Internal PELD

PELD stands for Power Export Limiter device and limits the power output to a specified level. Autarco already provides a separately sold PELD which is mainly used for larger  PV-systems with multiple inverters.

For smaller systems with one inverter the Internal PEL feature can be used on our newest Mark-II inverters. This can be done with a separately sold energy meter (S2.1P-SMARTMETER.1 for 1-phase grade tied connections, S2.3P-SMARTMETER.1 for 3-phase grid tied connections) which is easily connected to the inverter. Once connected to the inverter, the internal PEL feature ensure grid exports are constantly measured and will not exceed the set value. A PELD can specifically be used to improve the business case of your customers in the following two cases.

  1. When power output needs to be limited because the internal AC device or grid can not handle a higher power out.
  2. When the grid operator (temporarily) demands that  no or limited energy may be supplied to the grid.

Click here to learn more about our newest Mark-II inverters


What is a digital twin?

The added value of our 'Digital Twin'

There is so much marketing jargon these days that it’s hard for us to use the term Digitized or “Digital Twin” without feeling like we’re trying to impress with hollow terms. That is why we have decided to explain a term often used by Autarco such as ‘Digital Twin’ in layman terms.

The added value of Autarco’s ‘Digital Twin’ is that it allows us to actively measure the weather-dependent performance of the system at 15-minute intervals. This accurate performance analysis allows us to verify whether installations are performing as expected. If this is not the case, we can respond quickly to problems through timely detection. The end result is an average performance improvement of 8% for residential PV systems and a 5% improvement for commercial systems.

What is the "Digital Twin"

The ‘Digital Twin’ is an exact digital replica of your physical system. It is created in our software, Helios, during the design phase of your project. It forms the basis for the system that will be installed on your roof, the yield we expect the system to have for the kWh guarantee and ultimately the price that the installer asks you to pay.

The ‘Digital Twin’ is designed on top of an elevation map that the designer can adjust to add or remove obstacles. Shade is modeled not only from a chimney on your roof, but also from the tree or hill behind your house.

How do we use the 'Digital Twin'?

Autarco uses the ‘Digital Twin’ to:

  • Verify that the installation is made according to the design and that it is correctly positioned. We can achieve a high level of trust through our remote verification, but we also rely on working with the best network of dealers who maintain high quality standards.
  • Detect defects or abnormalities that occur during the life of the system.

In short: the solar power system on your roof must match the calculation of the “Digital Twin” in terms of yield. If this doesn’t happen, something is often wrong.

Simple explanation in layman terms

We are now going to simplify some technical details of the ‘Digital Twin’ using children’s toys.

A solar power system consists of a number of “strings”, which are solar panels that are connected to each other in groups. They usually consist of six to 20 panels, depending on the system size.

In Autarco’s digitized inverters, each string is monitored individually and provides detailed information to our European cloud every five to fifteen minutes.

The information in these messages (voltage, current, power) creates a “shape” that constantly changes based on the actual system design, different shade levels, environmental conditions and possible product defects. You can compare each string in the monitoring message with a 3D block (see image below).

At the same time, the “Digital Twin” creates an expectation of the “shape” of each string. To do this, we use data that we receive from different satellites (irradiance, cloud cover and temperature) that we receive every 15 minutes to represent reality as well as possible. We can usually match this satellite data to less than 1 km from your actual location across Europe. Think of the expectation generated by the digital twin as the holes in the ball.

The monitoring messages are the 3D shapes that must fit into the holes. There is a hole and a shape for each ‘string’. If one of the shapes doesn’t fit in the cube, something is wrong and Helios automatically creates a notification in the system. We then check the system for defects.

Who else can do this?

No one.

Autarco is currently the only solar company worldwide that uses this technology.

How does Autarco calculate the expected yield?

How soon can you expect a return on your investment?

