( 0.03 \times 230 = 6.9 \text V )
[ I = \fracPV ]
[ V_d = 7.3 \times 21.7 \times 50 / 1000 = 7.92 \text V ] Still slightly over 6.9 V → try 10 mm² (~4.4 mV/A/m): [ V_d = 4.4 \times 21.7 \times 50 / 1000 = 4.77 \text V \ \text(OK) ] Step 4 – Consider Short-Circuit Temperature Rise For critical installations, ensure the cable can withstand a short circuit until protection operates: how calculate cable size