In Germany, the installation and use of balcony photovoltaic (PV) stations are becoming increasingly popular. The attention towards Residual Current Devices (RCDs) among residents is growing significantly, especially when considering the potential impact that balcony PV systems may have on existing home electrical safety systems. Let's delve into the systematic understanding of the relationship between these two devices.

Balcony PV systems refers to small-scale solar power stations that can be directly installed on the balconies of private residences.

They provide a handy and feasible way to generate green electricity for home use.

solar panels for apartment balcony

RCD is a safety device primarily used to detect and prevent electrical leakage accidents from happening, especially those that may lead to electrocution or fires. RCD can detect an imbalance in electrical current and swiftly cut off power supply once leakage is detected.

RCD working

Adding a whole Balcony PV system to your home, doesn’t increase the risk of RCD disconnection, Even if this is equivalent to adding a power source at the end of the line. In fact, if your PV system and energy storage are both correctly configured and installed in your home, that would be equivalent to adding a new household appliance and should not cause any electrical related issues.

The composition and working principle of balcony PV energy storage:

  • Balcony PV systems typically consist of the PV system itself, an energy storage section, and an inverter as key components. Specific equipment includes PV panels, inverters, DC controllers, and energy storage batteries.
  • In sunny areas at home like a balcony or terrace garden, PV panels are installed to maximize solar energy conversion to Direct Current (DC) electricity. The electricity generated by PV panels can be converted to Alternating Current (AC) through inverters for direct household use, or it can be stored in batteries via the DC controller for basic household needs when there is no sun at night.

The advantages of Balcony PV Energy Storage:

  • Balcony PV energy storage not only reduces the reliance on the public grid and lowers electricity expenditure but is also effective in reducing carbon emissions and combating climate change. The current power grid no longer pays for power provided by mini PVs to the grid. For balcony PVs, enhancing solar utilization is our main consideration.

Residual Current Device (RCD)

RCD is an essential safety device for homes. It is primarily used to detect and prevent electrical leakage accidents, especially those that may lead to electrocution or fires. RCDs can detect an imbalance in electrical current and swiftly cut off power supply once leakage is detected.

In essence, under normal conditions, the current between the line (live wire) and neutral wire should be equal. Any difference (residual current) between the two should be zero. However, when a circuit leakage occurs (such as electrocution on humans, or an internal short circuit in appliances), a part of the current would flow out via the ground wire or other channels.

 

RCD principle
Simple principle of RCD

This creates an inequality between the incoming circuit current (live wire current) and the returning current (neutral line current), forming residual current. RCD can detect this residual current, and if it exceeds the device's rated response current (usually 5-30mA), RCD will cut off the circuit within a short time (25-40 milliseconds) to prevent electrical leakage accidents. In electrical circuits, it serves as an important device to ensure human safety and prevent electrical fires. In the design of domestic circuits, it is advisable to install RCDs on each circuit for comprehensive home protection.

General causes for home RCDs disconnecting:

  • Appliance fault: If there's an issue with your electrical appliance, like a malfunction or damage, it might cause the RCD to trip.
  • Wire aging or damage: If the insulation layer of the wiring has ruptured or aged, it might lead to electric current leakage, thereby triggering the RCD.
  • Overload: If the current in the circuit exceeds the rated value of the RCD, it might cause the RCD to trip.
  • Humid environment: Humidity can lead to electrical leakage. For example, if the wires or electrical appliances operate in a wet environment, it may result in an RCD trip.
  • Electrical equipment suddenly turned on or off: Certain electrical appliances such as refrigerators, air conditioners, washing machines, etc., produce sudden current variations when turning on or off, which could cause the RCD to trip.
  • Testing button being pressed: The test button on RCD devices checks if the RCD is in good working order. If this button is pressed, it will also cause the RCD to disconnect.
  • Power cord mixed with wires: If the power cord comes into contact with the ground wire, it can also cause current leakage, thereby causing the RCD to disconnect.

How to assess and select Balcony PV components and other equipment compatible with RCD.

A direct and simple way is to confirm whether the balcony photovoltaic equipment purchased on has has passed IEC certification

For PV modules

  • IEC61215 Is a specification for the design and manufacture of crystalline silicon solar panels to ensure the reliability and safety for long-term open use.

  • IEC 61730 is the standard for PV component safety,including the testing and requirements for leakage current or any residual current that may cause harm to personnel and property.

PV standard

For inverters or DC controllers

  • IEC 62109 pertains to the specific safety requirements for inverters, including the detection and restriction requirements for residual operating current.

  • VDE-AR-N 4105 applies to PV inverters connected to the Low Voltage (LV) electrical grid. Includes the measurement and control requirements for residual current to ensure  to personnel and facilities safety.

The second method is to install the Balcony PV system correctly

  •      Professional evaluation and installation:

Install the equipment's wiring correctly according to the equipment's user manual.

  •      Grounding of PV systems:

Ensure the effective connection between the installed components, between the assembly and the bracket, and between the bracket and the earth

  •      The protective mechanism of a PV inverter:

Inverter is installed with two grounding methods that need to be effectively connected. The inverter contains the RCM, which is the residual current monitor. When the inverter leaks, immediately cut off the power or issue an alarm

  •      Current calculation and cable replacement:

the current calculation will be increased according to the capacity of the power station to be installed. For example, 600 / 800W, single-phase, the current is about 3-4A. You should calculate the current required by the whole home load, and increase the model of the home cable appropriately

If you have doubts, you may invite professional electricians to install. Correctly and safely installed balcony PV energy storage systems, like other household electric appliances, generally should not produce leakages.

The Importance of Maintenance and Inspection

The necessity of performing routine maintenance and inspections on the balcony PV system after installation is to ensure its long-term and safe operation. Like all household appliances, it is necessary to regularly check whether the equipment's exterior is damaged, whether the grounding connections are normal, whether the environment of the equipment is damp, and whether the wiring of the equipment is intact.

It is necessary to regularly check All the components of the balcony energy storage photovoltaic power station

  • whether the equipment's exterior is damaged
  • whether the grounding connections are normal
  •  whether the environment of the equipment is damp
  •  whether the wiring of the equipment is intact

In summary, Balcony PV power station provide  residents with an environmentally friendly and economically viable energy solution. At the same time, the Balcony energy storage PV system is equivalent to a small appliance in the household. They could satisfy the requirements for the safety of household property and personal safety of the product.

If you want to own your own balcony PV plant, then you can click here or picture to find the most suitable balcony PV system and micro battery for you.

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