[RE-wrenches] AFCI Faults, SMA Inverters, Solectria RSB's, & RF Signals

[Steven Lawrence]

Hi James,

Is the solectria combiner actually combining strings so you have one input
into the SMA inverter?  If so, did SMA approve arc fault detection at that
high current?  From what I understand, arc fault detection doesn't work on
strings greater than 20A.

In the solectria box, I'm assuming there is a contactor in there, correct?
Do you have coils of wire inside from the power supply to the contactor?  I
have seen instances where coiled wire was generated the noise itself.  Is
the wire from the power supply to the contactor shielded?


From: James Rudolph <jamesrudolph99 at gmail.com>
>
>
> Aloha Wrenches,
>
> I have a issue I would like to throw at the group.
>
> We have a SMA 24000TL-US with a Solectria Rapid Shut Down Combiner.
> The inverter keeps faulting the AFCI. We megged the strings,and checked all
> connections on all components. So we are confident that the issue is not
> related, or connected to all of that. We also swapped out the RSB.
>
> I really can't disclose where the building is located because its military,
> and most of their IT infrastructure happens to be in this building as well.
>
> I know from research, and tech support that this happens sometimes with RF
> signals,metal roofs,and communications antennas,etc.
>
> SMA is suggesting we could re-run the stings so that we mitigate the
> possibility that the strings are picking up this noise and triggering the
> AFCI, or get clearance to disable that feature on the inverter.
>
> Due to safety issues I'm sure the last option is not on the table.
>
> We can also place any given sting on the combiner and it will work fine
> with no faults up to four stings. Once we place more than four strings on
> the combiner the inverter will fault.
>
> Since we are still on the 2008 NEC in Hawaii this is our first run in with
> the Rapid Shut Downs too. Maybe somehow this is tied into the issue?
>
> Anyone have thoughts, or experience with this type of issue?
>
>
> Mahalo Nui,
>
>
> *James B. Rudolph*
>
> *Hawaii Unifed*
>
> *Director of  Energy*
>
> *ES Electrician # 10816*
>
> *NABCEP Certified PV Installer # 091209-155*
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