In an electrical network where multiple machines are powered simultaneously, it's crucial to be able to cut off power to each one individually, particularly for safety or maintenance reasons. For this purpose, a device called a disconnecting switch is used.
What is the purpose of a disconnecting switch?
A disconnecting switch is an electrical device that combines two essential functions. On one hand, it acts as a switch by allowing an electrical circuit to be opened or closed, meaning it can cut off or restore power to a machine. On the other hand, it functions as a disconnector, which means it can visibly and safely isolate part of the circuit, guaranteeing that no current is passing when the circuit is open. This dual functionality is particularly important for ensuring the safety of maintenance operations.
It's also important to note that not everyone working on an installation is necessarily an electrician. People without electrical training are generally not authorized to work directly on electrical panels, as this can be dangerous and requires specific skills.
However, non-electricians may need to perform maintenance on equipment requiring a power cut, such as a heat pump. This is why proximity cut-off devices like disconnecting switches are used. Disconnecting switches allow the power supply to an appliance to be cut off simply and safely, without needing to access electrical panels. This means a non-electrician can interrupt the power supply to a machine, switching it off for maintenance without risk of electrical accident.
What is the role of a fuse-holder disconnector?
The fuse-holder disconnector switch is an electrical protection device capable of isolating electrical circuits from the mains supply. The disconnector switch provides the lockout-tagout function, meaning the circuit is considered isolated once it is opened.
- The additional function of fuse protection is often added. This function protects the power supply line against overloads and short circuits.
- The additional switch function is also associated with it.
Please note that it's important to know that it is always operated when de-energized because it does not have an interrupt function.
Note: The main contacts ensure that the machine is isolated from the network, which is mandatory before any work is carried out.
How do I choose a disconnector?
Several steps are necessary to know how to choose a disconnector:
- Determine whether a disconnecting switch or a fuse holder disconnector is required.
- Determine the number of poles. These can be of different types:
> Single-pole + neutral
> Two-pole
> Three-pole
> Four-pole - Determine the operating voltage.
- Is the disconnector in a box?
- Determine the maximum current that the device can withstand for a limited time.
- Choose the accessories:
> The type of control: type of device used to operate the equipment (handle on the left, right on the front, offset, etc.)
> The fixing system: means of fixing the equipment
> The padlocking device
