Power transmission networks in the complex field of electrical engineering depend heavily on the various types of high voltage cables and medium voltage cables.  Hv cables are crucial for contemporary electrical setups, enabling the transmission of electrical power across vast spans. They play a vital role in ensuring the secure and effective distribution of electricity to homes, businesses, and industrial areas.

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High voltage cables are classified according to their voltage handling capabilities. Cables within the medium voltage spectrum typically operate between 5 and 33 kilovolts (kV), while those in the high voltage category are designed for voltages exceeding 50 kV. This categorization is essential as it influences both the design and the specific use-case of the cables, especially electric cables employed in high voltage transmission lines. Such a classification system ensures the efficient distribution of power across varied electrical networks. This discussion aims to provide a thorough understanding of high voltage cables by examining their components, various types, and the critical factors involved in choosing the right cable for distinct applications.

Components of High Voltage Cables

Each component of high voltage cable specifications plays a crucial role in their operation and safety. The conductor, typically composed of either copper or aluminum, is responsible for transmitting the electrical current. These conductors are vital in various high voltage power cable types and come in different styles such as compact, compressed, and sectored, each tailored for specific applications and current requirements.

Insulation is another essential element, often crafted from polymer materials like XLPE (Cross-Linked Polyethylene) or EPR (Ethylene Propylene Rubber). This insulation is critical, especially in medium voltage (mv) and high voltage wires, as it needs to endure extreme voltages while preventing electrical leakage. To enhance protection, these cables also include shields and a jacket. These layers defend against physical harm and environmental factors, thereby ensuring the cable’s durability and consistent performance. Now, let’s shift our focus to the different types of high voltage cables, each designed for specific scenarios.

Also read more about high voltage cables：High Voltage Cable: Everything You Need To Know

What are the different types of high voltage cables?

• Ethylene Propylene Rubber (EPR) Cables: EPR cables are characterized by their exceptional flexibility, which is a crucial factor in installations that require cables to bend around obstacles or in mobile applications. The ethylene propylene rubber insulation is highly resistant to a wide range of environmental stressors, including ozone and ultraviolet light, chemicals, and extreme temperatures. This toughness makes EPR cables ideal for demanding environments such as industrial sites, offshore platforms and other environments where cable performance is critical.

• Polyvinyl Chloride (PVC) Insulated Cables: PVC insulated cables stand out for their adaptability and functionality. The PVC insulation strikes a harmonious balance of efficient electrical properties and physical sturdiness. PVC cables boast resistance to oxidation, chemical influences, and various climatic conditions, rendering them apt for both indoor and outdoor use. Their cost-effectiveness and simplicity in installation have cemented their popularity in commercial and residential electrical setups. Nonetheless, it’s important to note their limitations in high-temperature environments, a key consideration in the cable selection process.

• High Voltage Flexible Power Cables: Specifically engineered for scenarios requiring both high flexibility and dependable performance under high voltage stress, these cables are a staple in industrial environments. They are crucial for linking large machinery, where enduring regular movement, bending, and vibration is essential. Flexible cables are designed with durable yet pliable conductors and advanced insulation materials. This ensures consistent performance and structural integrity even in the face of constant mechanical strain.

Every high voltage cable variant possesses distinct characteristics and specific uses, underscoring the importance of grasping these variances for their efficient deployment in power transmission. Recognizing the diversity among high voltage cables is a pivotal step, leading to the essential task of selecting the most suitable one that aligns with your specific requirements.

Choosing the Right High Voltage Cable

The selection of materials, from conductors to insulators, and the structural design of these cables significantly influence their efficiency and reliability. Understanding these aspects is key to informed decision-making in power transmission and distribution, ensuring not only efficient electricity delivery but also the highest safety and reliability standards.

Types of Electrical Wires and Cables

Published April 15,

Electrical wire and cable must be sized and installed correctly to pass an electrical inspection and keep electricity running safely through your home. This guide will teach you the difference between types of electrical wires and types of electrical cables. You’ll also learn how to choose between electrical cables and wires for your projects.

Safety Tip: The National Electrical Code (NEC) and local building codes regulate the types of electrical wires and cable that can be installed in specific electrical applications.

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Table of Contents

1. Difference Between Wire vs. Cable

2. Wire Labeling

3. Wire Material

4. Maximum Voltage Rating

5. Wire Colors

6. Gauge

Difference Between Wire vs. Cable

While the terms wire and cable are often used interchangeably, technically a wire is one electrical conductor and a cable is multiple conductors, or a group of wires, encased in sheathing.

Electric wires are typically made of aluminum or copper. They are either bare or insulated and typically covered in a thin layer of thermoplastic. If they have a thermoplastic sheath, then the thermoplastic is colored to indicate whether the wire is a neutral, ground or hot wire in your electrical installation. We discuss wire colors in a section of this guide.

