A circuit breaker gauge is the rated current capacity (in amperes) that indicates how much electrical current the breaker is able to handle without tripping. It must be proportionate to the cable size (cross-sectional area) to ensure adequate protection and avoid overheating or fire concerns.
The minimum cross-section of the conductor is the smallest wire size (mm²) that may safely carry the circuit breaker’s rated current. It is determined by several parameters, including current rating, insulation type, ambient temperature & installation conditions.
Always choose a cable size based on the breaker rating & load current as the breaker protects the wire & the wire must be able to safely carry the breaker’s rated current.
| Breaker Rating (A) | Minimum Copper Cable Size (mm²) | Remarks |
|---|---|---|
| 6 A – 10 A | 1.0 mm² | Lighting circuits |
| 16 A | 1.5 mm² | Light or small load outlets |
| 20 A – 25 A | 2.5 mm² | Socket circuits |
| 32 A – 40 A | 4.0 mm² | Air conditioners, heavy loads |
| 50 A – 63 A | 6.0 mm² | Sub-main or distribution circuits |
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