Renewable energy generated from natural sources such as wind and sun is a hot topic in the Netherlands. After all, we all have to become more sustainable in order to achieve the set climate objectives. The government stimulates this process with, among other things, subsidies and a netting scheme. This ensures that more and more houses, business premises, schools and factory roofs are equipped with solar panels. In short, the solar energy sector is thriving. However, individuals and companies do not place solar panels on the roof purely for idealistic reasons. The initial investment in a solar power system must be recouped. Preferably as soon as possible!

How is an expected return calculated?

The installer’s quote states an expected return on an annual basis and an estimated payback period. There are several models to calculate this with different levels of accuracy. At its core, however, the expected return is based on:

  • Historical weather data
  • The slope and azimuth of the roof
  • Shadow analysis

The historical weather data usually looks at data from the past 15 to 30 years and calculates an average from that. Add all these different factors together and it becomes quite a complicated calculation. Just because of the high degree of shade and a wide variety of roofs, there is often a considerable margin of error in this estimate.

The expected yield of your system is based on this long-term average, but due to annual variation in sunlight and temperature around this average, this can go up to +/-15%.

Very large projects typically make two types of yield estimates that take into account this variation in irradiance and other factors:

P50: The expected yield that will be achieved half the time

P90: The expected yield with 90% confidence.

Analysis of 20% of all utility projects in the US by kWh Analytics* shows that P90 production events, thus failing to achieve the stated efficiency, are actually three times more common than the P90 definition implies. The impact of these performance events on P90 is that the realized return is half lower than originally estimated.

Monitoring of current weather data is essential

While these P50 and P90 forecasts are useful for financial modeling prior to project construction, any reliable performance indicator needs to be adjusted to the weather once installed.

As you can see in the graph above, the Netherlands has had a higher irradiance in recent years compared to the historical average. Therefore, it is likely that underperformance of a solar power system will remain undiscovered. The system can achieve the expected yield stated in the quotation, but if it was an extremely sunny year, the system could even underperform by up to 15%.

At Autarco, we allow for some natural variation in modeling and data accuracy, and define any system that performs less than 95% of its weather-adjusted forecast as substandard.

Within the industry, weather-adjusted performance is measured through a metric called the “Energy Performance Index” (EPI). The EPI is also defined as the actual weather-corrected forecast of a solar power system.

This is where Autarco’s ‘Digital Twin’ and our data management skills make the difference. With other design software, the ‘digital copy’ is removed once the final quote and installation plans are generated. Our ‘Digital Twin’ remains active. We use this to verify the correct installation of the system and then to base the system’s performance on current weather data that we receive every 15 minutes for every square kilometer in Europe.

A monitoring portal only shows if a system is producing power, but does not provide a relevant benchmark for performance. That’s why Autarco’s kWh guarantee and weather-dependent performance monitoring are so important.

Autarco makes changes to its kWh guarantee

Systems with a kWh guarantee and active performance monitoring perform significantly better

Autarco is the only Dutch brand of solar power systems with an insured kWh guarantee. The value of this yield guarantee and the associated service and maintenance that is provided is enormous. Research into the performance of 5000 PV systems has shown that Autarco systems with a kWh guarantee perform three times better than comparable systems without.

Because we see an increase in the demand for revenue and PR (performance ratio) guarantees and operations and maintenance services, a number of things will change as of June 17, 2021.

Costs per kilowatt hour reduced

The free yield guarantee for the first five years after installation disappears. Instead, Autarco introduces two different kWh guarantees:

  • A Standard kWh guarantee insured by Autarco
  • A Premium kWh guarantee insured by the kWh guarantee fund foundation and Lloyd’s of London

Since the free kWh warranty for the first five years will disappear, the costs will increase slightly. However, this is more than offset by a reduction in the costs of yield guarantees for a period of ten or fifteen years. These are sometimes more than half cheaper.

Extra income for dealers through the sale of the kWh guarantee

Autarco dealers can generate extra income with the sale of the kWh guarantee. Autarco pays a commission for each kWh guarantee sold. There is also a chance of a performance bonus. This allows our dealers to benefit from recurring revenues and increase their net margin by up to 40%.

