ATS photovoltaic switch: what it is and how it works

When it comes to solar energy, the focus almost always falls on the most visible and iconic components: the photovoltaic panels placed on the roof or the modern design of a latest-generation inverter. However, the real efficiency of a plant and its ability to protect the home from electrical grid disruptions depend on components often installed inside electrical panels, less known to the general public but essential for safety and business continuity. One of these is undoubtedly the ATS switch for photovoltaic.

The acronym ATS stands for Automatic Transfer Switch, which can be translated into Italian as an automatic transfer switch. It is a smart device that acts as a 'director' of home energy distribution. In a world where dependence on electricity is total, both for work and for home comfort, having a system that autonomously manages energy sources is no longer a luxury, but a technical necessity for those who aim at self-consumption.

In this guide, we will explore in detail how this technology works, why it has become a pillar of battery systems and what are the considerations to make before installing one in your home.

What is an ATS switch and why is it essential for photovoltaic

To understand the importance of an ATS switch, we must imagine the electrical system of a modern home as a complex ecosystem where different energy sources coexist: the national grid (Enel or other distributors), the photovoltaic system and, increasingly, a battery storage system or an emergency generator.

The ATS switch is an electromechanical or static device that has the task of selecting, in fractions of a second, which of these sources should power household loads (lights, appliances, computers). Its main function is to ensure that the house is never left in the dark, even in the event of public line failures or sudden power drops.

A smart supervisor for your energy

Unlike a manual switch, which would require human intervention to move the lever in the event of a blackout, the ATS operates in total autonomy. It constantly monitors the electrical parameters (voltage and frequency) of the primary source. If these parameters go out of the safe range or if the power fails completely, the ATS “disconnects” the faulty line and instantly “attacks” the backup source.

This process is so fast that, in most cases, the inhabitants of the house do not even notice the passage. The digital clocks in the ovens do not reset and the computers do not turn off, thus protecting not only the comfort but also the integrity of the most sensitive electronic devices.

How the Automatic Transfer Switch technically works: the switching phases

The operation of an ATS can be divided into three critical phases that occur in a cyclical and uninterrupted manner. The precision of these phases determines the quality of the device and the safety of the entire photovoltaic system.

1. Continuous monitoring of sources

The ATS is 'always awake. ' Internal sensors analyze the input voltage from the main electrical network. As long as the grid is stable and provides power within pre-established limits, the ATS keeps the contact closed on the primary source. In this phase, the photovoltaic system works normally, powering the house and charging the batteries, while the network acts as a support or receiver for excess energy.

2. Failure or deficiency detection

When an anomaly occurs (a blackout, an excessive voltage drop or a fault on the external line), the ATS detects the change in milliseconds. This is the most delicate phase: the device must be sensitive enough to intervene immediately, but not so sensitive as to activate itself for small irrelevant changes that would not jeopardize the appliances.

3. Safe switching (Switching)

Once the absence of energy from the primary source has been ascertained, the ATS opens the network circuit and the backup source comes into play. If the system is equipped with batteries, the ATS instructs the system to draw energy from the storage. It is essential that the two sources are never improperly connected at the same time to avoid the phenomenon of “backfeeding” (return of current to the external network), which could be dangerous for technicians who work on cables in the street.

The advantages of integrating ATS and storage systems

If a traditional photovoltaic system without batteries goes out during a blackout (for regulatory safety reasons), a system equipped with an ATS storage and switch transforms the house into a sort of “energy island”. This scenario offers advantages that go far beyond simple economic savings.

Business continuity and critical load protection

In an era of extreme smart working, a power interruption of a few minutes can cause the loss of working hours or the interruption of important video conferences. The ATS ensures that the internet connection and home servers remain active. In addition, for those who live in isolated areas where blackouts are frequent due to bad weather, ATS ensures that critical systems such as refrigerators, freezers and heat pumps continue to work, avoiding food damage or thermal discomfort.

Optimized management of self-consumption

The ATS works in synergy with the inverter to maximize the use of the energy produced by the panels. During the day, if solar production exceeds consumption, ATS allows the system to give priority to domestic charging and battery charging. If suddenly a cloud obscures the sun and the batteries are empty, the ATS manages the transition to the grid in a fluid way, avoiding electrical stress on the plant components.

