So the single line diagram distribution system question in the ncarb sample Mc question...
I do not remember seeing this in kaplan or ballast... googled for a good while, it seems single-line diagram is very common for HVAC systems and lighting systems.
And also found this link:
https://energycodeace.com/site/custom/p ... rcuits.htmSo at least for this MC question, diagram is very similar to:
Example 8-4
Combined lighting panel with subfeed to other lighting panel(s).
A larger first lighting panel (e.g. 400 amps) could subfeed three 100-amp panels, or 6 60-amp panels, and serve local branch circuits, too.
Can be used for lighting, HVAC, plug loads, or any other group of load types.
With my absolute no experience in this subject, and based on the link above, I'm interpreting:
C-panel-1 subfeeding D-panel-2 with 3 other panels, and C-panel-2 is also feeding another panel that serves a local branch circuit (the first symbol in D: one without the little line connecting the 2 dots on each side).
I'm not for sure this is the correct interpretation, but that's the best guess I got.