Plug in solar – the balcony solar system.

Plug-in solar, also known as balcony solar, is becoming increasingly popular in many countries around the world. Here are some examples:

• Europe: Austria, Belgium, Czech Republic, Denmark, France, Netherlands, Norway, Sweden, and Switzerland all have regulations in place that allow for balcony solar installations .
• Other regions: China and Italy are also seeing a rise in balcony solar use.
  England Lags behind as usual. but lets look into this..

Balcony solar, also known as plug-in solar, is a growing trend in Germany. The exact figures are hard to get a handle on, however. The latest data from the market master data register at Germany’s Federal Network Agency indicates that the country has almost 400,000 PV systems with up to four modules, the majority of which are likely to be plug-in solar devices.
These small solar systems are ideal for renters and people who don’t have roof space for traditional solar panels. They are easy to install and can generate enough electricity to power some of your appliances or offset your electricity use. However the “Masses” go ahead with a range of “micro solar” and a leading “person” “estimates that there were actually around 1.5 million devices connected to the grid in Germany in summer 2023″ yes that’s around 3 times that of the “legal installations”.

Here’s a quick rundown of what you need to know about balcony solar in Germany:

• ** legality:** In Germany, balcony solar systems are generally permitted, as long as no monument protection or building regulations are violated.
• Size limit: The current limit for balcony solar systems in Germany is 600 watts (As of April 1st 2024 800w).
• Registration: You must register your balcony solar system with your local grid operator (as of April 2024 you register with WDM).
• Meters: There are some exceptions with older meters. Systems cannot be used with Ferraris meters that can run backwards. The grid operator must replace these meters before the solar system can be put into operation. There is a grace period for this regulation.

A Single German standard specifically for plug-in solar devices is not yet finalised, but there are key points to consider for safety and regulations:

• Draft Standard: The German Commission for Electrical, Electronics and Information Technologies (DKE) is developing a product standard specifically for plug-in solar equipment [VDE dialog]. This standard is still under development but aims to ensure the safety of users and installations.
• Existing Standard for Installation: DIN VDE V 0100-551-1 applies to installations. This standard for low-voltage electrical installations emphasizes that plug-in solar shouldn’t be treated like household appliances due to its power generation aspect [VDE dialog].
• Plug Concerns: Standards bodies like DKE recommend a special plug-and-socket system different from the standard Schuko plug typically used in Germany. This would prevent accidental contact with live parts and ensure a safer connection [VDE press release].

Overall, safety with plug-in solar in Germany focuses on preventing electrical shock and ensuring proper grid integration. While a single product standard awaits finalization, existing installation regulations and the proposed dedicated plug system aim to address these safety concerns.
Here’s a breakdown of the key points regarding VDE V 0100-551-1 and its connection to plug-in solar:

• Focus on Safe Power Injection: The standard emphasizes following existing regulations for low-voltage electrical installations when connecting plug-in solar devices. This is because these systems generate power, unlike typical appliances that only consume electricity.
• Existing Standards Apply: VDE V 0100-551-1 doesn’t create entirely new regulations. Instead, it highlights the importance of following existing safety guidelines for low-voltage installations when dealing with plug-in solar.
• Potential Grid Issues: A critical aspect addressed by the standard is the potential for issues arising when connecting plug-in solar devices to the grid. To minimize these risks, standards bodies recommend using a dedicated plug-and-socket system specifically designed for this purpose. This would help prevent accidental connection problems.

buy Deye 800W micro inverter at our shop

Plug in Solar in the UK.

Plug in Solar in the UK is NOT legal, however there are two grey areas, the feed is before the load (new circuit) which the DIY’er cannot do. and the second is a rather more complex route, Plug in Solar.co.uk use a “fused spur” approach which allows DIY installation.

Why is this a problem? if they do it abroad why not here?
Good question, but its actually down to stupidity and knee gerk government with bad English and conceptions. Like asking road tarmac’ers for guidance on brain surgery..
before health and safety went bonkers, and with stupid is and stupid does, there was a whole array of electrical fires.

The Great British Plug

The BS 1363 system of plugs and sockets, as enforced by the Plugs and Sockets etc. (Safety) Regulations 1994, has ensured that the UK has a level of domestic electrical mains connector safety unparalleled elsewhere. BS 1363 Plugs and Sockets – Regulation

The system of UK domestic plugs and sockets to British Standard 1363 is generally agreed to be the safest in the world, it was designed in the 1940s to be inherently child-safe, a feature which other countries have started to introduce only recently. Statutory Instrument 1994 No. 1768, The Plugs and Sockets etc. (Safety) Regulations 1994, requires standard plugs to comply with BS 1363, however it does not apply to other plug-like devices. 

While I am old, ish, there was a time before, and I am sure it predates 1994 that you could purchase goods without a plug attached, the regulations required a fuse and plug to be fitted. This was of course because of the number of issues with badly wired, wrongly wired plugs… and magic smoke. apparently 1992 non plugs were outlawed… now we have a generation that cant wire a plug.. 🙂

We should also look into BS 646 in respect of the plug ( round pin) be that BS 3535.

