Yes, you can. If only four total are current-carrying, you do not have to derate the ampacity for the number of conductors: 310.15(B)(3)(a)(3)...Can I parallel 2 sets of say 4/0 4/0 2/0 cables and run them together in the same trench but come up into the equipment on both ends in seperate pipes? I will include a fourth conductor.
Adjustment factors shall not apply to underground
conductors entering or leaving an outdoor trench if those
conductors have physical protection in the form of rigid
metal conduit, intermediate metal conduit, rigid polyvinyl
chloride conduit (PVC), or reinforced thermosetting resin
conduit (RTRC) having a length not exceeding 3.05 m
(10 ft), and if the number of conductors does not exceed
four.
Yes, you can. If only four total are current-carrying, you do not have to derate the ampacity for the number of conductors: 310.15(B)(3)(a)(3)...
[Edit to add] Note the trench must be outdoors.
However, if by "include a fourth conductor", you mean an EGC... I believe a full-sized EGC per cable-pipe run is required.
How are you going to include a 4th conductor?
In general 300.3(B) requires the EGC to be in the same cable as the circuit conductors. 300.3(B)(3) may permit you to install it in the same trench with the power cable assuming a non-ferrous cable jacket.I was just going to lay it in the trench with the cable.
But what about where the cables emerge in conduit? Parallel cables, parallel conduits, parallel EGC's...???In general 300.3(B) requires the EGC to be in the same cable as the circuit conductors. 300.3(B)(3) may permit you to install it in the same trench with the power cable assuming a non-ferrous cable jacket.
Yes, if the cables leave the ditch via multiple raceways, multiple full sized EGCs will be required.But what about where the cables emerge in conduit? Parallel cables, parallel conduits, parallel EGC's...???