I have not looked at the posted block as I am running out but you seem to have quite a number of options that you would like but then want the Dyn Blk to be simple in design.
I think these two options are incongruous.
Mr. Shade, you would be exactly right about the two being incongruous. Then again, it would help if I properly read over the responses, and not try to deal in so much absolutes. You said infinitessimally small, which my mind forced me to equate to be 0 only. My bad! I then tweaked the line to be infinitessimally small, making it only 0.00001 units long. Then I recalibrated the Stretch action, and that was it!
Attached below is my new block. Mr. Shade, Ojuris, I thank you both.
That is again an impressive block. It proves there are more than one ways to solve problems (sorry, I'm a cat person, and don't like skinning cats ). The only thing about it for me, is that the default insertion mode of the block is for a two-pole breaker. Not bad, no, but my preference is to keep the default insert mode to single-pole breaker. Also, when a dynamic block is changed from its default insertion mode, AutoCAD makes it an anonymous block, with a secondary name. This adds kilobytes of data to the files that the blocks are used in, I have discovered. So, I draw blocks so their insertion mode is the most common mode of the block.
Again, well done with your block, and please feel no offense. I shall give your post a kudo for your effort, with which I am impressed.