Generators ( not specified)
OC 482/2: Electrical safety of independent low-voltage ac (hse.gov.uk)
BSI Technical Subcommittee GEL/107
BS CP 1013

“BS 4343 sockets are recommended. BS 1363 sockets, sometimes fitted to small machines intended for domestic use, are unsuitable for use in wet conditions.”
I would also read paragraph 8 to get some understanding of what is occurring, with interest to paragraph 11. of the above link.

In theory.

The plug pins will be live
while with a generator ( combustion) and non intelligence ( no computer control) would pump power to the pins, micro inverters switch off.
you can read this ( below link), though I do mention parts of interest.
Plug-in solar devices: With standards and seals (vde.com)

The inverter wont shut down fast enough.
I tested this myself; and it was hard to do to give a “best chance” to see if you could be shocked from the pins by removing the plug under load and getting the probes on as fast as possible. (deye Mi80– used with Mi relay).

GERMAN… Then English…

First standard for feeding into final circuits

Given the sheer number of the devices, plug-in solar generators can now be considered commonplace. That said, the familiarity of such products is no guarantee that they are safe. Using DIY methods, technical amateurs can use plug-in solar power systems to feed power into final circuits that were not designed for this purpose and lack corresponding protection. The DIN VDE V 0100-551-1 (VDE V 0100-551-1) installation standard for low-voltage installations was therefore revised in 2016 to cover the safety aspects of feeding power into household sockets.
The plug connections were a crucial point. The low-voltage standard requires them to protect users so that they do not sustain an electric shock from the contact pins. Along with a fixed connection, the standard requires a special energy socket for this purpose. The mains and system protection in the inverter, which prevents the feed-in of electricity if there is no frequency signal from the grid, does not in itself provide sufficient protection from electrocution.

However, since the norm has no legal force and there are few ways (particularly in single-family homes) to prevent people from plugging their devices into standard sockets, many solar plug-in operators have ignored this part of the rules.
 in early 2023 that called for simplifications to various standards. These would include a safe solution for enabling connections to standard sockets.

read more of the German standards and requirements:

E DIN VDE V 0126-95 (VDE V 0126-95):2022-11 (dke.de)

The British standard….

– on the load side of all the overcurrent protective devices for a final circuit of the installation, but in this case all the following additional requirements shall be fulfilled:

(i) The conductors of the final circuit shall meet the following requirement:
Iz ≥ In + Ig

Where:
Iz is the current-carrying capacity of the final circuit conductors
In is the rated current of the protective device of the final circuit
Ig is the rated output current of the generating set

(ii) A generating set shall not be connected to a final circuit by means of a plug and socket-outlet

How have issues been addressed?
It may not be shocking (no pun) but there is not finality, there has been a lot of work in the zero or 50V or less by means of a relay in the “micro inverter”, but there are concerns from the Swiss that they may not give protection in certain fault scenarios. VDE/DKE would suggest a separate type of socket. which eliminates the live metal ends of a plug socket.

What protection?
The “plug in” issue is a little more complex than you may first think.

In this consumer unit you will see the red mains switch (Right), and then two sets of MCB ( breakers/ fuses) the ones with the RCD ( with the little black button near the top on the right on the MCBS) is the protection down stream in the breakers.
In a scenario where there is a plug in solar, the source is the solar inverter which becomes upstream of the protection device and therefore renders all circuits unprotected.
in steps the RCBO.

The RCBO

An RCBO, which stands for Residual-Current Circuit Breaker with Overcurrent Protection, is a safety device that combines the functions of two separate components:

• Residual-Current Circuit Breaker (RCCB): This part of the RCBO detects leakage currents. Leakage current occurs when electricity flows unintentionally through a path other than the intended circuit, potentially leading to shock hazards. The RCCB can detect these small imbalances in current and quickly trip the circuit, stopping the flow of electricity and preventing electrical shock.
• Overcurrent Protection (OCP): This part of the RCBO acts like a traditional circuit breaker. It protects against overload situations where too much current flows through the circuit due to excessive power draw or a short circuit. In such cases, the OCP trips the circuit, preventing overheating and potential fire hazards.

By combining these two functionalities into a single unit, an RCBO offers comprehensive protection for electrical circuits. It safeguards against shock hazards caused by leakage currents and prevents damage from overloads and short circuits.

Upstream and downstream.. without water..

In an electrical system with dual power sources, upstream and downstream refer to the direction of power flow relative to a specific point or component. Here’s the breakdown:

• Upstream: This refers to the source side of the power flow. It’s the direction from where the electricity originates and enters the system you’re considering.
• Downstream: This refers to the load side of the power flow. It’s the direction where the electricity travels after it passes a specific point or component, ultimately reaching the electrical devices that consume the power.

Example with Dual Power Sources:

Imagine a building with a utility grid connection and a backup generator.

