A 20-amp circuit allows you to run a 10 gauge wire up to 85 feet. When used on a 15-amp circuit, this type of wire may stretch up to 115 feet. Because 12 gauge wire is also 10 gauge wrapped around another core, it can handle the same amount of current as 10 gauge wire.
The actual distance that a cable will carry current depends on how long it is and what kind of insulation it has. For example, solid copper wires are the best choice for longer runs because they don't break down like cable TV wiring does when it's exposed to moisture in outdoor installations. Coaxial cable, which contains both solid metal cores and plastic insulation, is recommended for shorter distances because it's more flexible. You can also use aluminum wire in place of solid copper; it's about half as expensive as regular copper wire.
As long as you use the right type of cable for the job, you can run 10 gauge wire for 20 amps safely. But if you plan to add circuits later or if you're just asking yourself "how far can I run this?" then you should invest in some proper cable. There are several different types of cable available on the market, so check the labeling to see what type you need before you start wiring up your home.
How far can 12 gauge wire be run on a 20-amp circuit? Approximately 400 feet. After that, voltage loss is a concern, and either the gauge or the voltage must be raised. The usual rule is that the number of amps required for your wiring job should not be more than 10 percent of the circuit's capacity.
The best way to be sure you have enough power for your needs is by checking with a power meter. If you're running a single circuit, most power meters will show you the total amount of electricity being used by displaying the wattage read from the meter. To determine how much power your household appliances are using, multiply their peak watts by the hours they are plugged in each day. For example, if one appliance uses 15 watts continuously and another uses 25 watts for one hour every night when the lights are off, then their combined use adds up to 40 watts times 8 hours a day plus 37 watts times 1 hour a night = 290 watts. At 110 volts, this would be 2.9 amps; at 220 volts, it would be 5.8 amps.
If you plan to have more than one electrical device plugged in at any given time, such as a lamp and radio, or a vacuum cleaner and hair dryer, add their peak values together. Then divide the result by two to find the average current consumption per device.
Using the table, you may run an 18-gauge wire up to 451 feet if you are using a gadget that requires up to 417 mA of electricity. If your appliance requires more current, you will need to either replace the wire with one that carries more than 18 amps or connect multiple wires together.
Use 2-gauge cable for amp loads of 150 to 200 amps and wire lengths of 25 feet; 4-gauge wiring is suitable for amp loads of 150 to 200 amps and wire lengths of 15 to 20 feet, while 100 amps at 25 feet is recommended. Some 6-gauge wire is adequate for 100 amp draws and distances of 15 to 20 feet. For 400 amps or more, use 6-gauge wire in conduit or armored cable.
The current flowing through the wire generates heat, which must be taken away otherwise it will cause it to melt or burn. The faster the circuit carries current, the more heat it will produce. So for a given load, a high-current circuit requires thicker wire than a low-current one. But actually getting enough wire to make a difference is not so easy - the main problem being space! You can get by with fairly thin wire if you're working with a lot of current but trying to fit two or three small circuits into a small area then four or five inches would be far too little.
The best way to ensure you have enough wire is to calculate how much current your amplifier needs and then select a size wire that's large enough to handle it safely. For example, if you need 250-amp capacity, then you should use 4-gauge copper wire because it'll carry this load for about 20 feet without breaking down. If your load is less than 250 amps then you'd use 2-gauge or 3-gauge wire instead.
You can run 14 AWG for hundreds of feet if you have a very tiny load. For example, 14 AWG copper THHN 90C in conduit with a 3% voltage loss would offer approximately 600 feet at one amp but only around 50 feet at fifteen amps. How many amps can a 12 gauge wire handle? The same rule applies - depending on load, it can take 12 AWG wire for hundreds of feet.
As long as your load is less than 15 amps, 14 AWG wire can be used for a long distance. But if the load exceeds 15 amps, then 8 AWG wire should be used instead.
The current rating of wire is usually printed on the package or wrapping. For example, if you look on the back of the box, you will see "Current limited to 20 amperes" or "Current capacity: 20 ampeers". This means that the wire can carry up to 20 amperes before it gets too hot and needs to be replaced. If the label says "Current limit: 30 amperes", then the wire can safely carry 30 amperes without getting too hot.
It is important to remember that wire resistance increases as current flows through it. So if you use 14 AWG wire and your load is 40 amps, then more than half of the wires thickness will be melted away after just 10 feet! 80% of the original width would remain after 20 feet.
At 100 feet, a 12 gauge wire can normally carry 15 amps. They recommend a 6-gauge for your 160 feet. That's half the size of a 14 AWG wire and you'll need three of them instead.
12 gauge is most commonly used for exterior wiring because it's large enough to be visible after being covered with insulation and paint. If you have to remove the skin from the building to repair or replace any wiring, then you should use a larger size wire like 14 or 16.
The current in wires gets heated when there's a lot of demand for electricity, like when several lights are on or an air conditioner runs. This heat can cause damage to the wiring over time. In fact, that's why all home electrical systems include overload protection in some form. Overloaded circuits will shut off the power to those lines to prevent overheating and possible fire.
Exterior wiring needs to be able to handle at least 10 amperes continuous current without shutting down. This means that if all your lights are on, it's safe for your circuit breaker to go up to its maximum capacity. It won't stay there for long though; the current will eventually drop back down below 10 amperes once all the lights are turned off.