Operations and maintenance contract mandatory

For systems larger than 30 kWp, it is mandatory to conclude a service and maintenance contract. An Autarco dealer can choose to offer a service and maintenance contract themselves or have Autarco manage the service and maintenance.

Higher guaranteed return

We noticed that when the sun is low in the sky, we estimate the production of the solar panels too high. On an annual basis, our indication was correct. To make our calculations even more accurate, we’ve introduced things like angle reflection and an improved model for shading between the rows. This makes it possible to calculate the expected yield of a solar power system even more accurately than before. That is why we can now issue a higher yield guarantee.

P.R. Guarantees

Autarco will now also issue fully insured Performance Ratio (PR) guarantees to customers based on current satellite data. PR guarantees will only be issued for PV systems larger than 30 kWp.

Generate additional income by selling the Autarco kWh guarantee

How to monetize the kWh guarantee?

Autarco dealers can now generate additional income from the sale of the kWh guarantee starting the 17th of June 2021. For each kWh guarantee sold, Autarco pays a commission of 10% of the total amount to the dealer. There is also a chance of a performance bonus if the installed systems generate high yields. This allows our dealers to benefit from recurring revenue and increase their net margin by up to 40%.

Additional income

Autarco dealers can extend the customer lifecycle with the sale of the kWh guarantee and operations and maintenance packages (O&M). For projects larger than 30 kilowatts, the purchase of a service and maintenance package in combination with a kWh guarantee is mandatory. In this way we guarantee safe solar power systems that perform well.

Various constructions are possible in which:

  • Autarco issues the kWh guarantee to the end customer and Autarco provides full service and maintenance.
  • Autarco issues the kWh guarantee to the end customer and provides the dealer with service and maintenance.
  • Autarco issues the kWh guarantee to the end-customer and no O&M contract is required (only for systems less than 30 kilowatts!)

Depending on the sold construction (kWh warranty and Service & Maintenance), the dealer receives at least a commission of 10% of the total sales amount. This commission is paid annually or once every five years. There is also a performance bonus for dealers with systems that deliver between 100 and 115% of the estimated return.

For instance:

A 250 kW Autarco system with 15 years of standard service and maintenance and a 15-year premium guarantee (0.10/kWh) can generate a total of € 6,000 in recurring revenues (0.024/Wp).


If a dealer installs three Megawatts of Autarco solar panels per year with 15 years of standard service and maintenance plus a 15-year standard guarantee (0.10/kWh), this can generate a total of € 27,000 in revenue. If the systems perform above average, the dealer will also receive a performance bonus of € 9000.

If the same dealer sells the Premium kWh warranty instead of the standard kWh warranty, the commission will increase to 36,000 over a period of 15 years.

“By selling the Autarco kWh guarantee and O&M packages our dealers can increase their net margin up to 40%”

Dan Horan, CEO Autarco

A standard and premium guarantee

Autarco offers customers the option to choose from two different kWh guarantees:

  • A standard kWh guarantee insured by Autarco on a portfolio level
  • A premium kWh guarantee insured individually by the kWh guarantee fund foundation and Lloyd’s of London

Insuring the yield of a solar power system is possible from € 0.10 per kWh with a standard kWh guarantee.

About Autarco

Autarco is the only producer to supply a solar energy system in which all components are developed in-house and therefore connect seamlessly. Thanks to this total solution, Autarco can also offer the kWh guarantee, with which you are guaranteed to save on your energy bill in the long term.

The performance of your Autarco system is insured through the independent Stichting kWh-guarantee fund in collaboration with the world’s largest insurer Lloyd’s Of London. Is the system underperforming? Then the difference is simply paid out in cash per kilowatt hour missed.

45% of solar systems underperforms

Systems with an insured kWh guarantee and active performance monitoring perform three times better.