Plant safety and risk reduction

A good ATS switch includes protections against short circuits and overloads. Acting like a controlled gate, it prevents external grid anomalies from spreading inside the photovoltaic system, safeguarding the house's most expensive investment: the inverter and the battery pack.

Selection guide: technical parameters and purchase criteria

Not all ATS switches are the same. The choice of the correct model depends on the specific characteristics of the house and the installed solar system. Here are the main factors to consider before buying.

Amperage and nominal power

The ATS must be properly sized to withstand the house's maximum load. If the supply contract is 3 kW, 6 kW or higher, the switch must have a current capacity (expressed in Amperes) sufficient to manage all the appliances turned on at the same time without overheating. An error in sizing can lead to contact fusion or to untimely thermal protection jerks.

Transfer Time

This is the fact that distinguishes a cheap product from a professional one. The fastest ATS have transfer times of less than 10-20 milliseconds. This speed is critical if you have sensitive electronic devices at home. If the switch time is too long, the computers will restart despite the presence of batteries.

Number of poles and configuration

Depending on whether the domestic system is single-phase or three-phase, the ATS must have 2 or 4 poles respectively. It is essential that the switch interrupts both the phase and the neutral to ensure maximum safety during maintenance operations and to avoid unwanted ground returns.

Installation and regulatory considerations

The installation of an ATS switch is not an operation that can be done with 'do it yourself'. It is a matter of intervening on the beating heart of the electrical system, where high currents pass and where safety must be absolute.

Positioning and wiring

Usually, the ATS is installed on a DIN rail inside the general electrical panel or in a dedicated panel immediately downstream of the meter and the inverter. The specialized technician must ensure that the wiring is of adequate cross-section and that the necessary magnetothermic and differential protections are present.

Periodic maintenance

Although they are devices designed to last for years, mechanical ATS switches have moving parts (contactors or motors) that can wear out over time. It is good practice, during the annual review of the photovoltaic system, to have the technician check the condition of the ATS contacts to ensure that there are no signs of oxidation or electric arcs that could compromise the speed of response.

The technical barriers of domestic photovoltaic

Installing a system complete with panels, batteries, inverters and advanced systems such as ATS requires meticulous planning, adequate space and a significant economic investment. In addition to the cost of the components, it is necessary to consider the costs of professional installation, the paperwork for connecting to the network and the continuous need for maintenance to maintain efficiency at the highest levels.

Many B2C users are discouraged by the technical complexity of managing a 'micro-electrical system' in their own home, even as a simple plug and play system,. The management of components such as ATS, however useful, adds an additional level of complexity that not everyone is ready to face, especially if they live in condominium settings or in areas with architectural constraints where the installation of physical hardware is limited or prohibited.

The alternative of shared solar parks: efficiency without complexity

For those who want the benefits of photovoltaic (economic savings, clean energy and protection from price increases) without having to manage the technical complexity of inverters, batteries and ATS switches, there is today an innovative and simplified solution: participation in shared solar parks.

Choose the shared solar parks as an alternative to traditional photovoltaic, it allows you to overcome any technical barrier. In this model, you don't need to install any physical devices in your home. You won't have to worry about component maintenance, the switching time of an ATS, or battery degradation over time.

How does the GridShare solution work

Through companies such as GridShare, it is possible to acquire shares of large photovoltaic plants located in geographical areas with excellent solar radiation, managed by professionals. The energy produced by these plants is fed into the grid and the value generated translates into a direct economic benefit for the participant, which can be used to reduce the costs of their energy bill.

This turnkey solution offers several strategic advantages:

• Zero maintenance: You don't have to worry about technical failures or replacement of worn components.
• Maximum efficiency: Industrial plants use much more advanced monitoring and management technologies than domestic ones.
• Total flexibility: You can participate in the production of green energy even if you live in your own homeless apartment or in a shady area.

In conclusion, although devices such as the ATS switch are excellent for those who choose the path of physical energy independence, the transition to shared solar represents today the simplest, most democratic and efficient way to contribute to the green revolution and protect their savings without technical complications.