- C - trip curve type (response to a short circuit)
- 16 - rated current In, amps
| Marking | What it means |
|---|---|
C16 |
The main marking: the letter is the trip curve type (B, C, D), the number is the rated current In in amps. C16 reads as "type C, 16 amps". |
B C D |
The time-current curve type - the multiple of In at which the instantaneous (magnetic) release trips on a short circuit: B - 3–5·In, C - 5–10·In, D - 10–20·In. All types respond to overload identically. |
| 6000 | The number in a rectangle - the breaking capacity: the highest short-circuit current the breaker can interrupt without being destroyed. 6000 = 6 kA. Common values are 4500, 6000 and 10000 A. |
| 3 | The number in a square next to the breaking capacity - the energy limiting class (1, 2 or 3). Shows how quickly the breaker limits short-circuit energy; 3 is the best. |
230/400V ~ |
Rated voltage Un: 230 V per pole, 400 V between poles. The ~ symbol means alternating current. |
1P 2P 3P 1P+N |
Number of poles (switched conductors): 1P - live only, 1P+N - live and neutral, 3P - three phases, 4P - three phases and neutral. |
1 / 2 |
Numbers at the terminals. Odd (1, 3, 5) - supply side, usually on top; even (2, 4, 6) - load side, at the bottom. They help keep supply and load straight. |
I / O |
Lever position: I (or 1) - on, O (or 0) - off. On a tripped breaker the lever usually sits in the middle or lower position. |
In Ue Ui |
Rated current (In) and, less often, operating voltage (Ue) and insulation voltage (Ui) - on industrial breakers. |
IEC/EN 60898-1 |
The standard the breaker is built to. 60898 - residential modular breakers (curves B, C, D); 60947-2 - industrial (including A, K, Z). |
| Series, part no., brand | The series name, catalogue number and manufacturer - what you need to find an exact replacement. |
The letter and the number matter most
For household use the key
marking is C16: the
curve type and the rated current. The rated current In is the
current the breaker carries continuously without tripping; a sustained excess
triggers the thermal release (overload), and a short circuit triggers the magnetic
one. Pick the type for the kind of load, and the rating In for the cable size and
line current. For the actual trip currents, see the
breaker trip characteristics.
Breaking capacity
The number in the rectangle must be at least the prospective short-circuit current at the installation point. For apartment panels 4.5–6 kA is usually enough; near the service entrance and substation 10 kA units are used.
Important
Reference material; the markings are shown for typical modular breakers per IEC 60898. A specific manufacturer's marking may differ - check their documentation. Selection and installation should be done by a qualified electrician.