An analysis of nearly three thousand bankable residential roof systems in the Netherlands, looking at performance data up to 8 years ago, shows that only 55% of the systems without a kWh guarantee achieve the expected yield. On the other hand, systems with a kWh guarantee provide better performance. 85% of the systems with a kWh guarantee perform as expected or even exceed expectations. Of course, a kWh guarantee does not in itself improve the performance of a system, but the processes and software that make this guarantee possible do.

Design and system checks

After the design and installation of a residential solar power system, the majority of solar installers in the Netherlands spend hardly any energy on O&M. Whether your solar panels actually deliver the estimated yield and are installed correctly remains uncertain.

Larger PV systems of over 5 Megawatt (more than 10.000 panels) are better maintained and monitored, however, for example, an analysis of 20% of all utility projects in the US by kWh Analytics* shows that P90 production events, i.e. not achieving the stated efficiency, are actually three times more common than the P90 definition implies. The impact of these performance events on P90 is that the realized return can be up to half of what was originally estimated.

Unnecessary loss of yield

The outcome of Autarco’s study shows that, even when using high quality products, in many cases this loss of efficiency can be prevented with good maintenance, supporting software and accurate use of (historical) weather data. After all, based on this, we are able to  issue our high insured kWh guarantee.

What sets Autarco apart

During the design phase of a solar power system, Autarco makes a ‘Digital Twin’, or a digital copy, of the physical system design. Before we issue a kWh guarantee, every new system is verified against this Digital Twin. For example, we check the installation plan and the complete installation of the inverter and solar panels. This ensures that the system is installed safely and according to the correct specifications.

Even after installation and issuance of the kWh guarantee, Autarco continues to monitor each system. If a solar power system performs less than 95% of what it should deliver according to the ‘Digital Twin’, we will contact the installer so that he can check the installation again and solve any problems. Autarco only provides this aftercare for solar power systems with a kWh guarantee.

Weather-corrected forecast

The Netherlands has had a higher irradiance in recent years compared to the historical average. Therefore, it is more likely that underperformance of a solar power system will remain undiscovered. The system can achieve the expected yield stated in the quotation, but if it was an extremely sunny year, the system could still underperform by up to 15%.

At Autarco, we allow for some natural variation in modeling and data accuracy, and define any system that performs less than 95% of its weather-adjusted forecast as under-performing


Autarco bases its conclusion on data from 2679 solar power systems, of which 1638 have a kWh guarantee and 1041 do not. The systems without a kWh guarantee have not received a professional check after installation. These systems also lack corrected performance monitoring based on current weather data. The investigated solar power systems consist of Tier-1 quality solar panels and inverters.

These systems are using identical hardware with a common set of installers. The only material difference is whether the system has received the special care and attention that Autarco gives to systems with a performance guarantee.

Our findings are also supported by an expanded 2020 Energy Validation Study completed by DNV GL, a leading energy consultant and engineering firm, that demonstrate that the median performance of commercial projects  below 50kW is only 94.6%.

MHJ serie zonnepanelen

Autarco introduces solar panels with a maximum power output of 410Wp

Autarco introduces solar panels with a maximum power output of 410Wp

MHJ serie zonnepanelen

MHJ series

Autarco introduces the MHJ series solar panels. Efficient solar panels with a maximum power of 410Wp and dimensions of 1708 x 1133 millimeters. The panel features 108 cells, each measuring 182 x 91 millimeter. The MHJ series comes with a 25-year insured linear power guarantee of up to 84.8%.

The solar panels of this MHJ series use semi-cut monocrystalline PERC cells with advanced multiwire technology to deliver higher efficiency without sacrificing reliability at a nominal voltage of 1500V DC. The panels have an innovative design with a high power output of more than 212 Wp / m2.

Mounting solutions

The MHJ Series delivers a higher power module without causing headaches on the install side. The low weight (21.5kg) and short length (1708mm) make it perfect for pitched roof and small-medium commercial projects. All mounting materials are automatically proposed based on the digital twin in our design software Helios. 

When installing on pitched roofs new rail lengths will be proposed to match the new module widths. For flat roof systems, there are new base units, carriers and carrier supports.

