3phase fault current

[cooldesign]

what i wanna ask you, do we do arc flash for one phase equipment? i calculated all 3 phase faults, but i did not calculate one phase fault for single phase lines. do i have to calculate single phase faults currents for arc flash? because i saw in the IEEE1584 standart, it says arc flash analysis will be done for 3 phase analysis because it is greater than one phase fault current. what if for one phase equipment?

 

[tish53]

I am not up to speed on all the IEEE latest recommendations. That said, we calculate the Arc Flash on our three phase systems only. On our first arc flash study we modeled some 1 phase control and lighting circuits and all were very low.
I also believe that below 240 volts, arcs have a hard time sustaining themselves and the risk is much lower. All our 1phase loads are 240 /120 vac.