Metal roofs, due to their conductive properties, can act as unintended RF antennas. This effect is amplified when a metal roof is unearthed, increasing the likelihood of radiofrequency (RF) radiation hotspots. In these cases, the metal roof can pick up and re-radiate RF signals from nearby sources, creating potential hazards.

However, when properly grounded, metal roofs can serve as excellent protection against radiation. A grounded metal roof can shield the building’s interior from external RF and electromagnetic fields. This protective capability depends on the roof’s earthing, ensuring that any accumulated electric charges are safely dissipated into the ground.

One key risk of an unearthed metal roof is jump conduction, where RF radiation generates high electric fields. If these fields exceed a certain threshold, electric currents can arc across air gaps, leading to discharges. Without grounding, these charges can’t be safely channeled, increasing the risk of electrical events.

In addition, metal roofs often consist of different parts, such as sections at varying levels, which can create junctions or gaps. These discontinuities may exacerbate RF reception and hotspots, particularly if the entire system isn’t uniformly grounded. Electrical imbalances between the roof sections can lead to uneven charge distribution and increased RF pickup.

Moisture can further complicate this issue, especially in homes with rising damp. Wet conditions increase conductivity, degrade insulation, and elevate the risk of RF exposure, worsening the chances of jump conduction.

Proper grounding of all metal roof components is crucial. It mitigates these risks, ensuring that electrical charges are safely directed away, reducing potential harm from both RF radiation and moisture-related complications.

A metal roof with solar panels 

Grounding a metal roof with solar panels requires special consideration to ensure safety and avoid electrical issues.

Use a licensed electrician

Because grounding solar panel systems on metal roofs can be complex, it’s recommended to have a qualified electrician or solar installer ensure your system is properly designed and grounded according to local regulations.

By carefully managing bonding, grounding, and protection against potential issues like lightning and corrosion, one can avoid many of the pitfalls associated with grounding a metal roof with solar panels. Always prioritize safety by adhering to electrical standards and consulting professionals where necessary.

Some of the information and writing in this post were refined with the help of ChatGPT, an AI language model developed by OpenAI.

Further reading – 2 informative posts

•Jeromy Johnson The Dark Side of Solar

 ” I advise that ES people completely avoid solar unless they have shielded wiring and can put the panels / inverter away from the home and professionally filter the AC line coming into the home” Jeromy Johnson

Copyright Jeromy Johnson October 2017 – Draft, All Rights Reserved https://www.emfanalysis.com/wp-content/uploads/2017/10/Dark-Side-of-Solar-Draft.pdf

•Hugo Schooneveld – Tips for the low-radiation purchase and installation of solar panels

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A bit of common sense is required when converting to solar energy products.

Photovoltaic (PV) or solar cells convert sunlight into electricity. When light strikes the semiconductor material of a solar cell, it releases electrons that generate electric current.

A solar panel or PV panel is a frame with several connected solar cells. The more solar panels are connected together, the more electricity is produced.

Solar panels produce direct current (DC), not alternating current (AC) electricity. The voltage is also low, [for smaller domestic installations] and being DC, it is impossible for the solar panels which charge the batteries to create dirty electricity or harmful electric and magnetic fields.

In other words, the electrical power from the panels is low voltage (DC) and is not problematic.

The charged batteries power the inverter, which changes the current from low voltage DC to the 230v AC required in order to power the lighting and power circuits. This is where problems could occur.

The inverter should preferably be a pure sine wave inverter to match the requirement for the household appliances that are designed to operate on a pure sine wave ( the same pure sine wave as is generated by the power utility).

Non sine wave inverters have been found to give high readings on dirty electricity meters and sometimes these readings cannot be reduced by the conventional methods.

Claims of “pure sine wave” inverters might not be correct and technical advice may be required,

Needless to say that solar panels must be installed properly by a qualified professional to ensure for example that earthing has been done properly.

The electric and magnetic fields created by an inverter fall off very quickly with distance. Regardless, inverters should not be placed in areas where one spends time, or where a bed is located on the other side of the wall to the inverter.

This topic was included in EMFSA’s comments on the Parliamentary Portfolio Committee on Environment, Forestry and Fisheries; Climate Change Bill tabled in Parliament in February 2022:

“The bill should make strong provision for regulation of renewable energy products, for instance as EMFSA we have encountered some products that are advertised as generating a “pure sine wave” when in our opinion, it does not.” 

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