Cables contain at least a neutral wire, ground wire and hot wire that are twisted or bonded together. Depending on its purpose, the cable may contain more wires. The wires in a cable are insulated in their own color-coded layer of thermoplastic. The group of wires is then encased in an outer sheath to make up the single cable.

Wire Labeling

The most common types of electrical wires used in residential applications are usually nylon coated thermoplastic with a high-heat resistance. Wires are labeled with the THHN/THWN, material, maximum voltage rating and gauge.

• THHN/THWN

Here’s what the letters stand for:

T – Thermoplastic insulation

H – Heat resistant

HH – High heat resistance up to 194 degrees Fahrenheit

W – Rated for wet locations

N – Nylon-coated to resist damage from oil or gasoline

X – Synthetic polymer, flame-resistant

THHN is made for temperatures up to 75 degrees Celsius. THWN can usually handle higher temperatures in both dry and wet conditions.

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Wire Material

Most wire will be marked “CU” for copper, the most common conductor of residential electricity. Because electricity travels on the outside of copper wire, these wires are insulated to protect against fire and shock.

Aluminum wire is more conductive than copper wire, but it also degrades faster. For this reason, aluminum wire typically isn’t used in homes. Older wire could be aluminum or copper-clad aluminum. To comply with NEC guidelines, aluminum wire should only be installed by a professional electrician.

Maximum Voltage Rating

The maximum voltage rating will be a number such as 600, which indicates the maximum voltage the wire can carry. The average household voltage is 120 to 240 volts.

To calculate the maximum wattage a wire or cable can hold, multiply amperage by voltage. Amps x Voltage = Watts.

• Amperage: strength of an electrical current
• Voltage: electrical force needed to drive a current between two points
• Wattage: amount of electricity used

Wire Colors

A wire’s color tells you the purpose of the wire. The NEC references the white conductor as the grounded conductor, the green or bare as the equipment grounding conductor, and the other colors as the ungrounded conductors. Typically, white wire is neutral wire and green or bare wire is ground wire. Any other color is usually a hot wire that carries an electrical current.

• White insulation: Typically considered neutral but can sometimes be used as a hot lead in certain situations, such as switch loops. In existing wiring jobs, white wires may also be marked with black or red to indicate that it’s now a hot wire.
• Green insulation and bare copper: Ground wire.
• Black insulation: Hot wire for switches and outlets.
• Red insulation: Hot wire for switch legs and hardwired smoke detectors.
• Blue/Yellow insulation: Hot wire pulled through a conduit.

Safety Tip: Always test wires with a volt checker. A neutral can be just as dangerous as a hot wire. It still has the potential to electrocute you. It can also "ground out" and electrify any metal it meets. Treat every wire as though it’s a hot wire. If you have any uncertainty as to whether a white wire is used as neutral or hot in a project, check with a professional electrician.

Gauge

The wire gauge indicates the electrical wire sizing, as defined by the American Wire (AWG) system. The most common gauges are 10, 12 or 14. The gauge and diameter of the wire are inversely related. In other words, as the gauge number gets higher, the diameter of the wire gets smaller. For example, a 10-gauge wire is bigger than a 12-gauge wire. Larger wires can carry more amperage and wattage than smaller wires.

Tip: If a project calls for longer lengths of wire (such as 80 or more feet from the breaker), increase the gauge size to ensure that enough electricity can pass through it.

Recommended Amperage Loads

The below electrical wire sizing shows both the recommended and the most common wire gauges. Here are the recommended uses for each gauge.

Wire and Cable Gauge: 14-gauge

• Recommended 80 Percent Wattage Load: watts (120 volts)
• Max Wattage Load: watts (120 volts)
• Recommended for common residential wiring: Light fixtures, household receptacles

Wire and Cable Gauge: 12-gauge

• Amps: 20
• Recommended 80 Percent Wattage Load: watts (120 volts), watts (240 volts)
• Max Wattage Load: watts (120 volts), watts (240 volts)
• Common residential wiring: Light fixtures, household receptacles, small appliances

Wire and Cable Gauge: 10-gauge

• Amps: 30
• Recommended 80 Percent Wattage Load: watts (120 volts), watts (240 volts)
• Max Wattage Load: watts (120 volts), watts (240 volts)
• Large household appliances: Window air conditioner units, clothes dryers

Wire and Cable Gauge: 8-gauge

• Amps: 40
• Recommended 80 Percent Wattage Load: watts (240 volts)
• Max Wattage Load: watts (240 volts)
• Large household appliances: Electric ranges, central air conditioning

Wire and Cable Gauge: 6-gauge

• Amps: 55
• Recommended 80 Percent Wattage Load: watts (240 volts)
• Max Wattage Load: watts (240 volts)
• Large household appliances: Central air conditioning, electric furnace

Cable Labeling

All the information you need to know about a type of cable is printed on its sheathing. Use the following to determine if a cable is right for a project:

• Type: Will list the type of cable, such as NM-B or UF.
• Gauge: The gauge of the individual wires inside the cable, such as 14, 12, 10 and more.
• Number of wires: This number follows gauge. For example, 14/2 indicates that there are two 14-gauge wires (a ground wire, if part of the cable, is not included in this number) within the cable.
• Grounding: The word “GROUND” or the letter “G” indicates the presence of a ground wire.
• Voltage rating: The most common rating for residential use is 600 volts, but this can vary. The number indicates the maximum voltage the cable can safely carry.
• UL: Indicates that the cable is safety-certified and approved for use by Underwriters Laboratories.

