NEC gives max number of conductors for certain EMT conduit. For example, it’s 16x12AWG for a 3/4” conduit.
Now it turns out this is really not the limiting factor at all. It is de-rating.
Suppose I have 20A circuits (with 12AWG wiring) and I want to pack as many as possible into a conduit. With de-rating I am practically limited to 9 current carrying conductors, or 4 20A branch circuits. I can’t even increase this by using a very big, say 2” EMT.
Is this true?
The only option I see is running multiple conduits in parallel.
Alternatively I could use 10AWG which is nominally rated up to 30A and put up to 20 into an EMT which would de-rate to 20A. This is effectively 10x20A branch circuits. I would need at least 1-1/4” EMT to satisfy “static” fill requirements.
Do I have any other options? How is this done in practice?