electrical wire size chart

Electrical Wire Sizing Chart

Wire Size	Area mm2	COPPER	COPPER
AWG	Area mm2	VDI	Ampacity
0000	107	99	260
000	85.0	78	225
00	67.4	62	195

May 3 2022

Full Answer

How to calculate the electrical wire size?

– The calculator uses the following formulas for calculating wire size, which are based on Ohm’s Law. For single-phase circuits: Wire Circular Mils = (Conductor Resistivity)(2)(Amps)(One Way Distance in Feet) Allowable Voltage Drop For 3-phase circuits: Wire Circular Mils =

What are the different sizes of electrical wire?

Wire size calculation formulas

• Explanation of the components
• Derivation of the required values. Nominal current \mathbf {I} and efficiency \mathbf {\cos \varphi} can be found in the manual or on the type plate of the machine.
• Wire size calculator tool. The online calculator helps you to determine the wire size for the desired parameters. ...

What size electrical wire should I run?

• It could break, rip, or tear.
• It’s a hazard to others in the yard.
• It’s inconvenient if you want to plug in more than one device.
• You can’t light your shed and use a tool at the same time.

Where do you find wire size vs. amps chart?

• Understand how much current you need to draw for your tool or appliance
• Properly size the wire gauge to the length and current draw required
• Keep your cables as short as possible for higher current tools
• Unroll extension cords fully so they aren’t coiled during use

How do I know what size electrical wire to use?

Look at the insulation on the cable. Search for text written on the insulation. ... Cut the wire with your wire cutters. The cut should be perpendicular to the run of the wire.Measure the diameter of the cross-section in inches. ... Divide the diameter of the wire by .

How big should my wire be?

RULES OF THUMB. Many techs will repeat these rules of thumb and rely on them in all circumstances: “Twelve-gauge wire is good for 20 amps, 10-gauge wire is good for 30 amps, 8-gauge is good for 40 amps, and 6-gauge is good for 55 amps,” and “The circuit breaker or fuse is always sized to protect the conductor [wire].

What wire is needed for 220v 30 amp?

In most cases, you will need an #8 AWG wire for a 30 amp 240V circuit. The key for 30 amp wire sizing is to account for 2 NEC codes, namely: NEC 220-2 Code. This requires that a conduit wire's maximum load (30 amps) represents 80% of ampacity of that wire.

How many amps can 2 AWG wire handle?

115 ampsHow many amps can a 2 gauge wire handle? Well, at standard temperature of 75°C, the 2 gauge wire has a 115 amps ampacity. That means that any 2 gauge copper wire can, at that temperature, handle up to 115 amps safely.

How far can you run a 20 amp circuit?

You can run a 10 gauge wire up to 85 feet on a 20 amp circuit. If you opt to use this type of wire on a 15 amp circuit, it can run up to 115 feet. After these distances, the circuit will go over the recommended 3% voltage drop. You can run a 12 gauge wire up to 70 feet on a 15 amp circuit.

What wire is used for outlets?

What Size Electrical Wire Should I Use When Wiring an Electrical Outlet (Receptacle)? For a 15-Amp circuit use #14 copper wire (or #12 copper-clad aluminum wire). The fuse or circuit breaker feeding this circuit is rated for 15 amps. For a 20-Amp circuit use #12 copper wire (or #10 copper-clad aluminum wire).

Can you run 12 gauge wire on a 30 amp breaker?

You should not use a 30-amp circuit breaker on a 12-gauge wire. The circuit breaker installed on a circuit is of a specific size to protect a certain wire gauge. A larger breaker on a thinner wire will allow more current over the wire before tripping.

How many receptacles can be on a 20 amp circuit?

The answer to the question how many outlets on a 20 amp circuit is ten outlets. Always comply with the 80% circuit and breaker load rule, allowing a maximum load of 1.5 amps per receptacle. Remember that your circuit, wire sizes, and outlets must be compatible to avoid overheating and electrical hazards.