80% of sales

The MHJ series panels are already available in Helios, Autarco’s design portal, and will be available for delivery in September 2021.

In addition to the MHJ series, we will soon be introducing three more panels that use 182mm and 210mm cells with a maximum power output of 450 Wp, 500 Wp and 605 Wp. As the market for solar panels develops, we expect that by 2022 80% of our turnover will consist of the sale of these 182 x 210mm cell panels.

About Autarco’s Total Solution

Autarco is the only manufacturer to supply a solar energy system in which all components are developed in-house and therefore connect seamlessly. Because of this total solution, Autarco can also offer the kWh guarantee, with which you are guaranteed to save on your energy bill in the long term.

The performance of your Autarco system is insured through the independent KWH Guarantee Fund Foundation in collaboration with the world’s largest insurer Lloyd’s Of London. Is the system performing less? Then the difference is simply paid out in cash.

Intelligent energy solutions by Autarco and Tigo

Intelligent energy solutions by Autarco and Tigo

For rooftops with a lot of shade, or in cases where insurers require that the voltage of the solar power system can be reduced to a safe voltage, Autarco, in combination with Tigo optimizers, offers a highly intelligent energy solution where safety and cost efficiency are paramount.

In addition to major cost benefits and lower installation costs, our intelligent technology reduces the risk of errors and connector mismatch. Autarco is the only Dutch brand that offers a total solar solution in which all parts are developed in-house. This way we can guarantee that all connectors of an Autarco system are equipped with original MC4 connectors from Staubli. This relatively small adjustment significantly reduces fire risk and makes Autarco systems one of the safest on the market.

The benefits of these optimizers

Great cost benefits in the calculation

The biggest advantage of Tigo, in combination with Autarco, is that only the panels that suffer from shadow fall need to be fitted with Tigo optimizers. But then you must be able to determine which panels these are! This is very easy with the Helios software from Autarco.

The result: savings of up to 10,000 euros on a 150 kWp system compared to a SolarEdge system, for example, where the entire roof is always provided with optimizers, even though most panels do not suffer from shade.

For instance:

  • A roof with 500 panels, of which only 20 panels are shaded.
  • 250 SolarEdge duo optimizers, cost € 12500 (estimate)
  • 20 pieces of Tigo optimizers, costs € 540

The saving is therefore almost € 12,000 in material costs. This does not even include the additional installation costs of installing 230 optimizers.

Selective application with different Tigos

Autarco works with both the Tigo optimizer (TS4-A-O) and the safety module (TS4-A-S). These two products differ in function but also in price and can be used in combination in a solar power system. If an insurer requires that the entire roof can be switched back to low voltage immediately, then you only apply optimizers to the panels that are actually in the shade. On the other panels you apply the cheaper safety modules, which only ensure that the panel goes back to 1V when necessary. The combination means that you can optimize the business case for your customer because you are more specific and cheaper but just as safe!

Lower installation costs

In cases where there is only limited shade on the roof, an installer can save considerably on installation costs, as far fewer Tigo optimizers are installed.

Less chance of errors

It is often underestimated: optimizers increase the risk of errors because there is more electronics on the roof. Using the Helios design software developed by Autarco, users are able to reduce shadow drop to less than 5% loss in most cases. In such a case, it is not economically profitable to include optimizers in the system because the additional returns from optimizers do not contribute positively to the business case of your customer. A normal system with string inverter in combination with the kWh guarantee guaranteed by Lloyd’s of London is the best solution.

Why? Optimizers are precious. In addition, with optimizers you increase the number of connections on the roof and electronics are placed on the roof, which can also break. Because Autarco, in combination with Tigo optimizers, minimizes the number of optimizers required, and precisely adjusts it to the actual economic need, such a system is less susceptible to malfunctions than, for example, a SolarEdge system with many more optimizers on the same roof surface.

Module level rapid shutdown and arc fault detection

Tigo optimizers (in combination with Autarco), like competing systems, have the option to switch high voltage on the roof back to a safe voltage if necessary (or required by insurance). All Autarco inverters are also equipped with arc fault detection.

