[RFI] Question Regarding Variations In Solar Panel RFI?

[Tony]

Jim:

Tom Simpson (Solar Edge Engineer) will be visiting the site sometime in 
the near future so I'm hoping he'll address the potential problems you 
mentioned.

The issues you describe may also explain why the suppression hasn't been 
very effective. The noise was 15db over S-9 prior to the suppression 
being installed and it's now S-9 plus a tad for a reduction of roughly 
10db.

This installation may require the methods used by Tony Brock-Fisher 
which includes chokes between the inverter and mains which is something 
Solar Edge frowns upon. Not sure if it's a cost or a code issue.

Thanks Jim.

Tony -K2MO





On 9/25/2020 6:49 PM, Jim Brown wrote:
> Tony,
>
> There are MANY variables and wiring errors and system layout errors 
> that can contribute to how much RFI is radiated. One issue that Teff 
> communicated to me was that the framing holding the panels was bonded 
> to ground on the other side of the building from the power entry. If 
> this is true, it creates a current loop that could be causing or 
> contributing to your problem.
>
> Wiring can be prevented from radiating by shielding, IF, AND ONLY IF, 
> the shielding is continuous. In the real world that I'm aware of, the 
> only shielded AC wiring is that which is enclosed in steel conduit, 
> that is continuously bonded together. That's quite rare in residences, 
> except in cities like Chicago, where the Electricians Union has it 
> written into the city's Electrical Code as a means of providing more 
> work to Electricians.
>
> Running twisted pair for power can prevent radiation from the 
> current-carrying conductors (phase and neutral), but won't help with 
> common mode RF current, which is nearly always on the green wire. And 
> the common mode current is there because of bonding failures, either 
> in the construction of the equipment itself, or in the installation, 
> or both.
>
> The wiring inside the home could be hot with RF as a result of wiring 
> errors at outlets, at panels (double-bonded neutral), even bonding at 
> equipment. At the home I bought in California, I found an outlet wired 
> with neutral and ground reversed, and I found outlets in the kitchen 
> of a "mother-in-law" garage apartment fed between phase and green 
> rather than phase and neutral. I also found no ground at all at the 
> service entrance -- it was bonded to a hose outlet that was fed by PVC 
> pipe!
>
> 73, Jim K9YC
>
> On 9/25/2020 3:22 PM, Tony wrote:
>> All:
>>
>> The reports I've read suggest that the strength of interference 
>> caused by solar panel systems can vary from one installation to the 
>> next EVEN when the distance to the source is similar. That variation 
>> could be attributed to radiating conductors tied to the system such 
>> as the house wiring.
>>
>> We found high levels of RFI on the A/C lines throughout my neighbors 
>> home and that's likely the case with all Solar Edge installations 
>> since there are no chokes between the mains and inverter.
>>
>> Given those facts, would a large home with long runs of un-shielded 
>> Romex produce higher levels of interference compared to a smaller 
>> home with shorter runs? Or does the resonance of the wiring play more 
>> of a role than length and number of runs?
>>
>> It's an oversimplification, but it seems logical to consider what's 
>> connected to system and not just the system itself.
>>
>> Tony -K2MO
>>
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