[RE-wrenches] SMA Arc-Fault

[Dave Tedeyan]

This array is a ground mount, so not on a roof, and no radio towers nearby.

As for grounding, The array and the shed with the interconnection point are
in the same area.
There are a couple ground rods there, which everything on the AC side is
connected to,
including a #6 wire from each inverter. there is just a #10 ground coming
from the array to the inverters.
The house is a couple hundred feet away and has its own grounding electrode
system.

Jerry,
The inverters are new (replaced 2 months ago), but it is a good idea to
check firmware.
As for AC loads, nothing stands out as the types of things you mentioned,
although there
may be a well pump. They also do have a large water storage tank for
heating, but they
say that they have not needed to use it yet this year. Then there is also
the generator...

Thanks for your recommendations.
-Dave



*--*


*Dave Tedeyan*
*Project Engineer*

*Taitem Engineering, PC*
109 S. Albany Street, Ithaca, NY 14850
Voice: (607) 277-1118 x121
www.taitem.com

On Thu, Nov 10, 2016 at 9:51 PM, Jerry Shafer <jerrysgarage01 at gmail.com>
wrote:

> Dave.
> We have many TL-22 in the field and they will detect faults even when they
> are normal contactor faults, have you made sure the SW is the latest, last
> I checked it is 2.65.3R and it may have a patch in there, you can turn off
> the feature for testing only and see if you melt something down but if you
> do please be on site as a arc may happen. Do you have a well, AC system
> with contacts, welders, compressors, anything that has a dry contacts that
> brakes under load, this is another place I would look. Every time we have
> had a code out it was real weather from something normal or a wire issue.
> Not to brag but we have hundreds in the field from the 3's to the 24's and
> as much as I dread getting a call with this issue I can usually find the
> problem and it can be either AC or DC.
> Jerry
>
> On Thu, Nov 10, 2016 at 8:14 AM, Dave Tedeyan <dtedeyan at taitem.com> wrote:
>
>> Hi All,
>>
>> Maybe someone will have some ideas for why a couple inverters keep arc
>> faulting:
>>
>> -There are two SB7000TL-22 inverters, Sunpower branded.
>> -3 Strings of 7 SPR-327's to each inverter. Kept separate until the
>> inverter.
>> -Ground mount about 50' from the shed where the inverters are located
>> (indoors)
>> -Simple grid connected system, no batteries.
>> -There is a whole house generator co-located in the shed.
>> -We interconnect by using piercing taps on the line side of the generator
>> transfer switch
>> -There has been only one power outage there since the system was
>> installed in April, but the generator fires up weekly.
>>
>> -The arc faults have been happening on both inverters. Sometimes only one
>> at a time, sometimes both will go within a day of each other.
>> -The events have been approximately one a month, but sometimes more,
>> sometimes less.
>>
>> -We have already checked every single connection in the system twice, by
>> two different people.
>> -We have replaced the underground wires (and they looked just fine)
>> -We have replaced all home runs.
>> -We have replaced both inverters.
>> -Arc faults are still happening.
>> -Arc faults are not always on the same day/time of the week.
>>
>> I am wondering if this can be caused by the generator?
>> Has anyone run into a situation like this or something similar?
>>
>> Thanks for your help,
>> Dave
>>
>> *--*
>>
>>
>> *Dave Tedeyan*
>> *Project Engineer*
>>
>> *Taitem Engineering, PC*
>> 109 S. Albany Street, Ithaca, NY 14850
>> Voice: (607) 277-1118 x121
>> www.taitem.com
>>
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