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.

  3. Your solar system can affect your neighbors wireless internet connection!

  4. Hi Finn,
    I am putting a 5Kw Fronius 3 Phase inverter on the wall in my garage, the only concern I have is that my study and PC are on the other side of the same wall. Can I use shielding like Aluminium foil or copper mesh to create a primitive Faraday cage and shield my PC from any EMR? My other concern is that this could promote arcing from the incoming DC cables.

    Your thoughts,
    Marc

    • Great question – short answer – I don’t know! I’ve asked around and I’ll let you know when I get an answer. Watch this space…

      • Thanks Finn, I’ll keep an eye out for your reply.

        Marc

        • Hi Marc,

          Here’s the reply (I don’t think RF will be an issue):

          “I do know of one Sungrow inverter that messed with radio signals out in a rural area, and Enphase and particularly Solar Edge regularly mess up tv signals. (MLPE near the aerial).

          I’ve never heard of an issue with Fronius and we have installed and monitor about 180 Primo’s and Symo’s to date.”

          • Anna Wilkins says

            Hi Finn,
            We are having lots of trouble with our Enphase inverter affecting our neighbours TV, do you know of anyone that was able to successfully resolve this? It is starting to cause some tension.
            Thanks
            Anna

          • Finn Admin says

            Hi Anna,

            I asked Enphase about this they said:

            “This issue has now been resolved. It’s not an overly widespread issue but it does occur in some cases where poor TV reception is in play before the solar installation. It is resolved by improving the tv signal by replacing the antenna with a modern one.”

            Enphase say they will happily resolve your issue for you – just ask your installer to advise Enphase about the issue.

            Any issues – let me know and I’ll ask Enphase to contact you direct.

            Finn

  5. JiM madigan says

    Hi Finn.
    To get ‘approved’ status, CEC approval – listing – for grid connect inverters, requires certification by ACMA for EMC and EMR.

    Are there inverters being connected that do not meet the ASNZ standards for EMC / EMR ?

  6. jim madigan says

    Finn.

    Thanks for your response but, it doesn’t answer the question.

    Are inverters being connected (sold) that do not meet the ASNZ standards for EMC/EMR. ?

  7. We recently had a SolarEdge inverter system fitted. Since then we have had TV and radio interference, especially in the middle of the day when the inverter is working more or less at capacity. The original installer then moved our antenna slightly which made a slight improvement at the beginning and end of the day. Today we had a new digital antenna fitted at the rear of the house, further away from the inverter. Again it improved things but we still get interference in the middle of the day, making several channels unwatchable (although interestingly, different ones to previously). The supplier, a reputable company, has been supportive through this process but states they have not had any other customers report this problem with SolarEdge and the antenna guy today, who is also a solar installer, stated he had not seen this problem before. The SolarEdge paperwork does however state that there may be interference. I am not sure if this is because SolarEdge has microinverters or what is the cause??

    • Bronte Parkin says

      Hi
      Did you resolve this issue? I’m interested because I too recently had a Solaredge inverter installed and have lost all ABC channels ie those with weaker signals in Perth. Tv guys came today and were nconclusive, so I’m left up in the air still!

    • Hi
      Did you resolve this – this is exactly the same issue we are having with SolarEdge system.
      Cheers

  8. Hi Finn,
    I am a Ham Radio Operator and would like to know what is the up to date brands you would recommend for inverters with low EMC/EMR?

    • Ronald Brakels says

      Hi Nutters, Ronald here.

      All inverters have to meet Australian standards for EMC/EMR. This means they should give off very little. But which ones give off the least, I am afraid I don’t know. EMR can be limited by placing it in a ventilated tin box or behind fine wire mesh, but obviously it would be more convenient if you didn’t have to do that.

      One thing that has been known to cause interference with people’s TV signals are solar panels with panel string optimization, such as Maxim optimization:

      https://www.solarquotes.com.au/blog/maxim-just-killed-microinverter-dc-optimiser/

      So you may want to avoid them.

  9. Our inverter is on a timber wall back to back with our nbn equipment, the inverter intanet connection which we havent used takes over our ipads and laptop we have selected forget this but it still seems to come up like our provider to the point i had to turn the inverter off to actually get on line

    • Bronte Parkin says

      I wrote above on 18 August. Since then, after testing TV signal strength all over our roof, TV technician ascertained that the interference with our signal was coming NOT from the inverter/s (we have two side by side), but from the panels themselves (Canadian Solar – optimised versions) – perhaps reflecting the signal? Solution was a new digital antenna located on leading edge of gable away from the panels, with new cabling to internal TV points. Result is clear picture during daylight hours!

  10. Hi Finn,

    Very interesting article and may have answered an issue we are facing.

    I have a few lights which are controlled via microwave motion sensors. These are mounted on the ceiling, above which there is a fairly large solar system (I can find out about the system capacity if necessary). The lights/sensors behave erratically. The sensors keep triggering the lights randomly even when there is no one in the space. There are no problems with the lights or sensors, which we checked numerous times.

    Would the high frequency noise from the inverters confuse the microwave sensors into thinking there is motion? I believe microwave sensors work by transmitting microwaves and checking the phase change in the frequency upon receiving them.

    Cheers,

    Ash.

  11. Michael Boyd says

    Hi Finn

    Recently had solar installed with solar edge. Now my TV channels are dropping out when the solar is working. The installer is say it is because of weak TV reception and is sending a TV antenna guy to check this out. Still waiting. Sounds like the problem is out there with solar. Maybe your team can find an answer.

    • Ronald Brakels says

      Hi Michael, Ronald here.

      I found this from SolarEdge on radio interference:

      https://www.solaredge.com/sites/default/files/feed-in_limitation_application_note.pdf

      They suggest:

      Reorient or relocate the receiving antenna.
      Increase the separation between the equipment and the receiver.
      Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
      Consult the dealer or an experienced radio/TV technician for help

      Their fourth point — consult the dealer — should be the first step here in Australia. Under Australian Consumer Law, our Consumer Guarantees say products must:

      – Be safe, lasting, with no faults

      – Do all the things someone would normally expect them to do.

      Clearly, one would not expect a solar system to interfere with TV reception and they should relocate or replace your antenna or do what ever else is required to remedy to problem.

  12. Paul Turnock says

    Hi Finn or Ronald

    I have a TV and an NBN satellite dish on my garage roof with coax cables travelling about 15 metres to the house.
    I am about to install 10 LG 335W panels (with 10 SolarEdge Optimisers) on the garage roof.
    Subsequently the DC cables will run back to the house for about 15 metres before connecting to a SolarEdge HD Wave inverter.
    At one point, during this panel to inverter connection, the DC cables will run side-by-side with the existing coax cables for about 4 metres.
    Will this particular 4 metres of parallel cable and proximity situation cause EMI problems?

    Thanks (as always)
    Paul

    • Ronald Brakels says

      Hello Paul, Ronald here.

      DC cables should definitely not cause EMI problems. DC current produces stationary standing waves so there should be no real possibility of interference.

      But I will warn you that some people have experienced TV and radio reception problems after installing optimizers. Generally this is only an issue when the signal being tuned into is weak. I would assume your NBN dish will be fine, but it’s not something I’ve had experience with.

  13. Ethel Hope says

    My neigbours installed solar micro inverter panels a few years ago I had trouble with channel 2 and SBS so called TV repair man He changed aerial and booster then told me my neighbour had a faulty inverter but they tell me they have micro ones As soon as the sun hits the panels the pictures break up. is this normal?

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