How to identify electrical cable sizes?

identifying wire size

Electrical cables are critical components that allow us to power our homes, appliances, electronics, and many devices. There are over 100 different types of electrical cable sizes. Therefore, it is imperative that we know what type of electrical cable we have before using them.

Ways to Identify Electrical Cable Sizes:

  1. Incise the Wire and Measure the Diameter

  2. This involves cutting the insulation off of the wire. You have to be careful not to cut into the wire itself as you will get the incorrect reading. After cutting some insulation off, measure the diameter of the exposed wire.

  3. Look at The Cable Insulator

The easiest way to identify electrical cable size is to look at the insulator. Most electrical wire manufacturers will stamp the wire size in AWG on the insulator. This allows anyone to simply pick up some of their wire that is lying around and know exactly what size wire it is.

How do I identify an electrical cable?

Cable identification is simple. First take out any wires not attached to anything and look at the ends of the wire. If they are bare copper, then you have copper wire. If they have some sort of sheath around them, then you have coaxial cable.

What if my wires don't have any ends?

If you do not see any ends then you have twisted pair wire. Look at the insulation and make sure it is solid. If it isn't, then you have stranded wire.

How do I tell if the wire is plastic insulated?

If the wire has an outer layer of PVC or polyurethane, then it's plastic-insulated wire. This means that it won't conduct electricity well.

What Is Wire Gauge?

What is wire gauge? Well, according to Wikipedia, wire gauge is a measure of the diameter of electrical cable (also called wire). A wire gauge is measured in thousandths of an inch. So if you take a standard 22AWG wire, then its gauge would be 0.22 (22/1000 0.22 inches) but then, if you had a 24 AWG wire, then its wire gauge would be 0.24 (24/1000 .024 inches), etc.

Importance Of Electrical Wire Gauges

The importance of electrical wire gauges are numerous. First off, they help you determine the cost of materials that you need for wiring projects. If you want to purchase wires, you must know what their wire gauge is before purchasing them. Otherwise, you might end up buying a piece of wire that is way bigger than what you need or have budgeted for. Another thing that these gauges help is determining how much space is needed for wiring projects; whether it is conduit, wiring racks, etc. Lastly, knowing the gauge helps you determine the size of equipment that can use said wire.

Choosing Electrical Wire

When choosing wires, you must think about many factors. First of all, the type of project that you are working on should affect your choice.

  • Are you wiring a home or an office building?
  • Will it be indoors or outdoors?
  • How long will it last?

All of these questions must be considered when making your decision. You also need to consider the voltage that the wire is rated for; not only does this affect the safety of using the wire, but it affects the life expectancy as well. High voltage wires tend to break quicker than low voltage wires. Also, a good rule of thumb is that the thicker the wire, the lower the current capacity.

What makes a good flexible cable?

A good flexible cable should have a low internal resistance and high yield capacity, should not be exposed to corrosion and a high level of flexibility. A good flexible wire should have an excellent conductivity, high tensile strength and be resistant to oxidation and chemical degradation.

How do you wind wires?

The winding method is the most popular way of making cables.

  • To wind wires, first use a twister spool.
  • Next, insert each wire individually into the central hole using a twisting tool known as a slitter.
  • Repeat this procedure until you have used up all the spools of wire.
  • Once completed, the resulting bundle is then coiled onto itself to create the final product.

What does the term core mean?

In electrical engineering, a core refers to an inner conductor wrapped around an insulation material. In communication systems, cores refer to the center conductor inside of a coaxial cable. There are two types of cores: single-core and multicore.

Describe the difference between a single and multicore cable.

Single-core cables consist of a single insulated wire surrounded by a metallic sheath. On the other hand, multicore cables have several insulated wires wrapped around a common metal shield.

What is a twisted pair?

Twisted pairs, or twinax, consist of two copper wires twisted together at right angles. Each wire carries its own signal and they are both connected to a connector. Twisted pairs offer many advantages over plain old shielded copper wire, including reduced EMI emissions and reduced crosstalk, or interference between individual signals.

