It can be tough sometimes to find the wire you need for a specific project.
Different wires have different uses, and there isn’t one type that can do everything (if there was, that person would be sitting on a goldmine).
Every wire type is specifically designed to address unique situations. Some are great for home electrical uses, while others are best used in commercial and industrial applications. Some, like tracer wire, can be buried, yet others are known for their fire, water, or corrosion resistance.
So, within this tangled web of wires, how does someone know which ones are best suited for the job? It’s all in the letters.
XHHW, PV, AWM, CPC, and THHN might mean nothing at first glance, but the letters used to describe those wires and cables can tell a lot about their attributes and how to use them best. We’ve outlined nearly three dozen acronyms to explain what the letters used to describe them mean and where they might fit in on the job site.
AC – This stands for alternating current, which reverses its direction in constant intervals. This is the type of current used to power appliances, electronics, and other items we use every day.
Al or Alum wire – Alum is short for aluminum. Aluminum is a lightweight wire option and can be used for electrical installations but isn’t as conductive as copper. When using aluminum instead of copper, gauge sizes must be increased to compensate for the lower conductivity.
Aught – When used to describe wire, this word takes the place of zero. For example, a wire that is AWG size 0000 would commonly be called 4/0, pronounced as “four aught.”
AWG – American Wire Gauge. This standardized measurement is used across North America (the United States, Canada, and Mexico). Smaller numbers are used to signify larger-diameter wires. AWG sizes range from 0000 (4/0) to 40, where 0000 is the largest and 40 is the smallest. Generally, even numbers are used for AWG measurements, though odd number measurements may be used for specialized applications.
AWM – Appliance Wiring Material is like Machine Tool wire but is not meant for wet locations. It’s primarily used in internal appliance wiring, including control panels, refrigeration, air conditioning, and machine tools.
BOS – Balance of System. This includes every piece of a solar PV system, ranging from the solar panels and wiring to mounting systems, inverters, combiner box or battery system, and chargers.
CCS – Copper Clad Steel. This tracer wire has high tensile strength, making it exceptional for directional boring applications. It can also be used as a standard tracer wire to locate buried underground pipes.
CP Cable – Cathodic Protection Cable protects steel containers and structures from corrosion. This cable serves as a sacrificial wire and is meant to reduce the damage done to metal products by salts, chemicals, and water.
CT Wire – Cable Tray, or CT wire, is a single conductor wire that is size 1/0 or bigger.
Cu Conductor – Copper conductors, sometimes seen written as Cu conductors, are the standard wires used in electrical applications. Copper is more conductive than aluminum, stronger, and can better adapt to different applications.
DC – Direct (or DC) current occurs when electricity moves in only one direction. Thanks to Thomas Edison, this is what early electric lightbulbs used.
E-1 Color Code – The E-1 color code signifies tray cable conductors and prevents confusion during installation. E-1 uses a black, white, red, green, etc. color code to mark conductors, then uses the same colors in the same order with a tracer stripe for additional numerical conductors.
E-2 Color Code – The E-2 color code signifies tray cable conductors during electrical installs. E-2 color codes use black, red, blue, orange, etc. to mark the initial conductors, then use the same colors in the same order with a tracer stripe for additional numerical conductors.
HDD – Horizontal Directional Drilling wire. During drilling, this wire will run inside the drill string and transmit information like drill angle, rotation, and temperature back to the surface.
HDPE – High-Density Polyethylene. Rigid, strong, and slippery, HDPE is typically used as insulation for tracer wire.
HMWPE Tracer Wire – High-Molecular-Weight Polyethylene tracer wire is used to help locate underground utilities like water mains, gas lines, sewer pipes, and telecommunication lines. Depending on the application, either HDPE or LLDPE can be spec’d in for the job.
kcmil – 1,000 circular mils. Like MCM, kcmil is used to determine the cross-sectional area of a wire. The higher the kcmil is, the more electrical current it can carry.
LLDPE – Linear Low-Density Polyethylene. LLDPE is not as strong and rigid as HDPE but is used for tracer wire insulation when workers need more flexibility without sacrificing chemical resistance or direct burial qualities.
LSZH – Low smoke, zero halogen cables are used where the wire will be exposed to heat or potential fire hazards. LSZH wires are unique because they don’t produce much smoke or release halogens if they catch fire.
M-4 Color Code – The M-4, or Method 4, tray cable color code uses only black conductors but marks each one with the numerical and spelled-out version of each number. Examples would be “1-One,” “2-Two,” and “3-Three.”
MC Cable – Metal Clad cable is a type of wire used for service and branch circuitry. It typically contains several conductors surrounded by a smooth, ridged, or other metal tubing. Due to its metal tubing, it does not need to be run through a conduit.
MCM – MCM measurements are used to determine the cross-sectional area of a wire. These wires are larger than AWG and aught sizes.
