TomH in PA
Well-known Member
When I wired my shop it crossed my mind that I could save a few feet of wire by doing the following:
I have a 220 volt outlet near the sub-panel. Also, running through metal conduit from the sub-panel to a junction box near the ceiling, the left side of the shop has a black and a white wire, right side has a red and white wire (red carrying the secondary live). It occurred to me that a single white (neutral) running from the sub-panel to the junction box and tied to both white wires inside the box would be enough, since it could never carry more amperage then either the left or right side of the shop was using; if I ever had tools running on both sides of the shop the hots would be out of phase and (in my theory) would actually reduce the load in the single white returning from the junction box to the sub-panel.
I didn't actually do it, ended up running two white wires down to the sub-panel. But I wonder how/why the idea was dumb. I suppose the biggest bad would be if someone were to move the red wire in the sub-panel over to the primary hot feed and potentially double the amperage on the single white.
I have a 220 volt outlet near the sub-panel. Also, running through metal conduit from the sub-panel to a junction box near the ceiling, the left side of the shop has a black and a white wire, right side has a red and white wire (red carrying the secondary live). It occurred to me that a single white (neutral) running from the sub-panel to the junction box and tied to both white wires inside the box would be enough, since it could never carry more amperage then either the left or right side of the shop was using; if I ever had tools running on both sides of the shop the hots would be out of phase and (in my theory) would actually reduce the load in the single white returning from the junction box to the sub-panel.
I didn't actually do it, ended up running two white wires down to the sub-panel. But I wonder how/why the idea was dumb. I suppose the biggest bad would be if someone were to move the red wire in the sub-panel over to the primary hot feed and potentially double the amperage on the single white.