How many receptacles can be on a 30 amp circuit?

The NEC states that you can only have 30-amp receptacles on a 30-amp circuit.

What is 3 wire used for?

Three-conductor wire has two hots — black and red — and a white neutral. Though normally used for three-way switching, three-conductor wire is commonly used for duplex receptacle wiring as well. For a partially switched receptacle, for example, you would break off the tab on the brass side of the receptacle.

How many amps is #3 wire good for?

100Wire Size and Amp RatingsWire Size75°C (167°F)AWG(mm²)Copper4(21.2)853(26.7)1002(33.6)11517 more rows

What does AWG stand for?

American Wire GaugeAmerican Wire Gauge (AWG) is the standard way to denote wire size in North America. In AWG, the larger the number, the smaller the wire diameter and thickness. The largest standard size is 0000 AWG, and 40 AWG is the smallest standard size.

How many mm is a n gauge wire?

The n gauge wire diameter d n in millimeters (mm) is equal to 0.127mm times 92 raised to the power of 36 minus gauge number n, divided by 39:

How many times is the resistance of a n gauge wire?

The n gauge wire resistance R in ohms per kilometer (Ω/km) is equal to 1000000000 times the wire's resistivity ρ in ohm-meters (Ω·m) divided by the cross sectional area An in square millimeters (mm2):

How to find the cross sercional area of a n gauge wire?

The n gauge wire's cross sercional area A n in square millimeters (mm 2 ) is equal to pi divided by 4 times the square wire diameter d in millimeters (mm):

When does a circuit need a larger wire size?

A more engineering approach is cited at the Mike Holt's electrical forum where a reader says as an engineer he calculates the voltage drop (and thus the need for a larger wire size) when the run length of the circuit exceeds voltage rating of the circuit.

What is the NEC code for electrical wire?

The U.S. National Electrical Code NEC 240-3 requires that the electrical branch circuit, feeder wire, and electrical service conductors shall be protected against overcurrent in accordance with their ampacity ratings as specified in NEC Table 310-16. 4.

What is the maximum voltage drop for residential wiring?

Typically the maximum allowed voltage drop in residential wiring is 3%. For motor circuits and other applications less voltage drop may be acceptable, and you may need to consider both the starting voltage drop and the running voltage drop allowed.

When did the wiring size vs ampacity ratings change?

Since some readers request historical data on electrical code provisions we note that the data in this article has been excerpted / adapted from the U.S. National Electrical Code. The locations of wiring size vs ampacity ratings changed in the 2011 NEC and again in the 2014 NEC.

How to find amps in a circuit?

To determine amps, add up the wattage of all electrical devices that will be on the circuit and divide this total by the voltage of the circuit, 110 or 220.

What is the ambient temperature of a cable?

National Electrical Code for 2002 for ampacities of not more than three current-carrying conductors in raceway, cable, or earth, based on an ambient temperature of 86°F / 30°C

What is the power factor of a residential circuit?

For typical residential electrical circuits with resistive loads (such as lighting, not motor loads) using a power factor of 1 and assuming a negligible line reactance, above on this page is an example table (see warning and citations throughout this article and at REFERENCES ).

What is electrical wiring?

Electrical wiring is installed to provide a wide range of power options in your home. It is used for lighting, receptacles to power things like TV's, stereos, curling irons, and hair dryers. The wiring also feeds a variety of appliances, both big and small, throughout the home.

What gauge is wire gauge?

A wire is sized by the American Wire Gauge (AWG) system. Your installation of conductors will depend on a few factors. The gauge of the wire, wire capacity, and what the wire will feed should all be considered.

What is triplex wire?

Usually, triplex aluminum wire was used to run from the power pole to the service entrance weather head feeding your electrical disconnect, that eventually powers your electrical panel in your home.

How long is wire in a spool?

