Main panels - no label. Can you determine size?

[ryangittens]

Is there any way to determine the size of a panel if there are no labels or the labels came off?

Usually there is a marking on the main breaker but this one doesn't appear to have. The panel itself appears to be a meter main Siemens but there is no marking. From what I can tell there is no reliable way besides assuming the ampacity from the feed through conductor size.

 

[jaggedben]

How to determine panel bus rating when there is no label?

I see this a lot in plan sets, they specify a bus rating when there is no label anywhere on the panel. Since I'm working in PV the bus rating is part of a calculation that determines what size backfeed breaker can be installed. I often wonder if in the absence of a label the bus rating becomes...

forums.mikeholt.com

I don't recall being unable to get a rating off a main breaker.