Page 1: Detailed switchgear sizing. Component-level cable selection.
Molded Case Circuit Breakers are available in the following standard current ratings:
| Current Rating (A) | Breaking Capacity | Common Applications |
|---|---|---|
| 10, 16, 20, 25 | 10kA | Small commercial installations |
| 32, 40, 50, 63 | 15kA | Commercial and light industrial |
| 80, 100, 125 | 25kA | Industrial applications |
| 160, 200, 250 | 35kA | Heavy industrial applications |
| 320, 400, 500 | 50kA | Main distribution boards |
| 630, 800, 1000 | 65kA | Large industrial main feeders |
Miniature Circuit Breakers are available in the following standard current ratings:
| Current Rating (A) | Type | Common Applications |
|---|---|---|
| 6, 10 | Type B | Lighting circuits, general purpose outlets |
| 16, 20 | Type B, C | General purpose circuits, air conditioners |
| 25, 32 | Type C | Kitchen appliances, water heaters |
| 40, 50 | Type C, D | Industrial equipment, motors |
| 63 | Type D | Heavy machinery, transformers |
Motor Protection Circuit Breakers are available in the following standard current ratings:
| Current Rating (A) | Motor Power (kW) at 400V | Protection Features |
|---|---|---|
| 0.1 - 0.16 | 0.06 - 0.09 | Overload, short-circuit |
| 0.25 - 0.4 | 0.12 - 0.18 | Overload, short-circuit |
| 0.63 - 1.0 | 0.25 - 0.37 | Overload, short-circuit |
| 1.6 - 2.5 | 0.55 - 0.75 | Overload, short-circuit, phase failure |
| 4 - 6.3 | 1.1 - 1.5 | Overload, short-circuit, phase failure |
| 10 - 16 | 2.2 - 3.0 | Overload, short-circuit, phase failure |
| 20 - 25 | 4.0 - 5.5 | Overload, short-circuit, phase failure |
| 32 - 40 | 7.5 - 11 | Overload, short-circuit, phase failure |
| 50 - 63 | 15 - 18.5 | Overload, short-circuit, phase failure |
| 80 - 100 | 22 - 30 | Overload, short-circuit, phase failure |
Contactors are available in the following standard current ratings:
| Current Rating (A) | Coil Voltage | Common Applications |
|---|---|---|
| 9 - 12 | 24V, 110V, 230V | Small motors, lighting control |
| 18 - 25 | 24V, 110V, 230V, 400V | HVAC systems, small pumps |
| 32 - 40 | 24V, 110V, 230V, 400V | Industrial motors, compressors |
| 50 - 65 | 110V, 230V, 400V | Medium power motors, conveyors |
| 80 - 95 | 230V, 400V | Large motors, industrial machinery |
| 115 - 150 | 230V, 400V | Heavy machinery, large pumps |
| 185 - 225 | 400V, 525V | High power applications |
| 300 - 400 | 400V, 525V | Main power distribution |
| 500 - 600 | 400V, 525V | Large industrial applications |
Standard PVC insulated copper cables and their current carrying capacity (in air at 30°C):
| Cable Size (mm²) | Current Rating (A) | Max Power (kW) at 400V 3-phase | Typical Applications |
|---|---|---|---|
| 1.5 | 16 | 11 | Lighting circuits, small appliances |
| 2.5 | 21 | 14.5 | Socket outlets, lighting circuits |
| 4 | 28 | 19.5 | Cooker circuits, immersion heaters |
| 6 | 36 | 25 | Shower circuits, small motors |
| 10 | 46 | 32 | Small distribution circuits |
| 16 | 61 | 42 | Sub-main circuits, medium motors |
| 25 | 80 | 55 | Distribution boards, large motors |
| 35 | 99 | 68 | Main supply cables |
| 50 | 121 | 84 | Main supply cables |
| 70 | 155 | 107 | Heavy industrial applications |
| 95 | 188 | 130 | Heavy industrial applications |
| 120 | 218 | 151 | Large industrial installations |
| 150 | 250 | 173 | Large industrial installations |
| 185 | 285 | 197 | High power distribution |
| 240 | 340 | 235 | High power distribution |