I have a mechanical equipment with electrical data 208V/1ph MCA-0.44 and MFS - 15. Can I use a 30A fusible disconnect connected to 20 Amp breaker in the panelboard. Is it code violation?
You can if you put 15A fuses in the disconnect.
NOTE: You will have to run #12 from panel to disconnect... unless this part of the circuit qualifies as a feeder tap under the rules of 240.21(B).
