaker (hereinafter referred to as circuit breaker) applies to the DC system application environment and the electric circuit with the working voltage of DC250V and the working current of 250A. With the overload, short circuit and undervoltage protection functions, the circuit breaker can protect lines and power equipment from damage.
2. Specification and Model Description of CircuitBreaker
| ND M 2 Z – 250 □ / □ □ □ □ □ 1 2 3 4 5 6 7 8 9 10 11 | ||
| SN | SN name | NDM2Z |
| 1 | Enterprise code | ND: “Nader” low-voltage apparatus |
| 2 | Product code | M: Molded case circuit breaker (MCCB) |
| 3 | Design SN | 2 |
| 4 | Derived code of the series | Z: DC |
| 5 | Shell frame level | 250 |
| 6 | Operation mode | No code: Direct handle-operated mode |
| P: Motor-operated | ||
| Z: Rotation handle | ||
| 7 | Number of poles | 2, 3 |
| 8 | Release code | 0: Release (none) |
| 2: Instantaneous tripper only | ||
| 3: Complex tripper | ||
| 9 | Accessory code | See Table 1 |
| 10 | Rated current | See Table 2 |
| 11 | Cabling type | No code: Normal product |
| P: Connection busbar | ||
| Z1: Rear-plate connection | ||
| Z2Q: Plug-in front-plate connection | ||
| Z2H: Plug-in rear-plate connection | ||
3.Main Technical Parameters of Circuit Breaker
Table 2 Main Technical Parameters of Circuit Breaker
| Model | NDM2Z-250 | |||
| Rated current of frame Inm (A) | 250 | |||
| Rated current In (A) | 125, 140, 160, 180, 200, 225, 250 | |||
| Rated insulation voltage Ui (AC V) | 1000 | |||
| Rated impulse withstand voltage Uimp (V) | 8000 | |||
| Power frequency withstand voltage U (1min) (V) | 3500 | |||
| Utilization category | A | |||
| Rated working voltage Ue (DC V) | 250 | |||
| Number of poles | 2 | 3 | ||
| Rated limit short-circuit breaking capacity Icu (kA) | 35 | 35 | ||
| Rated operating short-circuit breaking capacity Ics (kA) | 35 | 35 | ||
| Operating performance (times) | Electrical life | 1500 | ||
| Mechanical life | Maintainable free life | 8500 | ||
| Maintainable life | 17000 | |||
3.1Selection of the circuit breaker connecting bus or cable cross-section area:
Table 3 Selection of the NDM2Z-250 Connecting Bus or Cable Cross-section Area
| Rated current (A) | 125, 140 | 160 | 180, 200, 225 | 250 |
| Wire cross-section area (mm²) | 50 | 70 | 95 | 120 |
3.2Tightening Torque of the Circuit Breaker Terminal and Mounting Screw
Table 4 Tightening Torque of the Circuit Breaker Terminal and Mounting Screw
| Model | Thread diameter (mm) | Torque (N·m) |
| NDM2Z-250 | M8 | 12 |
| M4 | 2.4 |
3.3Derating factor of temperature change for the circuit breaker
Table 5 Derating Factor Table of Temperature Change for the Circuit Breaker
| Model | Derating factor of product temperature change | |||||||
| NDM2Z-250 | Temperature (℃) | 40 | 45 | 50 | 55 | 60 | 65 | 70 |
| Derating factor | 1 | 0.982 | 0.963 | 0.944 | 0.924 | 0.904 | 0.882 | |
2) The above derating factors are measured at the frame current.
3.4High-altitude derating factor of the circuit breaker
Table 6 High-altitude Derating Factor Table of Circuit Breaker
| Elevation (m) | Working current correction coefficient | Power frequency withstand voltage correction coefficient | Isolation voltage correction coefficient |
| 2000 | 1 | 3500 | 1000 |
| 2500 | 1 | 3500 | 1000 |
| 3000 | 0.98 | 3150 | 900 |
| 3500 | 0.97 | 3000 | 850 |
| 4000 | 0.95 | 2800 | 810 |
| 4500 | 0.94 | 2650 | 770 |
| 5000 | 0.93 | 2500 | 730 |
1)The altitude of the installation site doesn’t exceed 2,500m. See the “High-altitude Derating Factor Table of Circuit Breaker” for the derating factor at the altitude;
2)The ambient temperature is -35℃ ~ + 70℃; the average within 24 h shall not be more
than +35℃. If the ambient temperature is higher than +40℃, the user needs to reduce the capacity. See the “Derating Factor Table of Temperature Change for the Circuit Breaker” for the derating factor;
3)Its relative humidity at an ambient temperature of +40℃ should not exceed 50%. A higher
relative humidity is allowed at a lower temperature. For example, the relative humidity at 20℃ can reach 90%; for frost due to temperature change, the corresponding measures should be taken;
4)The product can withstand the effects of wet air, salt mist, oil mist and mould;
5)The installation category of the circuit breaker connected to the main loop is: Category Ⅲ (power distribution and control level), The installation category of the circuit breaker not connected to the main loop is: Category Ⅱ (load level);
6)The pollution level is Level 3;
7)The product should be installed in places that are free from explosive media, media corrosive to metal, insulation damaging gas, and conductive dust, which should be also avoided from snow and rain;
8)In case of stricter user conditions than the above description, negotiate with the manufacturer.
5.Outline, Mounting Hole Dimensions and Safety Distance of Circuit Breaker
5.1Outline and mounting hole dimensions of circuit breaker
Note: The limit deviation not indicated with the tolerance dimensions is as per GB/T 1804-c.
5.2Safe mounting distance of circuit breaker
Table 7 Insulation Distance Mounted in the Metal Cabinet (Unit: mm)
| Mounting distance | A (inlet wire end to the cabinet face) | B (distance from side to the cabinet face) | C (outlet wire end to the cabinet face) | |
| Model | With a terminal cover | Without a terminal cover | ||
| NDM2Z-250 | 25 | 65 | 30 | 30 |
Table 8 Minimum Center Distance between Rowed Circuit Breakers (Unit: mm)
| Model | Width of circuit breaker | I Center distance | ||
| 2 poles | 3 poles | 2 poles | 3 poles | |
| NDM2Z-250 | 107 | 107 | 137 | 137 |
Table 9 Minimum Center Distance between Stacked Circuit Breakers ( Unit: mm)
| Model | H (distance of circuit breaker from bottom) | |
| With a terminal cover | Without a terminal cover | |
| NDM2Z-250 | 90 | 93 |
2)Cable insulating connection
3)Connection without insulation
Requirements: Check whether the terminal cover or phase partition is assembled properly before products are energized.
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