Three applications where multicore cable may be useful.

Multicore cable can be used in any application where the cable length must be kept short. Short lengths of multicore cable allow the user to minimize losses of signal quality or even eliminate them altogether.

Explain how multicore cable can help reduce cross talk.

MultiCore cables can reduce crosstalk problems associated with regular shielded cable by providing enough shielding to prevent noise from getting into the system.

Wire Color Coding

Wire color coding is a method used to identify wires based upon their purpose. There are three types of wire color coding, solid, stranded, and stranded-solid. By understanding each type of wire color coding, we will know what they mean and how they can be useful. When working on construction projects, it is imperative to understand these different types of wire color coding.

Solid wiring

Solid wire color coding refers to solid copper wire, which is used for grounding purposes. Grounding is done to ensure safety for people installing electrical systems.

Stranded wire

Stranded wire color coding refers to multi-strand copper wire. Multi-strands of wire are used to connect devices together. A device may have many connected components. Each component requires its own set of wires to work properly. These wires should not touch each other or any metal objects.

Stranded-solid wire

A combination strand is a mix between solid and stranded wire. A combination strand is sometimes called twisted wire, which means that strands of regular copper wire and multi-strand wire are twisted together. Combination strands are used to provide additional reinforcement for the wiring system.

Types of Wiring System

There are various types of wiring system in use today. There are two basic types of wiring system; single and dual circuit. In both cases, the wiring system consists of four primary parts.

  • Cables
  • Cables are wires or cable strands that are composed of many individual wires wrapped together. There are two types of cables: insulated and non-insulated. Insulating material adds weight and insulation to reduce voltage loss. All wires have to have at least 0.02 inches (0.5 mm) of insulation around them.

  • Connectors
  • A connector is a device that joins two pieces of metal together. On copper and aluminum wiring, the connector keeps the electrical current flowing in the correct direction and makes sure that each wire connects safely to its destination. Connecting terminals to conductors is done using screw terminals, solder, crimp connectors, wedge connectors, and snap connectors. Screw-terminal connectors are commonly used and consist of a threaded post and nut. Crimp connectors and wedge connectors are similar in design, but use a different method to connect. Snap connectors are spring loaded and use pressure to attach the wires. Solder may be applied to any connection point where the wire meets the terminal.

  • Circuit breaker boxes
  • A circuit breaker box is a type of switchboard designed specifically for the distribution of electricity. A circuit breaker is a protective device that opens or interrupts a circuit under certain conditions, such as overload or short circuits. In residential settings, circuit breakers protect people from electrocution. Generally, they work as follows: If a fault occurs and the breaker senses that the current exceeds a preset limit, it will open and not allow any further flow of power. The breaker should then automatically reset once the fault is cleared.

  • Terminals
  • Terminals are points of contact between the wires of a wire bundle and the devices that are connected to the wire bundle. Each wire bundle may contain several sets of terminals, depending on whether the ends of the wire bundles need to be stripped. Wire bundles often carry alternating currents. When conducting alternating current, the polarity of the end of the wire bundles alternates with each cycle of AC. As a result, two opposite poles of a neutral wire are attached to a single set of wires. The conductor's polarity changes based on the direction of travel of electricity in the wire bundle. One way to identify the polarity of a wire bundle is to look at the white stripe near the center of the wire bundle. This white stripe represents the positive terminal of the conductor. To strip the ends of wire bundles, unscrew the cap of the terminal and pull out the wire. Then strip the exposed portion of the wire and replace the cap.

Things to look for in a wire

  1. Carrying Capacity

  2. The current carrying capacity refers to how much electrical power a wire or cable can safely handle before breaking. There are many factors that go into determining this value including the size of the wire, the voltage drop across the wire, and the temperature of the wire. Generally speaking, a copper wire can carry around 35 amps before it breaks. Copper wires (wires made out of pure copper) are often used in high-current applications, like motor control circuits, that require a lot of electricity. If the wire becomes damaged, it can short-circuit. When this happens, all of the electrical current passes through the wire instead of flowing through the load. The wires become hot and eventually burn out.

