Can I have one 240V 30A circuit with 3x8AWG (clothes dryer) and two 20A circuits (washer and bathroom circuit, 120V with neutral each) together in one 3/4” flex SMC?
I believe so but I haven’t found a definite answer. In terms of fill it should be definitely ok (3x8AWG+4x12AWG is 28.39% fill for 3/4” flex FMC.
In terms of de-rating, if all conductors were 8AWG I could have up to 6 of them while maintaining 40A ampacity. However, I have only 3 8AWG and 4 12AWG. If I had only 12AWG, I could have 9 of them. I don’t know how to do it mixed but given that only 3 are 40A I feel it should be ok.
Background: My dryer has a dedicated 240V 30A circuit over 3x8AWG within said 3/4” flex FMC.
The washer and the bathroom are currently on a random 15A circuit with plugs and stuff in other rooms.
Per code, washer should be dedicated circuit as should be the bathroom (latter should be 20A). Since all of them are close it would be perfect if I could pull two dedicated 20A circuits and reuse the existing dryer conduit.
EDIT: Dryer circuit is 30A, not 40A.