General rules for choosing MCB.
Technical data of the network at the point considered:
The earthing systems, short-circuit current at the circuit breaker installation point. which must always be less than the breaking capacity of this device, network normal voltage.
There are 3 curve characteristics for magnetic operation:
B curve (3-5In) protection and control of the circuits against length cables in TN and IT SYSTEMS.
C curve (5-10In) protection and control of the circuits against overloads and short-circuits; protection for resistive and inductive loads with low inrush current.
D curve (10-20In) protection and control of the circuits against overloads short-circuits; protection for circuits which supply loads with high inrush current at the circuit closing (LV/LV transformers, breakdown lamps).
Specifications
Each pole of the circuit breaker power consumption
| ElectricalFeatures | Standard |
| IEC/EN 60898-1 |
| Rated current In | A | 1,2,4,6,10,16,20,25,32,40,50,63 |
| Poles | P | 1,2,3,4 |
| Rated voltage Ue | V | AC 240/415 |
| Insulation voltage Ui | V | 500 |
| Rated frequency | Hz | 50/60 |
| Rated breaking capacity | A | 3000,4500(2~40A/6000) |
| Rated impulse with stand voltage(1.2/50) Uimp | V | 4000 |
| Dielectric test voltage at ind. Frqu, for 1 min | KV | 2 |
| Pollution degree |
| 2 |
| Thermo-magnetic release characteristic |
| B,C,D |
| Electrical life | T | 4000 |
| Mechanical life | T | 10000 |
| Protection degree |
| IP20 |
| Reference temperature for | ℃ | 30 |
| Setting of thermal element |
|
|
| Ambient temperature(with daily average ≤35℃) | ℃ | -5~+40(Special application please refer to temperature compensation correction) |
| Storage temperature | ℃ | -25~+70 |
| Installation | Terminal connection type |
| Cable/Pin type busbar/U type busbar |
| Terminal size top/bottom for cable | mm2 | 25 |
| AWG | 18-3 |
| Terminal size top/bottom for busbar | mm2 | 25 |
| AWG | 18-3 |
| N*m | 2 |
| In-Ibs. | 18 |
| Mounting |
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| Connection |
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Temperature derating
Please refer to table below for temperature compensation correction
| RatedCurrent In(A) | Temperature compensation coefficient under various operating temperature |
-10℃ | 0℃ | 10℃ | 20℃ | 30℃ | 40℃ | 50℃ | 55℃ | 60℃ |
| 1-6 | 1.20 | 1.14 | 1.09 | 1.05 | 1.00 | 0.96 | 0.80 | 0.75 | 0.70 |
| 10-32 | 1.18 | 1.12 | 1.08 | 1.04 | 1.00 | 0.96 | 0.92 | 0.88 | 0.84 |
| 40-60 | 1.16 | 1.12 | 1.07 | 1.03 | 1.00 | 0.97 | 0.87 | 0.83 | 0.80 |
