[RFI] Solar Power: Where we stand. Was Re: Noise from Generac Solar controllers?

[Hare, Ed, W1RFI]

Thanks for clarifying, Dave.  When I saw some of the incorrect information taking on a life of its own, I needed to jump in, although it is just luck that I managed to read this deep into the thread.  The ARRL Lab is running shorthanded right now and I don't have as much time for these lists as I might like.

First, the regulations.  To summarize:

o    Home solar systems are digital devices, classified as unintentional emitters under Part 15.
o    Home solar systems do not meet the criteria to be categorized as devices that are exempt from the emissions limits.
o    Large "solar farms" are also digital devices, but because they are power generation not connected to residences, they COULD be classified as exempt from specific limits.  That has never been tested, but we do need to keep that in mind.
o    Under the rules, these solar systems are authorized by a Suppliers Declaration of Conformity, or, optionally, certification.
o    An SDOC is essentially a self-validation, where the manufacturer issues a statement that it complies with the rules.  For the most part, from all indications, these devices do.
o    Under the Class B rules, devices that are not exempt must meet conducted emissions limits onto the AC mains below 30 MHz. They must meet radiated emissions limits above 30 MHz.  The conducted noise onto the wiring to the panels is not regulated by Part 15.  From all we can tell, the solar systems being marketed do meet the letter of the emissions limits rules.
o    Manufacturers are responsible for having designs that meet the emissions limits and for marketing them appropriately.  For example, a solar system could be designed for installation on businesses in a way that met the higher commercial limits, but it must be marketed only for use in commercial environments.
o   These are the ONLY EMC requirements that the manufacturer must meet.
o   The rules also stipulate that otherwise-legal devices must not cause harmful interference to licensed radio users such as amateur radio, CB, broadcast reception etc.  This is a requirement that is placed on the OPERATOR of the solar system, ie a neighbor, the ham him/herself or, in some cases, the utility or third party.  So, when a manufacturer steps in to address harmful interference, it is doing more than the rules require.  This is important to know.

Those who observe that the limits are high are correct.  If a "barely legal" Part 15 device of any sort were operated in the home of a neighbor 100 feet away, for example, noise around S7 would be typical, plus or minus.  Almost all of the cases that ARRL takes to the FCC are moved forward on the basis of harmful interference, making measurements of conducted and radiated noise irrelevant.  The FCC has taken that issue seriously enough to authorize considerable staff time to writing a good number of advisory letter, so it does care, but needs help to direct its resources efficiently.

Now, part of the crux of the issue is "harmful interference." Not every noise is harmful interference to the FCC.  The definition is vague, and we want it to stay that way.  If we were to ask the FCC to draw a firm line in the sand and set a level for "harmful interference," it is almost certain that the FCC would draw a line we don't like.  If, for example, it drew the line at the current conducted and radiated emissions levels, we would be looking at some pretty serious noise.

There is, of course, ambient noise everywhere.  The median level of man-made noise on HF ranges around S6 on the lower bands, S4 on the higher bands.  Harmful interference complaints below this level are usually not well received by the FCC, under the principle that half of the locations in residential environments have this noise level half of the time on half of the frequencies, so even when noise levels changes, it considers the noise to be typical of noise everywhere.

This doesn't mean that hams are always stuck. To the contrary, all three of the solar companies I am working with is looking to reduce the noise from their systems as low as can be done, although below the levels I described, this is still a work in progress.

So the bottom line is that hams can relief, effectively for strong noise sources, and, in the long run, hopefully at lower noise levels as well, with the industry going over and above, or under and below, what the regulations or FCC would mandate if pressed.

This is much like the BPL days, when parts of the industry resisted notching the ham bands, but other parts implemented those notches, to good effect. That got picked up internationally and made part of the ITU requirements for BPL. So, in the US, we "lost" the regulatory battle, but behind the scenes, worked with the "good guys" who helped bring the effective EMC solutions to the table internationally.

We are seeing the same sort of thing with the solar companies that are involved in interference complaints doing more than the rules require and looking for ways to do better yet.

As I have learned in my industry standards work, this is the real way things get done, because all the rules in the world are not enough, but cooperation and reasonable expectations and a bit of patience are. I was patient for 14 years with BPL and, in the long run, not only did it solve the problem, but that patient and technically honest approach built the reputation of amateur radio to the point where our presence in industry circles is both welcome and wanted, with amateurs elected to leadership positions in major industry organizations and committees. (For example, ARRL is a member of the C63 EMC Committee, chairing subcommittees, writing standards that are incorporated by the FCC into its rules.  I also serve on the IEEE  EMC Society as its Vice President for Standards. All of this was possible because we took a steady and technically correct approach to helping to solve problems.

Ed, W1RFI



________________________________
From: David Eckhardt <davearea51a at gmail.com>
Sent: Thursday, December 16, 2021 6:19 PM
To: Hare, Ed, W1RFI <w1rfi at arrl.org>
Cc: Ken Bandy, KJ9B <ken.kj9b at gmail.com>; Rfi List <rfi at contesting.com>
Subject: Re: [RFI] Noise from Generac Solar controllers?

Yes, I may have jumped to conclusions too fast based on what I wanted to see.  Apologies to everyone on the RFI list.  I've been out of it in retirement for some 11 years and am not as sharp as I once was.

