Siemens - Suitable for back feed or not suitable for back feed - that is the question!!

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wytelytning

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This one has brought conversation amongst quite a few of us but have not been able to verify the truth in it....

Are Siemens Type QP Circuit Breakers suitable for PV back feed?

The general response is, "why would they not be?" We have not been able to find any documentation that says one way or another - If they are not - then we would have to do a countless number of Main Service Upgrades just to change manufacturers...

Let the conversation begin
 
wytelytning said:
This one has brought conversation amongst quite a few of us but have not been able to verify the truth in it....

Are Siemens Type QP Circuit Breakers suitable for PV back feed?

The general response is, "why would they not be?" We have not been able to find any documentation that says one way or another - If they are not - then we would have to do a countless number of Main Service Upgrades just to change manufacturers...

Let the conversation begin
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Unless the terminals are specifically stamped LINE and LOAD on the breakers themselves, you can backfeed them.
 
During the UL certification testing (UL 489) the normal testing procedure tests for operation in the reverse direction (7.1.1.25). If the CB fails or the manufacture opts out of that part of the test then they must mark the CB with Line and Load on the terminals. If the CB is not marked then it is listed for backfeed. There is no separate test or listing for a backfeed capable CB.
Now this section starts with, "Except for single-pole circuit breakers tested singly" and I have to admit I am not sure what that means. Does it mean that single pole CBs tested singly are not tested for reverse operation even if not marked Line and Load or does it mean that even if the single pole CB is marked Line and Load it is tested for reverse operation? I'm leaning toward the former which means to me that single pole CBs tested singly are not tested for reverse operation and therefore not listed for backfeed, even if the terminals are unmarked.
 
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pv_n00b said:
During the UL certification testing (UL 489) the normal testing procedure tests for operation in the reverse direction (7.1.1.25). If the CB fails or the manufacture opts out of that part of the test then they must mark the CB with Line and Load on the terminals. If the CB is not marked then it is listed for backfeed. There is no separate test or listing for a backfeed capable CB.
Now this section starts with, "Except for single-pole circuit breakers tested singly" and I have to admit I am not sure what that means. Does it mean that single pole CBs tested singly are not tested for reverse operation even if not marked Line and Load or does it mean that even if the single pole CB is marked Line and Load it is tested for reverse operation? I'm leaning toward the former which means to me that single pole CBs tested singly are not tested for reverse operation and therefore not listed for backfeed, even if the terminals are unmarked.
Click to expand...
Thank you for the verification
 
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