About Electrical Wire
Electrical wire is an essential component of commercial buildings all over the world. Some cables need to stand up to harsh environments, while others just need to get a signal from point A to point B. These different cables can include features like shielding and flexibility to offer the best possible performance in a wide variety of applications. However they’re made, you need to use the right one for reliable wiring.
What Is Electrical Wire?
There are many different types of electrical wiring with design features to support different environments and applications. They may need to stand up to elements like heat, high electromagnetic interference (EMI) or moisture. You can find electrical wire coated in a variety of materials or shaped in unique ways.
Some types of wire we carry, both alone and as part of a larger cable, include:
- THHN and T90 Nylon: TTHN stands for thermoplastic high heat-resistant nylon-coated wire, which is typically used in dry locations and temperatures below 90℃. It is a great choice for general building wiring.
- THWN-2 and TWN75: THWN stands for thermoplastic heat and water-resistant nylon-coated wire, and TWN refers to thermoplastic water-resistant insulated wire, nylon jacketed. Similar to THHN, THWN-2 and TWN75 are appropriate for wet environments, but at temperatures below 75℃.
- MTW: Machine tool wire (MTW) is a flexible, stranded hook-up wire, common in machine and appliance wiring and control schemes. They are appropriate in temperatures from -25℃ to 90℃.
- AWM: Appliance wiring material (AWM), as the name suggests, is often used in appliance wiring as well as general and control circuits.
Most of these wires must meet certain standards to be considered reliable and meet code requirements. These regulations include:
- ASTM International standards
- UL Standards 83, 1581 and 1063
- Federal specification AA-59544
- National Electric Code NFPA 70
- National Electrical Manufacturer’s Association (NEMA) WC-70 Construction Requirements
- Restriction of Hazardous Substances (RoHS) and Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) compliance
Cables That Use THHN Wires
THHN is a popular type of wire with several variations. When three electrical cables all use the same THHN wire conductors, what sets them apart? The amount of protection in the overall jacket.
1. Romex® Cable
Romex® cable uses THHN wires and an overall PVC jacket rated for indoor use only. The thin PVC jacket is designed to be cost-effective rather than a universal cable that can be used indoors and outdoors. The jacket wraps the conductors together for ease of installation rather than protection.
2. MC Cable
MC Cable, or metal-clad cable, is used indoors without conduit. The aluminum armor jacket acts as conduit so that you don’t have to buy Romex® cable and conduit for the same installation. MC cable also uses a green THHN insulated electrical wire for a ground instead of a bare copper ground which allows it to be used outdoors.
3. UFB Cable
UFB cable offers the most protection with a strong PVC jacket the covers each THHN wire individually. Each electrical wire is secure in its position and it looks difficult to damage. UF stands for underground feeder because it can be used outdoors and directly in the ground.
3 Stranding Options for Electrical Wire
Each wire in a cable can join up with other wires through stranding. Here are a few of the ways it can be done.
1. Solid Copper
Solid copper stranding means that there is a single strand of copper acting as the conductor. Common sizes of THHN wire that use solid stranding are 14, 12 and 10 American wire gauge (AWG). NMB and UFB cable also use solid stranding for the 14, 12 and 10 AWG cables.
Contractors, electricians and installers use these sizes of electrical wire in homes and buildings. They want the cables to be stiff instead of flexible so that they hold their form during installation. An extension cord on the other hand, is manufactured very flexible so that the user can handle it easier on a daily basis.
Stranded wires use multiple smaller AWG’s and wind them together to get the same diameter as a solid strand would be. For instance, instead of using a single 10 AWG solid strand of copper one could also get a 10 AWG wire with 19 strands. Obviously those 19 strands are not all 10 AWG or it would be much larger in diameter. The math is calculated to determine what size is needed for 19 strands to equal 1 strand of 10 AWG copper. That way, both diameters of copper, solid or stranded, both exert the same amount of current.
3. Flexible Stranding
Typically, electrical wire used in homes or buildings does not come in a flexible option because the cables are installed and never touched again. However, extension cords and power cables are uncoiled to be used for the day and the coiled back on to the reel for later use. Generator cables and welding cable come to mind as flexible cables with very thin stranding.
If you need a flexible cable we can most definitely upgrade your electrical wire to a power cable. Just remember that power cables have a lot of design involved in them for outdoor wear and tear that feed into the price such as flexible stranding and thick rubber insulation.
5 Popular Types of Electrical Wire
While there are many types of electrical wire, here are a few of the most common ones.
1. Indoor NMB cable or Romex® 12/2 cable
NMB stands for non-metallic because it has a PVC jacket instead of a metal-clad jacket. It is a basic indoor electrical wire used to deliver power from an electrical box to lights, outlets and appliances. It cannot be used outdoors because the jacket is not prepared to handle the wear and tear.
2. MC 12/2 Electrical Wire
These MC wires have interlocked armor surrounding the THHN wires. The aluminum armor also acts as conduit when used for indoor applications. Many times NMB electrical wire is required to be installed within conduit for indoor applications, but now MC cable can act as the electrical wire and conduit in one.
3. UFB 12/2 Electrical Wire
This UFB wire has the necessary protection to allow it to be buried in the ground without any additional conduit, raceway or tray. There is a slightly higher cost for UFB because it has more to offer than NMB cable and MC cable.
4. Tray 12/2 Electrical Wire
Tray cable is also a direct burial cable like UFB cable. However, UFB cable is “flat” which means each conductor lies next to each other as if they were lying on the floor next to one another. Tray cable is round which means the wires are slightly twisted together with the jacket surrounding them. Tray and UFB have slightly different applications so be sure to discuss each situation with your supplier or electrician first.
5. PLTC 12/2 Electrical Wire
PLTC stands for Power Limited Tray Cable. Power Limited means 300 volts instead of 600 volts. Simply saying “tray cable” will call out 600 volts. PLTC electrical wire is commonly used for electronic applications rather than electrical, but they have very similar attributes when compared to each other.
As you can see there are slight differences between each type of electrical wire. Putting the wrong type of wire in the wrong application could cause many problems such as a jacket that got eaten away too soon, too much voltage traveling through the cable or even that you paid too much for your product because you didn’t understand enough about the cable characteristics.
Bulk Electrical Wire for Sale at WesBell Electronics
WesBell Electronics has been selling electrical wiring for years, and we’ve been listening to our clients about what they need from their electrical wire supplier. We carry an array of products and can help you find the right one for your project. We can even help with electrical wire processing services, such as cutting to size and preparation, to speed up your installation.
Buy electrical wire online from WesBell for quality products and expert service. Reach out today if you have any questions!