Common Electrical Wire Material Options
With so many options available in the market, it is wise to always weigh your options and the exact wire features your kind of application require so you are able to select the most suitable one at the end of the day. It is the best way of ensuring safety when using electricity and wire materials are some of the most important to consider for any given application. What your wire is made up of determines its quality and suitability for the intended use.
Copper
It is considered standard in the wiring area with most electrical appliances relying on copper wires to transfer energy. One of the major reasons why copper is a great material is its high conductivity and flexibility. Compared to other metals, copper seems to win also in resistance to corrosion, tensile strength, ductility, thermal conductivity and also resistance to overloads. Because of the abundance of copper, the battery cable made of copper are reasonably priced.
Aluminum
It may be more abundant and cheaper compared to copper, but it is not as conductive as copper. You would need a relatively larger aluminum wire in diameter to have it functioning the same way as a copper wire. Aluminum is also not as reliable in terms of electrical safety because it can’t withstand excess heat. When going for this kind of electrical wire, especially for commercial purposes, it is best that you settle only for larger diameters.
Silver
It is a good conductor of electricity and is most suitable in high temperature conditions. Silver wires are however not that easy to bend and they can also be very expensive. In commercial applications, electrical safety would actually be compromised unless silver electrical wires are used. Most people prefer using these wires at home for their entertainment equipment because signals seem to travel far much better through pure silver compared to copper.
Tungsten
Tungsten is used when you actually want the wire to have resistance, and also have it not melt even when white-hot, as is the case in incandescent lamps.
Alloys
There are many different alloys used in electrical conductors. Here are some examples:
- Nickel-chrome (nichrome) wire, like tungsten, can survive high temperatures, and the higher resistance is desirable. Being cheaper than tungsten, is used in heater wires, where the wire doesn’t need to get white-hot.
- Solder, which is an alloy of tin and lead, or other mixes of metals in the case of lead-free solder, is used for bonding electrical components to copper pads on PCBs. The low melting temperature of tin-lead makes it suitable for this task.
- Cryogenic wire is often phosphor bronze (copper, tin, phosphorus), where the resistance of this alloy doesn’t change much at very low temperatures.
Romex Cables
Romex (shown in yellow above) is the trade name for a type of electrical conductor with non-metallic sheathing that is commonly used as residential branch wiring. In fact, Romex will be the most common cable you’ll use in wiring a house. The following are a few basic facts about Romex wiring:
- Romex ™ is a common type of residential wiring that is categorized by the National Electrical Code (NEC) as underground feeder (UF) or non-metallic sheathed cable (NM and NMC).
- NM and NMC conductors are composed of two or more insulated conductors contained in a non-metallic sheath. The coating on NMC cable is non-conducting, flame-resistant and moisture-resistant. Unlike other cables commonly found in homes, they are permitted in damp environments, such as basements.
- Underground feeder conductors appear similar to NM and NMC cables except that UF cables contain a solid plastic core and cannot be “rolled” between fingers.
Wiring Terminology
It helps to understand a few basic terms used to describe wiring. An electrical wire is a type of conductor, which is a material that conducts electricity. In the case of household wiring, the conductor itself is usually copper or aluminum (or copper-sheathed aluminum) and is either a solid metal conductor or stranded wire. Most wires in a home are insulated, meaning they are wrapped in a nonconductive plastic coating. One notable exception is ground wires, which are typically solid copper and are either insulated with green sheathing or uninsulated (bare).
UF Cable
Underground Feeder (UF) is a type of nonmetallic cable designed for wet locations and direct burial in the ground. It is commonly used for supplying outdoor fixtures, such as lampposts. Like standard NM cable, UF contains insulated hot and neutral wires, plus a bare ground wire. But while sheathing on NM cable is a separate plastic wrap, UF cable sheathing is solid plastic that surrounds each wire. UF cable is normally sold with gray outer sheathing.
The best wire for the job:
All electrical engineers must know about wires and think about using the right design and material for the task at hand. Here are the factors for determining wire design:
- Durability (ability to flex repeatedly or be subject to crushing weights)
- Voltage and Current level
- Suspension strength (ability to hold its own weight over long spans between support)
- Underground or underwater
- Temperature of operation (like superconducting wire)
- Cost
Solid Wire:
Advantages:
Less surface area to corrode
Can be rigid and strong
Disadvantages:
Not good if flexed repeatedly, can break if flexed in the same spot
Not practical for high voltage
Stranded Wire:
Above: Stranded speaker wire found in every household
Below: Specialized use super-thick stranded copper wire
Stranded wire
lots of smaller wires in parallel, can be twisted together
Advantages:
Great conductor for its size
Disadvantages:
You may think this would be good for high frequency use because it has lots of surface area on all the little strands of wire, however it is worse than solid wire because the strands touch each other, shorting, and therefore the wire acts as one larger wire, and it has lots of air spaces which makes for more resistance for the size
Braided Wire:
Advantages:
- Great for durability compared with solid wire
- Better conductivity than solid wire (lots of surface area)
- Can act as an electromagnetic shield in noise-reduction wires
- The more strands in the wire, the more bendable and strong it is, but it costs more
Special Wires:
Solid with braided exterior or some combination of this, these wires are used for all kinds of special applications.
Coax cable is used for radio or cable television transmission because in its design braided and foil conductors on the outside keep frequencies trapped inside. The shielding prevents stray electromagnetic energy from tainting the area around sensitive receivers.