[RE-wrenches] AFCI problems with SMA RSB

[Drake]

The TL-22s are notorious for nuisance arc fault 
tripping. Is your array on a metal roof? Large 
metal roofs can amplify RF signals and cause tripping.

At 05:32 PM 9/29/2017, you wrote:

>Hi All, I’m wondering if anyone else is having 
>trouble with the SMA Rapid Shutdown Box. We have 
>an installation where an SMA 7700TL-US-22 
>(rebranded as SunPower) is fed by an array with 
>a Rapid Shutdown Box. Many, but not all, 
>mornings, the inverter would fail the AFCI 
>self-test on wakeup. When reset, it would 
>operate fine all day. There was never an actual 
>indication of an arc fault, just the self-test 
>failure. SunPower, in consultation with SMA, 
>decided to replace the inverter. Everything 
>worked normally for a couple of weeks, then the 
>problem resumed. Again, no arc-fault indication, 
>just the self-test failure and then full 
>operation the rest of the day after resetting. 
>We began to suspect the Rapid Shutdown Box, so 
>we bypassed it completely, and there were 
>absolutely no problems for several weeks. SMA 
>was then willing to replace the RSB, after which 
>everything worked fine for about a week, then 
>this morning the same issue. Again, self-test 
>failure, then when reset, it has to go through 
>another self-test, which it always passes and 
>then runs all day. Has anyone had problems with 
>the RSB, or, with AFCI in general? Based on this 
>experience, this is the second and last RSB 
>we’ve used, and have somewhat reluctantly gone 
>to all micro inverters to meet rapid shutdown. 
>Bruce Erickson Mendocino Solar Service PO Box 
>1252 Mendocino, CA 95460 707-937-1701 
>707-937-1741 fax bruce at mendocinosolar.com 
>Connecting Mendocino County to Solar Since 1994 
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