Greg as far as my posts are concerned I think we have moved beyond the original question and moved on to a general discussion of breakers.

I do understand your point and most times I would agree.

However it sounds to me like even the manufacturer was confused when asked the question.

Quote
Spent the day getting info from manufacturer.
They didn't have anything in their instructions about derating of the transformer or using it at 100% load continuously so they sent me a letter stating that it was designed to run at 100%.
The engineer I spoke to said if you weren't able run it at 300 VA continuously on a 300 VA transformer they would have labeled it 240 VA Max.

I bet that is correct as far as the transformer, I still question if the breaker manufacturer would back that up. I doubt highly this engineer had anything to do with the design of the breaker.

But a letter is a letter so all is good. [Linked Image]

Bob

Bob Badger
Construction & Maintenance Electrician
Massachusetts