0 copper wire

--
That depends on the load's resistance, the ambient temperature, where
the wire is, and what it's covered with.

Do you mean that until I apply a load , there's no way to determine how much load it will handle?

--- No, what I mean is that unless you know what the load looks like, (and all the rest of it) it's going to be impossible to determine what the temperature rise in the cable is going to be and since the temperature rise will cause the resistance of the wire to rise, the amount of voltage it'll drop will increase, causing the voltage across the load to decreaase by the amount dropped in the wire.

For example, if you've got 700' of wire, (350' out and 350' back, say) since #0 AWG soft-drawn copper wire has a resistance of about 0.1 ohms per 1000 feet, that'll be a resistance of 0.07 ohms.

Now, if what you've got on the end of the cable wants to see

240V ±10%, then the most the cable can drop is 24V, and since I = E/R, the most current you can put through it will be 240V/0.07R ~ 3429 amps.

BUT... with 3429 amps flowing through the cable it'll be dissipating P = I*E = 3429A * 24V = 82,296 watts, so that's about 118 watts per foot. That cable's going to get HOT, and when it does its resistance is going to increase, which will further reduce the voltage across, and the current through, the load.

So, in order to be able to figure out what the wire's going to do, you need to know what the load looks like so you can pick an appropriate wire size. Also, you need to know where the cable's going to be and what it's covered with so you can determine how well it'll be able to get rid of the heat it's going to generate when current passes through it.

-- John Fields

Of course not, but that's not what was asked. Looking back at the original question:

"How much amperage you would get" appears to be a question asking how much current would actually be drawn, and this is impossible to say, as John noted. Assuming that "0 copper wire" refers to a copper wire of the 0 AWG size (and not a wire that contains "zero copper"!), the wire will very likely be capable of carrying the full 200 A that the service is capable of providing (actually, types T or TW at 0 AWG are only rated to 195A at normal ambients, but let's call it close enough for the moment), but who knows at this point how much will actually be drawn by the load?

If this IS a question about capacity, then 00 AWG or might be a better choice.

Bob M.

I don't have my NEC handbook handy, so I don't have your answer. But, make sure you get a handbook! The current carrying capacity of the cable is one thing, but what you should size your feeder breaker is another. Back when I was doing power distribution engineering, NEC guidelines stated that the feeder breaker trip should be set at 25% less than cable's current capacity. You must follow NEC guidelines to avoid fires.

BRW

/R,

er

Perhaps a nitpick, but I think you shifted from a 24 volt drop to dropping the entire 240 volts across the wire resistance. The amperage would come out to about 343 amps to get a 24 volt drop. Still, losing about 8200 watts in wire resistance is not something to ignore.

Practically speaking, 180 amps would be about the heaviest load you'd want to put on a 200 amp circuit, the loss would be (E=3DI*R) 180 * .07 = =3D

12.6 volts. This would have the wire dissapating 2268 watts over 700 feet or about 3.25 watts per foot. The wire would get warm, but should stay tolerable. There would also be a 6.3 volt difference between the neutral and "real" ground at the load, which might cause another set of problems.

For the original poster... The maximum amperage you could get after going through 700 feet of 0 AWG wire comming from a 200 amp service, is

200 amps. Any more would trip the circuit breaker (if pushed to the full 200 amps, you would get occasional trips anyway). And remember, as John pointed out, you have to figure the full round-trip travel the electricity takes. If you are really 700 feet from the service panel, you are running through 1400 feet of wire. Maybe the real question is how much voltage loss can your load stand, and how much do you want to pay to heat the wires. Going to a heavier wire size is a one-time expense. Losing energy in the wires costs you every time you pay your electricity bill.

--

     Tony Newman 
     Springfield, OR
     USA

Maybe I need to give more details and revise my question. What size wire would one need to run service to 10 homes in a distance of

700'??? Thanks, curt

--
Not a nitpick at all; a good catch. Thanks!

That's a completely different question! And I have to assume that when you speak of "200 A service" in this case, you mean that EACH HOME has a 200 A service, right? Splitting 200 A among

10 homes would be silly...

Given that, what you're REALLY asking is what you need to handle a total of 2000A max. split among 10 homes - but now the topology of the system becomes important. Are these 10 homes all strung out in a line (which means that the connection from the "main" supply to the first home has to be able to carry the full 2000 A, the next one 1800A, and so forth) or are they in a "star" configuration from one central point, or what? And do you really intend to run all ten off the same point, or will they be fed from a higher voltage (lower current) line and then have transformers, either for each individual connection or shared among some smaller groups within the 10-home total?

The real point here is that - if you have to ask this question, I think that you are already WAY over your head in terms of tackling this sort of project. Either that, or you're asking us to do your homework for you.

Bob M.

Sorry if I offended anyone, with my questions, I am trying to help people get electric to their homes in my area with a generator that outputs

200amps.We can get single 0 copper wire where we are. but the information that I need is NOT available to my knowledge. We are in a remote area of a different country from the USA. I just thought this was the place that I might get some info to help me. I will not bother you guys to "do my homework for me anymore". Thanks, curt

of

that

OK, with THAT information provided -

0 AWG copper wire is rated to at least 195 A for about any type in common use, so it has sufficient capacity. You wouldn't want to run all 10 homes "in series" anyway, as there would be excessive drop in the wire and - well, this just isn't the most efficient way to do this. The best thing to do would be to run individual lines from the generator to each home, but that is rarely practical. Most likely, your best bet would be to place the generator so that it is as centrally-located as possible, and then run branches from there to groups of homes or individual homes as needed - in short, try to spread the total load, and distance, as evenly as you can among several branches. If you have to have one or more homes signficantly farther away from the generator than others, try to minimize the load on that branch - in other words, you can trade the load in any given branch for the length of that branch, so that no one sees an excessive drop. Single branches to each home, if they're all going to be limited to 20A each, could do with wire a good deal smaller than 0 AWG, even if each branch were 700' long. 2 AWG would be acceptable for a run that long, for instance, and smaller sizes would be similarly acceptable for shorter distances (you could drop down to 4 AWG all around if the generator were centrally located within a 700' overall circle, such that no load were farther away than 350', and you'd still see

I am on an island that already has some grid electric, and have been promised to one day have it where I live. Until then, I can get by with the information you gave me.I really appreciate it! Thank again, curt

people

information