The electrical wire can come in rolls or on spools. Lengths of wire vary from standard cuts of 50, 100, 250, 500 and 1,000 feet, but can be special ordered for specific lengths.

What appliances have their own circuit?

These separate circuits are specific to appliances that must remain running at all times, like freezers, refrigerators, ranges, electric water heaters, and clothes dryers.

What is direct burial cable?

Direct burial cable is a special type cable that is designed to be run in a trench underground without the use of conduit to surround it. The electrical wires are encased in a thermoplastic sheath that seals out moisture and protects the wires within.

Can copper wire handle more amperage than aluminum wire?

Although some wires look the same and even look to be the same size, it doesn't mean that they can handle the amperage. For instance, copper wire can handle more than aluminum wire and should always be your choice of wiring to install in your home.

How many feet per pound of wire?

Feet per pound refers to the number of feet of wire needed to reach one pound in weight. (e.g., AWG 4 wire requires 7.918 feet, while AWG 40 requires 34.364 feet.) Resistance (ohms per 1000 feet). A wire’s electrical resistance depends on its length and thickness. Longer wires provide greater resistance than shorter wires.

How many amps can a wire handle?

American Wire Gauge standards range from 0000 (which can handle up to 302 amps) to 40 (which can handle up to 0.0137 amps). Most household and commercial wiring demands range from 2 (95 amp maximum) or 3 (85 amp maximum) to 14 (15 amp maximum). In the table below, we outline all of the AWG cable sizes and their unique properties.

What is the difference between AWG 40 and AWG 4 wire?

(e.g., At 25° C, AWG 4 wire has a resistance of .2485Ω for 1000 feet, while AWG 40 wire has a resistance of 1079Ω for 1000 feet.) Current capacity (amps).

What is AWG wire gauge?

American Wire Gauge (AWG) is a standard method of measuring and identifying cable thickness developed in the United States for electrically conductive wire. It is suitable for specifying gauges for round and solid conductive wires made from non-ferrous material.

Why do electrical wires need to be thicker?

For example, electrical circuits with higher amperage ratings require thicker wires to accommodate the load without experiencing excessive heat buildup. Using wires that are too thin for the specified circuit amperage can result in wire failure or ignition.

What is gauge wire?

What Are Wire Gauges? The gauge of a wire refers to its thickness. Each gauge is represented by a number, with smaller numbers representing thicker wire gauges and higher numbers signifying thinner wires.

What is craft wire?

For example, craft wire is thin to support bending, forming, and twisting into jewelry and other craftwork. In the following guide, we provide an overview of what wire gauges are, why they’re important, key considerations, and standard sizes available to help industry professionals select the right wire gauge for their application.

How to calculate AWG?

AWG: In the American Wire Gauge (AWG) system, wire size diameters can be calculated by applying the formula D (AWG)=.005·92 ( (36-AWG)/39) inch. For the 00, 000, 0000 etc. gauges you use -1, -2, -3, which makes more sense mathematically than "double nought." This means that in American wire gage every 6 gauge decrease gives a doubling of the wire diameter, and every 3 gauge decrease doubles the wire cross sectional area. Similar to dB in signal and power levels. An approximate but accurate enough form of this formula contributed by Mario Rodriguez is D = .460 * (57/64) (awg +3) or D = .460 * (0.890625) (awg +3).

What is ampacity in electrical?

Definition: ampacity is the current carrying capability of a wire. In other words, how many amps can it transmit? The following chart is a guideline of ampacity or copper wire current carrying capacity following the Handbook of Electronic Tables and Formulas for American Wire Gauge. As you might guess, the rated ampacities are just a rule of thumb. In careful engineering the voltage drop, insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account. The Maximum Amps for Power Transmission uses the 700 circular mils per amp rule, which is very very conservative. The Maximum Amps for Chassis Wiring is also a conservative rating, but is meant for wiring in air, and not in a bundle. For short lengths of wire, such as is used in battery packs you should trade off the resistance and load with size, weight, and flexibility. NOTE: For installations that need to conform to the National Electrical Code, you must use their guidelines. Contact your local electrician to find out what is legal!