However, I do have a LOT of problems with the whole solar power industry ignoring what they know to be true.  The statement from SolarEdge confirms that wrt "HAMS".  Until they are called on the carpet, nothing will be done - remember BPL.  In that respect it seems that ARRL has assumed the role of the old FCC I once knew when first licensed in 1960.  Sad, but ARRL is highly capable.  Just that my patience is wearing thin wrt the solar power industry and RFI.  Sure, it costs money and better and more rigorous instructions for instals.  But, come on......!  We have enough RFI coming in from China with no attention (or ignoring) EMC/RFI requirements.

This is all from me for this thread.

Dave - WØLEV

On Thu, Dec 16, 2021 at 10:24 PM Hare, Ed, W1RFI <w1rfi at arrl.org<mailto:w1rfi at arrl.org>> wrote:

You are not “well aware” if you were looking in the FCC certification database for reports on digital-devices unintentional emitters.  They are not required to file anything into the certification database.

I do not find the words “Class C” anywhere in Part 15.  There are Class A industrial devices and limits and Class B residential devices and limits.  You may be talking about the section in Part 15 Part C, intentional emitters. Those are certificated, but Part C devices are not industrial devices; that is the description of intentional emitters.







From: David Eckhardt <davearea51a at gmail.com<mailto:davearea51a at gmail.com>>
Sent: Thursday, December 16, 2021 5:17 PM
To: Hare, Ed, W1RFI <w1rfi at arrl.org<mailto:w1rfi at arrl.org>>
Cc: Ken Bandy, KJ9B <ken.kj9b at gmail.com<mailto:ken.kj9b at gmail.com>>; Rfi List <rfi at contesting.com<mailto:rfi at contesting.com>>
Subject: Re: [RFI] Noise from Generac Solar controllers?



Yes, ED, I'm well aware of all that.  In my looking at all the reports filed with FCC, none addressed the complete system, only the intentional radiators (Zigibee, BlueTooth, or whatever).  Yes, as a Class B filing, no report is necessary.  They must have modified those wireless modules, likely the antenna or digital format, to require testing and approval.   No one in their right mind as a user of widely available wireless modules wants to own the FCC approval for those.  Let the suppliers own the regulatory requirements.  If they are modified in any way, antenna or digital protocol, then, yes, the user must certify the module.



And why do the filed reports - all of them - claim compliance to Class C, industrial?



Dave - WØLEV



On Thu, Dec 16, 2021 at 10:07 PM Hare, Ed, W1RFI <w1rfi at arrl.org<mailto:w1rfi at arrl.org>> wrote:

David,

Solar systems are digital devices that are classified as unintentional emitters. If they are marketed into residential environments, they must meet Part 15 B emissions limits. The only unintentional emitters that require certification that would create an entry in the database you looked at are scanning receivers, radar detectors and access BPL devices.  Although they CAN certify if there is no US resident willing to take responsibility under a Suppliers Declaration of Conformity, the vast majority of unintentional emitters are not certificated, so there will be no information on the FCC page containing test data.  An SDoC is essentially self-policed.  The rules do not require that test data on devices authorized under an SDoC be provided to the FCC.

If they are using a certificated WiFi or Zigbee device that is used intact, its certification would suffice, so there would not be a need for a separate entry in the database, no more than you would need to certificate your station if you bought and installed a certificated Bluetooth microphone in it.

Ed, W1RFI





-----Original Message-----
From: RFI <rfi-bounces+w1rfi=arrl.org at contesting.com<mailto:arrl.org at contesting.com>> On Behalf Of David Eckhardt
Sent: Thursday, December 16, 2021 4:55 PM
To: Ken Bandy, KJ9B <ken.kj9b at gmail.com<mailto:ken.kj9b at gmail.com>>
Cc: Rfi List <rfi at contesting.com<mailto:rfi at contesting.com>>
Subject: Re: [RFI] Noise from Generac Solar controllers?

IN further poking around on the FCC OET site under Generac, I can't find a single report filed on anything except wireless hardware.  I could not locate any complete systems which would include the panels, optimizers, other electronic switching devices, and simulated house wiring.  There is no evidence in the reports of any test results being filed with the FCC for the entire system.  All the "Max Freq '' frequencies listed on the response pages for a general search on Generac on the FCC OET pages reflect only above roughly 700 MHz.  This tells me they are only filing for the intentional radiator, that being ZigBee or BlueTooth or some other protocol.  No complete *system test* is filed with FCC.  So, how can they claim compliance to even Part 15, Subpart C (Intentional radiator), Class C (industrial).  BTW:  Class C systems *do* require filing a test report with FCC.  There is none.

Dave - WØLEV

On Thu, Dec 16, 2021 at 5:06 AM Ken Bandy, KJ9B <ken.kj9b at gmail.com<mailto:ken.kj9b at gmail.com>> wrote:

> Hi all.  I am contemplating having a “PowerHome Solar” power system
> installed at my house, and am a little concerned about possible RF
> noise generation from the system.  This system uses a Generac
> controller.  Does anyone have any experience with a system using a
> Generac controller?  I know early inverters were often RF noisy, but
> I’m hoping that the later models have addressed noise generation.
>
> Any input is appreciated.
>
> 73,
> Ken, KJ9B
>
>
> _______________________________________________
> RFI mailing list
> RFI at contesting.com<mailto:RFI at contesting.com>
> http://lists.contesting.com/mailman/listinfo/rfi
>


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*Dave - WØLEV*
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Dave - WØLEV

Just Let Darwin Work




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Dave - WØLEV
Just Let Darwin Work