  3. Voltage Regulators

  4. A voltage regulator controls the amount of volts being sent down the line. You may have seen these components at work on older appliances like microwaves or hair dryers, where they regulate the voltage coming off of the wall socket. A regular wall plug doesn't deliver enough volts to operate electronics properly, so a voltage regulator steps up the available voltage to make sure your device gets the right voltage. In electronics, the term "volts" refers to the potential difference between two points. Volts determine what we call direct current (DC), alternating current (AC), or radio frequency (RF). DC is the type of electricity generated by generators. You might remember seeing a generator hooked up to a car battery; this produces DC electricity. AC is the type of electricity produced by electric motors, fluorescent lights, and even solar panels. RF is the type of electricity used in radios and cell phones.

  5. Short Circuit Rating

  6. When wires get hot, they can start to melt. And if the melting point of the wire isn't great enough, it could burn out. To prevent this from happening, manufacturers set maximum ratings for wires based on how much current they can take safely. These limits are called the "short circuit rating." If wires with a higher short circuit rating do break, then the metal inside the wires melts away and shorts out. If this happens, the wires should be replaced immediately. Most people think of wires as being insulated, which makes sense since you wouldn't want to touch them directly. But just like the heating elements in your stove top or oven, the metal cores of cables are covered in insulation. However, this insulation doesn't stop those metallic cores from getting hot. Insulation prevents wires from touching each other and keeps the current from spreading between wires, but it's not capable of stopping the flow of electricity when things get too hot.

  7. Electrical wire run length in feet

  8. Most electrical wiring projects require that you know how long each wire run should be before you install any cable. Electrical wires have two purposes; they supply electricity throughout your home or building and they carry data signals between devices. The maximum allowable distance for a metal wire run is 100 ft (30 m). If you exceed this limit, you run the risk of damaging either the device that receives power or the device that provides power. These types of damage are both costly and dangerous. You may think that the wiring runs don't really matter, but they do! It's not just about the wire running past the fuse box to the outlet strip anymore. It's about all of the connections that make up the circuit.

  9. Voltage drop in cables

How much voltage drops across a wire? That is what you need to know in order to determine if your wiring project meets code requirements. There are four different factors that affect the amount of voltage dropped across a wire. The first factor is the size of the cable being installed. The larger the conductor (the wire inside), the greater the loss of voltage. There is no way around it. The second factor is the number of wire conductors per inch (c/in) of the cable. The third factor is the spacing between the individual conductors. And the final factor is the gauge of the wire being used. Again, the higher the number, the greater the loss of power.

Voltage Drop Per 100 FT Run of Paired Wire

Data gathered from Altronix

Gauge (AWG) .5 amp - Load Current 1 amp - Load Current 2 amp - Load Current 4 amp - Load Current 10 amp - Load Current


1.60 3.20 6.40 12.81 32.02


1.27 2.54 5.08 10.17 25.42


1.01 2.02 4.03 8.07 20.17


0.80 1.60 3.20 6.40 16.01


0.64 1.27 2.54 5.08 12.71


0.50 1.01 2.02 4.03 10.08


0.40 0.80 1.60 3.20 8.00


0.32 0.64 1.27 2.54 6.35


0.25 0.50 1.01 2.02 5.04


0.20 0.40 0.80 1.60 4.00


0.16 0.32 0.64 1.27 3.18


0.13 0.25 0.50 1.01 2.52


0.10 0.20 0.40 0.80 2.00


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When choosing wire sizes, it’s helpful to think about how it’ll be connected to something else, and how much amperage it might need to withstand. Learning how to figure out wire sizes is a skill that mnost people do not think they need but eventually realize that it can be helpful.

We hope this article has helped you understand how to identify electrical wire sizes. If you have any tips, please leave us a message.

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