MTW – Machine Tooling wire. This wire is typically used in dry or wet building applications, primarily for internal wiring in appliances like air-conditioning, refrigeration, automatic washers, and other machine tools.
MV-105 Cable – This stands for Medium Voltage, with a maximum temperature of 105C. This cable is used for commercial, industrial, and utility applications. It can be used in wet or dry areas as part of circuits of less than 15,000 volts.
NEC – The National Electrical Code NFPA 70 is published by the National Fire Protection Association. The code book is updated every three years and serves as a guide for electrical workers. Although widely used to ensure safe electrical installations, the NEC code book is not a federal mandate.
PE – Polyethylene. This polymer is used to insulate many different wires, including tracer wire, RHH, and XHHW. It comes in several forms, including HDPE and LLDPE, and is usually mixed with an additive to help make it more flexible to work with.
PV Wire – Stands for photovoltaic wire. PV wire is used to connect solar panels together and to transfer power to the conductor box.
PVC – Stands for Polyvinyl Chloride. This synthetic polymer is sometimes used as insulation and jacketing for Kris-Tech’s extruded wires, including our irrigation wire, tray cable, and tinned THW-2 grounding wire.
RHH – This is a wire with XLPE insulation and high heat resistance. RHH has a similar use case to RHW cable but pays for its higher heat tolerance by not having water resistance.
RHW (RHW-2) – RHW is an underground service entrance cable rated for direct burial. It has cross-linked polyethylene insulation around the conductors and is heat- and water-resistant.
SE Cable – Service Entrance cable. This insulated and jacketed outdoor cable delivers power from the utility pole to the building or house. If there is a “U” at the front of this cable designation, it is rated for underground use.
SIS – Also known as switchboard wire or panelboard wire. Kris-Tech’s SIS wire is dual-rated and can serve as XHHW-2 in some cases.
THHN – THHN stands for thermoplastic high-heat resistant, nylon jacketed insulation. THHN is a popular wire choice for electrical applications because of its low cost, high heat and water resistance, and multiple uses. It does not work as a tracer wire replacement.
TW/THW – When you see TW or THW, these stand for Thermoplastic High Heat-Resistant and Water-Resistant. Like AWM, this wire is used in internal appliance wiring, including refrigeration, automatic washers, and control panels, and functions in wet and dry environments.
THW-2 – THW-2 is the upgraded version of the Thermoplastic High Heat-Resistant and Water-Resistant wire. It can handle temperatures up to 90C, is sunlight resistant, works in wet or dry conditions, and has PVC insulation and jacketing.
UF/TWU – Underground Feeder Cable. This wire is rated for underground burial, is sunlight resistant, and can be used to provide power from buildings to outdoor equipment.
UL – UL stands for Underwriters Laboratories, a global applied safety science company based in Illinois. Manufacturers hoping to use the UL mark on their products must meet various safety, quality, and performance standards. Like the NEC, UL marks are not federally mandated. Projects requiring UL products must have the UL mark clearly printed on the wire’s jacketing.
URD Cable – Underground distribution wires can be used in wet or dry locations and are rated for direct burial. It cannot be used inside because it is not an approved Chapter 3 NEC usage.
USE-2 – USE stands for Underground Service Entrance wire. The “-2” found at the end of the wire’s name means it is rated up to 90C, compared to standard USE wire.
V – Stands for Voltage or Volts. This is what allows current to flow through a wire or cable. As voltage increases, more current can pass through the wire at a stated resistance.
VNTC – Vinyl Nylon Tray Cable is the most seen style of tray cable, featuring PVC/Nylon conductor insulation with a sturdy PVC outer jacket. VNTC works for commercial and industrial applications and is sunlight resistant and flame retardant.
XHHW – This is XLPE (Cross-linked polyethylene) that is high heat-resistant and water-resistant. This wire is typically found in commercial buildings but can also be found in more extreme areas like power plants and mills.
XLPE – These letters describe tray cable with cross-linked polyethylene conductors and a PVC outer jacket. This tray cable works in a several locations, including raceways, cable trays, and even out in the open.
XPTC – Also known as XLPE, XPTC is tray cable that uses a set of cross-linked polyethylene conductors with a PVC jacket. It’s weather and exposure resistant, direct burial rated, and safe to use in class 1, division 2 hazardous locations.
Understanding what these letters mean is a good start, but it’s only half the battle.
Purchasing wire is about more than what type it is. Once you know what type you need, you have to figure out what gauge (or gauges) is necessary. Does it have to meet specific National Electrical Code (NEC) or National Fire Protection Association (NFPA) regulations? Do the materials have to be UL certified?
It’s a lot of information to take in, but you don’t have to go it alone. Kris-Tech has a highly experienced team of wire experts ready to help you get what you need, so you can avoid costly delays and get the right wire products delivered the first time.
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