Types of Electrical Cables for Houses & Buildings

There are several different types of electrical cables. Each have their own specific purposes and applications. Below are common types of electrical cables used in homes and businesses:

NM-B Cable

• “NM” stands for non-metallic, which refers to the flexible, typically thermoplastic sheathing surrounding the cable. “B” indicates a heat rating of 194 degrees Fahrenheit, ensuring that its interior wires can operate at certain levels without overheating.
• Most common form of indoor residential electrical wiring.
• Inside the sheathing are at least two thermoplastic insulated wires of the same gauge, though different cables can have different gauges.
• For indoor use only, in spaces free from moisture and away from any heat sources. Do not bury or run outside of a wall.
• Best used behind walls and ceilings and inside floor cavities.

UF Cable

• "UF” stands for underground feeder; rated for in-ground and damp-area installation.
• Looks like an NM-B cable, but the wires are embedded as a group in solid thermoplastic (rather than individually encased in flexible thermoplastic).
• Like an NM cable, UF cable comes in a variety of gauges to meet all electrical code requirements and is labeled with the same information carried on NM cable, plus the designation UF.

AC

• “AC” means armored cable. Also known as “BX”.
• Consists of insulated hot and neutral wires and a bare bonding wire, all wrapped in paper.
• Wire enclosed in metal sheathing that acts as the grounding conductor.
• Relatively expensive and difficult to work with.
• Often found in older homes but not used in new builds.
• For indoor use only.

Metal-Clad Cable

• Similar to AC, but wires are wrapped in plastic instead of paper.
• Has green grounding wire because its metal sheathing can’t be used as a ground.
• For indoor use only.
• Not often used in residential applications.

Types of Electrical Cables for Electronics, Lamps & More

Coaxial Cable

• Usually called “co-ax.”
• Metallic cable often used to carry television signals and connect video equipment.
• Features central wire conductor covered with a dielectric or non-conducting insulator. The insulator is surrounded by mesh or a metal sheath and covered by a thin plastic layer for protection.

HDMI Cable

• Rubber cable often used to transmit digital video, multi-channel surround audio and advanced control data through a single cable.
• An all-digital, audio-video interface which carries signals in uncompressed format.
• Cost-effective.
• HDMI connector types: Type A/B are defined in the HDMI 1.0 specification, type C is defined in the HDMI 1.3 specification and type D/E is defined in the HDMI 1.4 specification.

Speaker Cable

• Used to make the electrical connection between loudspeakers and audio amplifiers.
• A zip-cord type of electrical cable where two or more electrical conductors are individually insulated in a plastic or rubber that can be easily pulled apart.

Category 5e Cable

• Usually called “cat-5e” or ethernet cable.
• Industry standard for unshielded twisted-pair cables (UTP) for connecting , computer, home automation and A/V networks.
• Copper cabling typically consists of 4 pairs of wire (8 total conductors) wrapped in a single jacket.

Lamp Wire

• SPT-1 and SPT-2 is intended for use in small household appliances, including lamps, clocks and fans.
• Not subject to hard usage.
• SPT-1 and SPT-2 conductors are rated for use up to 105 degrees Celsius.

Landscape Cable

• May be used as low-voltage (low-energy) underground.
• Security and outdoor accent lighting applications.
• Not to exceed 150 volts when installed as specified by the National Electrical Code® (NEC) and other applicable standards.
• Sunlight and UV resistant.
• Suitable for direct burial.
• For use at temperatures between -20 degrees Celsius and 60 degrees Celsius.
• Copper conductors.

Sprinkler System Cable

• May be used for connecting field and central controls up to 30 volts.
• Available with 4, 5, 7 or 10 copper conductors and in 50-, 100- and 500-foot lengths.
• Sunlight resistant and suitable for underground applications.
• Insulation rated at 60 degrees Celsius.

Tip: Both NM and AC cable require special cutting tools that cut the sheathing but not the internal wires. They also require bushings inserted in the ends to prevent the sharp edges of the metal from damaging the wires. Special electrical boxes and connectors are also required.

Knowing how to tell the difference between types of electrical wires and cables ensures that your home's power supply operates at peak efficiency and safety. Check with your local building inspector before starting any electrical wiring and cable project. Be sure to obtain required permits and have them inspected for compliance with local codes once complete. Need help identifying a tool or material? Find products fast with image search in The Home Depot Mobile App. Snap a picture of an item you like and we'll show you similar products.

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