Circuit 1: 240V 10AWG 30A 135’

voltage drop calculated is ~10V, 4.2%

Circuit 2: 120V 10AWG 20A 135’

voltage drop ~ 7V, 5.6%, 113V

the 240V is to run an electric heater of 5,000W, = ~21A

The 120V is for minor loads, but periodic high loads, e.g. miter saw (short bursts) plus 2 vacuums (left on).

the present circuit is has too many outlets 120v 20A 12AWG ~150’. It very rarely trips. The voltage only drops from 120 to 118 with minimal load.

The question(s) are

1) Are the wire sizes calculated above based on full amperage all the time?

Is the calculation for circuit 2 to supply close to 20A and 113 V all the time?

2) is it reasonable to expect the 240V circuit to safely draw the calculated 21A nearly full time ?

I’m trying to not use any thicker wire than necessary ($$$)

thank you!