But with Autarco, arcs are not only detected. They are also prevented. In a SolarEdge system,different makes of MC4 plugs are clicked together. An Autarco system is much safer, because Autarco only uses original Staubli MC4 plugs on panels, inverters and Tigo optimizers.

Autarco, in combination with Tigo, offers a full-fledged solution that ensures that the risk of fire due to electric arcs and connector mismatch is minimized, while any extinguishing work can be carried out safely because there is no high voltage present.

About Autarco

We are a Dutch company specialized in solar power solutions for pitched and flat roofs. As a solar producer we focus on what we are good at: innovation and delivering optimal total solutions. We have a strong network of Authorized Dealers who are specialized in the installation and maintenance of Autarco solar power systems.

The advantages of an Autarco system at a glance:

– One complete solar power system (solar panels, inverters, mounting system, monitoring software, cables, connectors, etc.) from one Dutch brand.

– Unique kilowatt-hour (kWh) guarantee insured by Lloyd’s of London

– 24/7 system monitoring

– Seamless integration into the Helios design system

– Asset Management

– Monitoring per panel possible via the Tigo portal


Increase in irradiance levels during lockdown

Did Netherlands Covid-19 lockdowns affect the performance of solar systems

On March 15, the Dutch PM announced that “All schools, cafes, restaurants and sports clubs will be closed in the Netherlands to stop the spread of coronavirus.” 3 months of hard lock down that most of us would happily forget followed. As we find ourselves starting to emerge from a second lockdown and starting to see light at the end of the tunnel it’s a good time to go back and see if we can find some positives from a difficult time.

It is reasonably well established that the natural environment benefited from a reduction in human activity during lockdown periods across the globe. Two of the most known examples are the clearing of the canals in Venice (some say the return of birdlife was also a result, but any one who has been to St Mark’s square knows there are plenty of birds in Venice!) and the reduction in pollution over Wuhan.

But what about the more direct impact on solar systems in the Netherlands? The graph below shows a clear increase over the 5yr and 30yr averages for the lockdown periods.

Impact of Dutch lockdown on irradiance

Graph 1

Irradiance overview Netherlands

Graph 2

The irradiance levels in April and May increased on the 30yr average by 29% and 24% respectively. These values are at the extremes at what would be expected based on normal variation in weather conditions, but are theoretically possible. It is worth noting that the combined irradiance of April and May achieved in 2020 has not been exceeded since records began in 1983! Statistically these sunlight levels could be considered a 1 in 50 year event.

As the lockdown began to ease at the beginning of June the irradiance levels returned to their long term averages, which in our opinion provides further evidence that the lockdowns did in fact contributed to higher irradiance levels throughout the Netherlands.However, while the data certainly suggests a direct impact, the natural variability makes it difficult to conclusively state that this is caused by the lockdowns.

Irradiance variation is widely misunderstood and the effects on performance under-estimated.

Graph 2 shows that during the boom years of Netherlands solar, irradiance levels have consistently been above the long term averages.

When an expected yield is provided for a system in design phase a long term average of irradiance is used (more on P50 andP90 later). Over the past 5 years actual irradiance has been 10% above historic levels in the Netherlands, the logical expectation is that system performance should be over achieving the expected yields provided pre-build by 10%.

It is difficult to predict future trends in irradiance, clearer skies obviously have a positive impact, but there are also much larger climate and weather affects that influence these trends. A return to historic averages, or even lower, are very likely within the SDE timeline of projects being built. When this happens, we expect a lot of rooftop asset owners will discover their systems, they thought were doing well by meeting expectation are actually underperforming, and have been ever since installation. 

For larger ground mount systems and the largest industrial rooftops with owners who are solar professionals, pyronometers are used to measure on site irradiance and monitor relative performance, but these level of sophistication remains quite rare for the majority of SDE projects.

