What you need to know about solar inverters and RF interference

A radio tuning dial

A solar inverter is like any other electronic device in your home and it will produce some Electromagnetic radiation and potentially Radio Frequency interference. There is a standard that all approved electrical devices in Australia are required to meet (C Tick) but it does not guarantee zero emissions.

The school is out on exactly what harm can occur to human beings from electromagnetic radiation but solar inverters do emit it, so if you are concerned ensure that your inverter is installed well away from living areas – as a rule Electromagnetic Radiation drops off very quickly as you move away from the source and is reasonably easily blocked by obstructions.

As a general rule, the biggest problems stem from Radio Frequency interference on AM or HAM radio because they rely on weak and variable signals with large antennae, which are particularly susceptible to interference of any kind but it doesn’t rule out solar for radio buffs.

Good installation practices to minimise EMR and RFI

The number one rule for EMR and RFI prevention are first and foremost – determine the real cause. Is it the inverter or something else? A simple hand held battery powered AM radio is a great tool to determine where interference is coming from.

Once you have found your source you can then revert to the golden rules – shielding, cancellation, filtering and suppression. Careful routing and location of the DC cabling (twisting them is a good general tip too) is a good idea and the location of the inverter can make a big difference.

Although it is dangerous to generalise, lower cost inverters (or other products such as power supplies) tend to have less filtering and EMR/RFI reduction equipment built in and are likely to cause more interference.  Some quality inverter web sites talk about their testing and the lack of EMF that is produced as a result of clever design; so some companies clearly invest more heavily in these types of issues.

So if you are really concerned about RFI or EMR, then I would strongly advise paying a few hundred dollars more to upgrade to an SMA / Aurora / Delta or other top quality European inverter from a brand that has had decades to tweak their designs. And make sure you ask the installer about the issue to weigh up his experience of this issue.

Reducing radio frequency interference is, at best, a “snipe” hunt but choosing quality gear and using installers who understand the issue will go a long way to minimising any impacts.

 

About Finn Peacock

I'm a Chartered Electrical Engineer, Solar and Energy Efficiency nut, dad, and founder of SolarQuotes.com.au. My last "real job" was working for the CSIRO in their renewable energy division.

Comments

  1. peter lalor says:

    my solar system when it first starts up and is closing down is interferring with my foxtel reception. the television makes a buzzing sound and a thin line appears on the screen at the same time. the sound is the same noise that is coming from the inverter, the inverter has been moved farther from the television but has not fixed the problem, do you have any suggestions or have you heard of this problem before thanks peter

  2. We recently had a solar system installed by a reputable company. We have a 5kw inverter. We are being blamed for problems with neighbours dial up internet and anything else that is going wrong electronically in our street. We have found that our AM radio is effected in our house only. Are we receiving the blame for problems that aren’t our concern?

    • Hi Sheryl,

      Your inverter cannot affect your neighbours dial up internet!

      Please ask the internet provider to send me the technical reasons for blaming solar for his crappy internet connection, I’d be fascinated to hear them.

      Yes, they can affect AM radio in your home. A toroidal magnet over the AC supply can sometimes help this. It looks like a hollow tube that clips over the outside of the wire. Costs about $2.

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