B and C circuit breaker characteristics and their impact on LED lighting
The characteristics of B and C type circuit breakers define, among other parameters, the operating range of the magnetic trip mechanism. In standard miniature circuit breakers (MCBs), a Type B breaker typically trips at 3 to 5 times its rated current, while a Type C breaker trips at 5 to 10 times its rated current.
For a B16 breaker, this corresponds to approximately 48-80 A, while a C16 breaker typically operates within the 80-160 A range. As a result, a Type C breaker can generally tolerate higher short-duration current peaks. However, it is not always the correct solution. Factors such as fault loop impedance, cable current-carrying capacity, and electrical safety requirements must also be verified. Circuit breaker selection should therefore be evaluated within the context of the entire installation.
Maximum number of LED drivers on B16 and C16 breakers
There is no universal number of luminaires that can be connected to a B16 or C16 circuit breaker, as the result depends on the characteristics of the LED drivers and the specification of the protective device being used. Any calculation of the maximum number of LED drivers per breaker should be based on the manufacturer's technical documentation.
| Parameter |
B16 |
C16 |
| Rated current |
16 A |
16 A |
| Typical magnetic trip range |
48–80 A |
80–160 A |
| Maximum number of LED drivers |
Depends on luminaire specifications |
Depends on luminaire specifications |
These operating ranges do not directly determine the permissible number of drivers connected to the circuit. To establish that value, the inrush current magnitude, pulse duration, and luminaire manufacturer's recommendations must be assessed. The proposed solution should then be verified against applicable electrical safety requirements.
Group switching vs sequential switching of LED luminaires
The method used to switch lighting on has a significant effect on the instantaneous load of the circuit. During group switching, multiple LED drivers draw inrush current at almost exactly the same moment, potentially causing a circuit breaker to trip.
Sequential switching involves energizing individual lighting groups with a controlled time delay between them, reducing the accumulation of inrush current peaks.
This approach can be particularly beneficial in warehouses, industrial halls, and large office environments where many luminaires are installed. Dividing the lighting system into zones makes it easier to control startup behavior and adapt operation to the needs of the facility.
Inrush current limiters
If luminaire specifications indicate a risk of nuisance tripping, the use of inrush current limiters may be considered. These devices are designed to reduce the current peak that occurs when power is applied.
The correct solution should be selected based on the number of connected drivers, the load characteristics, and the expected switching frequency.
It is important to note that inrush current limiters do not replace proper circuit protection design or fault-current verification. Before installation, compatibility with the selected LED drivers and compliance with manufacturer recommendations should always be confirmed.
The impact of cable length and conductor size
Cable length and conductor cross-section influence voltage drop, circuit impedance, and the effectiveness of electrical protection measures. Longer cable runs increase circuit impedance, which is why lighting designers must consider route length, conductor size, installation method, and permissible cable loading.
These parameters should also be verified against fault conditions and the required automatic disconnection times. The protective device must be suitable not only for the connected load but also for the actual operating conditions of the installation.
Why do breakers trip after replacing fluorescent lighting with LEDs, even when power consumption is lower?
Lower power consumption during normal operation does not automatically mean lower electrical stress during startup. One common reason circuit breakers trip after fluorescent luminaires are replaced with LED fittings is the high inrush current generated by LED drivers, especially when many luminaires are energized simultaneously. The type of protective device and the characteristics of the existing electrical installation can also contribute to the issue.
In such cases, the technical documentation of the new luminaires should be reviewed and their electrical characteristics checked against the installed protection devices. Depending on the results, solutions may include splitting the circuit into smaller sections, implementing sequential switching, or reducing the inrush current.
How should an LED lighting circuit be designed?
The number of luminaires connected to a single circuit breaker should always be determined on the basis of LED driver specifications, technical documentation, and the conditions of the installation. A proper assessment includes inrush current, circuit breaker characteristics, conductor size, and the effectiveness of electrical protection measures.
At Lena Lighting, we provide comprehensive technical documentation for our luminaires, helping electrical contractors, designers, and installers account for critical parameters during the planning stage. However, the final selection of protective devices and the number of luminaires connected to a circuit should always be based on the specific requirements and operating conditions of the installation.