What is a circuit breaker?
Circuit breakers interrupt the current of an overloaded electric circuit, ground fault, or short circuit when they sense an overload. As soon as a fault is detected, circuit breakers trip, shutting off current flow. In most cases, circuit breakers do not need to be replaced because they are not damaged.
TABLE OF CONTENTS
- What is a circuit breaker?
- 1. How to size a circuit breaker to protect the Rheonics SME?
- 2. Recommended circuit breakers
- 3. Sizing cable wire that goes from the circuit breaker to the power supply.
- 4. Resources
1. How to size a circuit breaker to protect the Rheonics SME?
It is important to select a circuit breaker for a device based on the maximum current it will draw. The Rheonics SME operates and draws a current of 120mA.
When selecting a circuit breaker for Rheonics SME, here are some recommendations:
Observe that with a 1A-rated current, this circuit breaker can sustain the 120mA current required by our electronics. The circuit breaker should also be capable of operating at the rated voltage of the power supply, our SME operates at 24V DC.
Figure 3. Rheonics SME wiring diagram.
2. Recommended circuit breakers
2.1. ABB S200
The S200 series is designed to protect installations from overloads and short circuits, ensuring reliability and safety under all operating conditions. Miniature circuit breakers (MCBs) are designed to be modular, meaning they can be easily snapped into standard DIN rail-mounted enclosures or distribution boards.
Figure 4. ABB Circuit Breaker M201-1A
2.2. Schneider Electric C60
The C60 series from Schneider Electric is designed for use in low-voltage electrical installations to protect circuits and electrical equipment from overcurrents and short circuits.
Figure 5. Schneider Electric circuit breaker M9F42201 
2.3. Eaton FAZ-B1/2
The Eaton FAZ-B1/2(Figure 1) is a miniature circuit breaker (MCB) designed for electrical distribution panels and enclosures to protect circuits and electrical equipment from overcurrents and short circuits.
3. Sizing cable wire that goes from the circuit breaker to the power supply.
Sizing wires appropriately for a wide range of applications can be a challenging and daunting task. Amperage serves as the gauge for the electrical current coursing through a circuit. The ampacity rating of a wire is what dictates the maximum safe amperage it can accommodate. To effectively determine the right wire size for your specific needs, it's crucial to have a grasp of wire ampacity ratings. Nevertheless, several external factors, including ambient temperature and conductor insulation, contribute to determining a wire's ampacity.
The calculation of wire ampacity is structured to ensure that it doesn't exceed a specified temperature increase under a given electrical load.
3.1. Power load of Rheonics SME
The general rule of thumb is that the cable size should be higher than the maximum load the circuit breaker can operate (This is to guarantee that the breaker will trip before the cable starts burning).
It is important to take into consideration the following aspects:
Based on our selection a 1A Circuit breaker can be used with cable caliber 16AWG or 18 AWG based on the table from below.
|12 AWG||20 Amps|
|14 AWG||15 Amps|
|16 AWG||13 Amps|
|18 AWG||10 Amps|
Table 1. ABYC Ampacity Rating Table at 30°C
EATON Circuit breaker - FAZ-B1/2