Does AWG go up or down?

Note that in AWG the diameter goes up as the gauge goes down , but for metric gauges it is the opposite. Probably because of this confusion, most of the time metric sized wire is specified in millimeters rather than metric gauges.

How to determine the proper size of a circuit?

The proper circuit size, as indicated by amperage, is determined by several factors, including the planned load on the circuit, the number of outlets or light fixtures, and the length of the circuit. Once the proper amperage is determined, though, it is critical, that the wire gauge used in the circuit is appropriate for the amperage ...

What gauge wire is used for a switch?

But solid wire is usually easier to secure under screw terminals, such as those found on standard switches and receptacles. In standard usage, though, the wire conductors in conduit or NM cable for household wiring will be 14-, 12- or 10-gauge wire that is a solid copper conductor.

Why is it important to make wires larger?

The higher the amperage rating of the circuit, the larger the wires need to be in order to avoid excess heat that can melt wires ...

Why is aluminum wire used in homes?

Aluminum wiring was once widely used, but because it was found that aluminum had a greater expansion profile under load, it often loosened wire connections and sometimes caused electrical fires.

Why is wire gauge important?

Why Wire Gauge Is Important. While circuit breakers or fuses offers good protection against overloading wires and overheating them, they are not absolute protection. Both these devices are designed to sense current overloads and to trip or "blow" before the wires can overheat to the danger point.

What is wire gauge?

Wire gauge refers the physical size of the wire, rated with a numerical designation that runs opposite to the diameter ...

Can you use 16 gauge extension cords with portable heaters?

Many a household fire has occurred when a light extension cord with 16-gauge wire is used to power a heater or heating appliance of some sort. Most manufacturers will discourage the use of any extension cords with portable heaters , but if one must be used, ...

What wire do I need for a 30 amp breaker?

What wire do I need for various capacity requirements? The rule of thumb that techs will usually go by is that for a 30 amp circuit breaker, 10-gauge wire is the right one to go with. For a 40 amp you need a 8-gauge wire. For a 20 amp, you will need a 12-gauge wire. For 60 amp, the right wire size is 4, however there are certain important assumptions that that rule of thumb relies on – we will expand on those in the rest of this article. The right wire size for 50 amp is a 6, for both your breaker & circuit.

Why is the wire gauge too small for a breaker?

But if the wire gauge is too small for your breaker, the current that flows through the wire is more than what it is designed to handle. Since the wire has a high resistance, heat is generated and this will eventually be enough to melt the wires.

How to install a circuit breaker?

Remember, only perform this under the supervision of a licensed electrician until you learn to do it yourself.

How much does it take to handle 50 amps?

The truth is that 8, 10 or 12 gauge can’t handle it. The 50 amp wire size is gauge 6 in this instance, given the same conditions that we stated earlier in the article. On the other hand, you need a wire size 4 for 60 amp service, sub panel or breaker.

What does it mean when a wire is burned?

A burned wire when you inspect your circuit breaker is a surprise that you do not want to get. Fortunately, this is an avoidable scenario if you know that having the right size of the gauge wire for a circuit breaker is important. The bad news is, this is something that a lot of people; they mistakenly believe that one wire is as good as any other so they attempt to make the connections themselves instead of calling for an electrician.

How to test a breaker panel?

There should be no current in any wires in the panel. Turn off the main power and then open up the panel of the breaker. Main breaker wires will still be live so it’s important to test them and make sure no current is flowing for safety purposes. Once this is done, you can begin the process.

How to find the amperage of a breaker?

If you have no idea where to find the amperage of your circuit breaker, look for the number on the handle of the breaker itself ; this number is the maximum amperage of that breaker. Once you find the amperage of your breaker, you can now determine what wire gauge to use.