• Upstream:
  • For the utility grid connection, upstream would be the power lines feeding electricity into the building.
  • For the generator, upstream would be the fuel source (nuclear, diesel, etc.) that provides the energy to generate electricity.
• Downstream:
  • Both the utility grid and the generator feed into a common electrical distribution unit ( fuse box). From this point onwards, everything connected to the panel (lighting, appliances, etc.) would be considered downstream.

Key Points:

• Upstream and downstream are relative terms. What’s considered upstream depends on the specific point or component you’re focusing on within the system.
• In dual power source scenarios, you can have two separate upstream sources (utility grid and generator) feeding into a single downstream section (electrical panel and connected devices).
• The concept of upstream and downstream helps identify where power originates, how it flows through the system, and where it ultimately gets used.

Additional Notes:

• Sometimes, the terms “line side” and “load side” are used instead of upstream and downstream. They essentially mean the same thing.
• In some complex systems, there might be multiple upstream and downstream sections depending on how the power is distributed and managed.

By understanding upstream and downstream, you can better visualise the flow of electricity in a system with dual power sources.

The Final Circuit

In UK electrical systems, a final circuit, also sometimes referred to as a final electric circuit, has a specific meaning according to regulations. Here’s the definition:

• Final circuit: It’s an electrical circuit that directly supplies power to current-using equipment or to socket outlets for connecting such equipment.

In simpler terms, a final circuit is the last leg of the electrical distribution chain in a building. It’s the circuit that carries electricity directly to the appliances, lights, or other devices that use it.

Here’s a breakdown of the key points:

• Supplies Equipment or Sockets: A final circuit can either be wired directly to an appliance (like a fixed oven) or connect to socket outlets where you can plug in various appliances.
• Last Stage of Distribution: Power from the mains supply goes through various stages of transformation and distribution within a building. The final circuit is the point where electricity reaches its final destination for use by electrical devices.
• Protected by Fuse or Circuit Breaker: Final circuits are protected by a fuse or a circuit breaker. This safety device trips and cuts off power if the circuit becomes overloaded, preventing overheating and potential fire hazards.

Here are some examples of final circuits in a UK electrical system:

• A circuit that powers a specific lighting zone in a room.
• A circuit dedicated to a kitchen appliance like a dishwasher or refrigerator.
• A ring circuit, which is a particular type of final circuit commonly used in UK homes, that supplies multiple sockets in a room or across several rooms and is a loop (ring) that goes back to the starting point. (known as a ring circuit).
  

The conduction wires in a ring, are two 2.5mm2 wires with a earth ( known as twin and earth) the capacity of T&E is 25 amps, you will often see these fused at 32amps, because there are two paths in the ring.
The other type (RADIAL) is a single wire, older electricians could call these “spurs” or “branch circuit“, either way they are a single wire feeding X.

The area covered by a circuit shall be determined by the known or estimated load which must not exceed the nominal rating of the circuit protective device, and the floor area covered shall not exceed the area given in Table 1.

The total number of fused spurs is unlimited, but the following minimum cable sizes shall be used if a fused spur feeds the socket outlets.

• 1.5 mm2 for pvc insulated copper cables.
• 1 mm2 for micc copper conductor cable.

Fused spurs are connected to the ring circuit through a fused connection unit. The fuse of which must not exceed 13A, or the rating of the cable taken from the fused spur.

The number of non-fused spurs must not exceed the total number of socket outlets and stationary equipment connected directly in the ring circuit.

A non-fused spur can only feed one single or one twin socket outlet, or one permanently connected item of equipment.

What is the problem with solar feeding into the ring?

When you have a fault, the inverter to the source would NOT pass a RCD or breaker. therefore your body if that was a fault current would endure 13amps of current, and both the grid and mains power. feeding power though you rather than that 30mA of the RCD, while the type of protection varies if a fault occurs without protection or over load in the circuit.
When you have a fault, the inverter to the source would NOT pass a RCD or breaker. therefore your body if that was a fault current would endure 13amps of current, and both the grid and mains power. feeding power though you rather than that 30mA of the RCD, while the type of protection varies if a fault occurs without protection or over load in the circuit.

For example a 32 amp mains feed, and a 6 amps solar feed would inject up to 38 amps in to the circuit.
The 32 amp could fault 6 amps before seeing any difference to trip. also RCD’s are already known for failure with double faults.
However many hold the position of Downgrading the main breaker to 20 amps. The short fall being partly made up from the solar input on the circuit. a plug in solar of around 800W would add 4 amps breaking current.

– 20 amp circuit 4600w
– 13 amp circuit 2990w
– 6 amp circuit 1380w
-4 amp circuit 920w

What does it mean?
RenewSolar operates as a charity meaning that our income is drawn from consultations and advice given, this keeps our costs low and enables you to buy more or save money. if you would like to donate or purchase a consultation, you can via our shop.

Further reading:
While there are some details missing from this post, it is not meant to be the answer to how to install and perform an installation of any solar system. You can find out more about the electrical requirements here:
Delving into BS 7671: Section 712 and Solar Panel Systems — RenewSolar
Withstanding that the information does not cover what a DIY’er can or cant do and if you require a competent person to complete the work.