Circuit-breaker
From Electrical Installation Guide
The circuit-breaker/disconnector fulfills all of the basic switchgear functions, while, by means of accessories, numerous other possibilities exist
As shown in Figure H20 the circuit-breaker/ disconnector is the only item of switchgear capable of simultaneously satisfying all the basic functions necessary in an electrical installation.
Moreover, it can, by means of auxiliary units, provide a wide range of other functions, for example: indication (on-off - tripped on fault); undervoltage tripping; remote control… etc. These features make a circuit-breaker/ disconnector the basic unit of switchgear for any electrical installation.
| Functions | Possible Conditions | ||
|---|---|---|---|
| Isolation | ☑ | ||
| Control | Functional | ☑ | |
| Emergency switching | ☐ | (With the possibility of a tripping coil for remote control) | |
| Switching-off for mechanical maintenance | ☑ | ||
| Protection | Overload | ☑ | |
| Short-circuit | ☑ | ||
| Insulation fault | ☐ | (With differential-current relay) | |
| Undervoltage | ☐ | (With undervoltage-trip coil) | |
| Remote control | ☐ | Added or incorporated | |
| Indication and measurement | ☐ | (Generally optional with an electronic tripping device) | |
Fig. H20 – Functions performed by a circuit-breaker/disconnector