The Autarco way

At Autarco, all of our performance metrics are based on actual irradiance data that we receive in 15min intervals for all of Europe. Using the digital twin in Helios, this irradiance data is used to generate true expected values (or retrodicted for the nerds). This Delivers a true base line for performance (referred to as Energy Performance Index (EPI) and ensuring all our systems are generating at optimal levels. It’s just one more example of how we use the power of data and digitilisation to deliver on our promise; “Solar made simple. Performance made certain”

Arc fault detection and application

The risk of fire caused by solar systems is very low and in the vast majority of cases caused by low quality products or installer errors that lead to an electrical arc and then fire. The chance of a fire being caused by an arc in your solar system is comparable to the same risk carried by most electrical appliances such as a TV.

Despite this low risk, at Autarco we have taken all possible steps to reduce risk. As a total solutions brand, we are in position to control these risks far better than a brand that only produces one product like a solar panel manufacturer or solar inverter manufacturer.

Read on to find out more.

What is an Arc Fault?

An arc is formed by separating two parts of a circuit where a current is running. A plasma is formed between the 2 parts emitting light and heat. The plasma is a good conductor, so in other words the current will keep flowing and the arc will continue until one of below;

  • The voltage in the circuit is reduced to less than 12V
  • The distance between the 2 parts is closed
  • The distance between the 2 parts is increased far enough to break the arc

In a solar system, the rooftop current is a direct current which makes arcs more troublesome than in an AC circuit where the voltage goes to zero (50-60 times in one second, according to the grid frequency).

The large energy produced by arcs can be controlled in certain industrial applications such as welding and plasma cutting and they are also commonly used in lighting applications. If uncontrolled, the hot plasma may cause damage and will cause plastic parts to melt and potentially cause fire.

Possible causes of an arc in a solar system

There are numerous connection points in a solar system that are potential flash points for electrical arcs to occur. You can think of these points simply as switches and plugs.

Individual solar panels have connectors (plugs) on the end that are joined together. The ones that come on the solar panels are installed in highly automated production lines with stringent quality control. The installer just needs to make sure they hear a “click” when they connect the plugs and then the risk is incredibly low.

The connectors on the cable that connects the panels on the roof to the inverter on the ground are added by the installer and this introduces two risks;

  1. They use a different brand of connectors to those on the solar panels
  2.  They do not install the connectors properly.

As a total solution brand, Autarco uses approved dealers and provides all connectors of the same brand to our professional install partners.

Some form of DC switch is mandatory at the solar inverter, so the inverter can be safely disconnected from the solar panels for maintenance etc. Often referred to as a DC Switch or DC Isolator.

  • When an installer is not suitably trained or is trying to save costs they may install an external switch that is not suitable for the solar system which can result in arcs.
  • Beyond incorrect product choice, the connections in the external switch may also be poorly done. Autarco dealers and installers receive instructions how to install these switches properly.

Autarco inverters have an integrated DC switch, so they are always properly matched and installed under strict quality control.

External Causes
Animals chewing through wires can also lead to arcing. By proper separation of the DC-cables, propagation of the arc is prevented.


Prevention beats detection every time. That’s why we have deployed innovative technologies and processes in our total solutions to mitigate the three main causes of unsafe situations.

  • Product Quality
  • Design Safety
  • Install Quality

You can read more about this on our safety page.


In addition to our prevention measures, new Autarco inverters are now available with inbuilt Arc Fault Detection. This means that the inverter can detect an arc in line and will then shut down and send an alarm.

The detection in Autarco inverters conforms with UL1699B-2018, which is an American standard, but is currently the only available standard for arc fault detection in the world. As new standards (the European organisations are working on one now) become available, our inverters can be upgraded to comply with them.

There is still an additional risk: if the sun is shining there is always a voltage between the panels even if the inverter shuts down, so the arc may not be extinguished by inverter shutdown. By adding optimizers to each solar panel it is possible to reduce voltages of all panels on the roof to a safe value.

Read more about Autarco and safety

Interested? Get a free roof scan and follow up from one of our Authorized Dealers near you.

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