I'm planning to wire a 240v 1000w metal halide bulb. It will be plugged into a digital timer via a NEMA 6-15 plug. The NEMA plug has hot, neutral, and ground. The ballast has one hot tap. This is probably a stupid question, but:
is it OK to run 240v across one hot lead (black only) from the NEMA plug to the ballast tap? I'm going to use 12 AWG wire, rated for 600v. Common sense tells me since it's rated for 600v, then this would be fine.
Everything I'm reading online mentions running 2x 120v wires, one with red and one with black. This is confusing. It seems weird for my application considering the NEMA plug's single hot terminal can handle "up to 10 AWG." 2x 12AWG wires wouldn't fit. Same goes for the ballast tap.
I just want to confirm because I want to do this properly. Thanks
If it helps any, this is a european manufactured ballast (Tridonic). I'm told that the neutral (comm) of the supply is to connect to the outside of the lamp socket, as well as the neutral tap on the ignitor. The capacitor is supposed to be wired parallel, 240v on one tap and neutral on the other.
Do I just not understand the flow of electricity?
Is it possible that what you're trying to say is that there is no GROUND on the NEMA plug, because GROUND in this case, is the neutral (white wire)? That would make a hell of a lot more sense.
Much advice has been given to you since you posted the above.
However, it appears that you do not understand the distribution of AC energy to North American premises and how it differs from the distribution of AC energy in Europe, and most of the remainder of the world.
You stated "The NEMA (6-15) plug has hot, neutral, and ground."
NO. It does NOT.
It has two (flat - horizontal) Line terminals (L1 and L2) and a (round) Earth terminal.
You also asked "Is it possible that what you're trying to say is that there is no GROUND on the NEMA plug, because GROUND in this case, is the neutral (white wire)?
NO. What is trying to be said is that there is no "NEUTRAL" on the (three pin) NEMA 6-15 plug (because it is unnecessary), but there is an Earth" connection - because it will be necessary (unless the equipment concerned is "Double Insulated")
You also stated "Everything I'm reading online mentions running 2x 120v wires, one with red and one with black." to which I would add, "plus an Earth."
It seems to come as a surprise to you that (just like Europe, and most of the remainder of the world) North America has a 240 V (230 V) single phase distribution system to domestic premises.
The significant difference is that (in Europe etc.) one side of the 240 V AC single phase transformer supplying the premises is connected to Earth (as a Neutral) BUT, in North America a "centre tap" of the transformer supplying the premises is connected to Earth (as a Neutral.)
The result of this is that European (etc.) premises are "fed" via only TWO wires (Line and Neutral). with 240/230 V AC available between Line and Neutral.
However, in North America, premises are fed with THREE wires Line 1, Line 2 and Neutral. Because the transformer is "centre tapped", each of these two "Lines" is at 120 V AC with respected to the "Earthed" Neutral.
(Because these 2 120 V AC supplies are 180 degrees "out-of-phase", 240 V AC is "available" between them.)
Most (low wattage/low current) devices in North America can operate quite happily on 120 V. However, at 120 V, a 15 A circuit cannot supply more than 1800 W and a 20 A circuit cannot supply more than 2400 W.
To obtain up to double this "Wattage" via conductors of similar size it is necessary to double the voltage, by connecting across Line 1 and Line 2, where a potential difference of 240 V AC is available.
Note that the "outside" of your "Edison Screw" lamp socket will be connected to one of the 120 V AC (with respect to Earth) "Line" supplies. While it should be externally insulated, it represents a possible 120 V AC "danger".
As a bit of "History", (largely because of the "War of the Currents" [which should be called the "War of the Voltages] between Edison and Westinghouse) the "powers that be" in North America (read USA) became convinced that 240 V AC (of which the "peak" voltage is 340 V) was more "dangerous" than 120 V AC (of which the "peak" voltage is 170 V). So the dual 120 V AC (with respect to Earth) supplies became the "norm" in North America.
(Edison would have preferred the use of his nice "safe" 110 V DC.)
Perhaps you should read https://en.wikipedia.org/wiki/War_of_Currents