I'm stupid please help Watts, amps, volts.

[Bmoney]

Watts=Volts x amps
Ohms= resistance aka heat/low amps
Wire gauge needs to be able to handle the amps and heat before melting/shorting
Metal matters less resistance/thicker wire/melting temp matters.

Blah Blah Blah basics
Standard  North America power is 120v cool. 
My question is how much does voltage matter in wire gauge?
standard 20 amp circuits use 12 guage wire for 120v. About 2400watts. 
Can that same wire handle 12v at 200amps?
or 1200v at 2 amps?

Right? Wrong? 
What I know (because home voltage is pretty standard) wire gauge is more tied to amps than volts. 
That why flash bulb can have massive volts on thin wires. right?

[mahyar]

3 minutes ago, Bmoney said:

Can that same wire handle 12v at 200amps?

nope

3 minutes ago, Bmoney said:

or 1200v at 2 amps?

maybe

[WhitetailAni]

North American power is 240V.

We just do it a weird way where we split it into 2 120V circuits.

That's why 240V circuit breakers span 2 slots.

And yes, you can have megavolts across superthin wires. That's how we transmit power across long distances.

And yes, bigger (or smaller if you look at the number value) wire gauge (I'm pretty sure) is dependent on amperage, not voltage.

 

[SteveiJobs]

Current matters for the size of the wire (larger wire can carry more current).

 

Voltage matters when considering jacketing material and thickness since it's a dielectric. Thicker material protects against higher potentials. 

 

I've seen 1000 KCmil substation cable that is about the diameter of your forearm and has jacketing an inch in thickness. That usually carries 34,500 volts or more.

[dfsgsfa]

high V reduces energy loss due to resistance , when compared to low V

v =i x r

[AbydosOne]

27 minutes ago, Bmoney said:

Can that same wire handle 12v at 200amps?
or 1200v at 2 amps?

The ability for a wire to carry current is limited by its internal resistance: higher resistance = more power lost in transmission; bigger the wire, the less the resistance.

 

The formula for dissipated power vs current is P = I² * R. As you increase current through the wire, the power dissipated goes up by the square. The higher the voltage, though, the less the voltage drop will be (relatively speaking), and the more power per amp you can put in the wire (at the receiving end).

 

The rated voltage has little to do with a wire's metallic makeup and more to do with the insulation around it (it's easier to insulate 12V than 12KV). From the wire's perspective, amps are amps.

[WhitetailAni]

Go here.

American magic.

 

[SteveiJobs]

Should also clarify that what it really comes down to is heat. If wire has zero resistance, there's no problem and you can pass as much current as you want, but nothing has zero resistance.

 

Even a tiny resistance can translate to a ton of heat at high amps which breaks down the physical structure of the wire. 

[Hackentosher]

Quote

My question is how much does voltage matter in wire gauge?

standard 20 amp circuits use 12 guage wire for 120v. About 2400watts. 

Well yes, but also no. The resistance of a conductor is given by the legnth of said conductor multiplied by the restively of the material divided by the cross sectional area of the conductor. So the lowest value resistor has a short length and a large cross sectional area (gauge). The voltage determines how much current can flow through a given conductor. If you have a 1 ohm wire and throw 120v down it's throat, by ohm's law the current through that wire will be 120 amps. The wire will try to pull that, but there may be other factors in the system that prevent this from happening. Ohm's law and the power equation can be rearranged into P=V^2/R, so that 1 ohm wire would dissipate 14,400W across it if given the opportunity. That's the equivalent of almost 10 space heaters! There are other parts of a circuit that limit the current, and thus power dissipated across wires and other conductors otherwise shit wouldn't work. Generally, you want your power wires to be large gauge so they are low resistance so that they don't drop very much voltage across them when delivering power to your circuit.

Quote

Can that same wire handle 12v at 200amps?

Probably not, 2400W is a shit load of power, especially to dissipate in a wire. That heat probably can't go any where so it'll just raise the temperature of the wire higher and higher until it either melts, or auto-ignites something around it.

Quote

or 1200v at 2 amps?

Here you run into a different problem. Wire insulation has a property known as a dielectric strength, aka maximum electric field.  A definition of how large of a voltage potential can be placed through a length of the material before the potential is too high and the material starts conducting. This is why you see some lengths of wire specify a voltage rating, or why electrical tape is only good to 600v. You would need a wire that has good enough insulation to withstand that much potential.