Electric current

Types of electrical cables: High and low voltage guide

Types of electrical cables: High and low voltage guide

Power cables are essential components in any electrical system, from the smallest electronics to large-scale power distribution networks.

There are many classifications of electrical cables depending on the application, the conductive material, the insulation and coating, or the regulations and standards applied. In this article we will focus on low and high voltage cables and briefly describe other common cable types.

Low voltage power cables

Low voltage electrical cables are those designed to transport electricity at voltages less than 1,000 volts (1 kV). They are used in a wide variety of applications, from residential electrification to industrial control systems.

Below are some examples of common electrical cable types used for low voltage:

THHN/THWN (Thermoplastic Nylon) cable

THHN (Thermoplastic Insulated Nylon Sheath) and THWN (Thermoplastic Insulated Nylon Sheath Waterproof) cables are widely used in residential, commercial and industrial electrical installations.

These cables are characterized by:

  • Water Resistance: The nylon coating on THWN cables makes them suitable for use in wet and outdoor environments, such as aerial connections.

  • Flexibility: THHN/THWN cables are flexible and easy to handle, making them easy to install in conduit and cable trays.

  • Amperage Capacity: These cables have an adequate amperage capacity for most residential and commercial applications.

  • Insulation: PVC (polyvinyl chloride) insulation in most cases provides protection against short circuits and other electrical problems.

Romex Cable (NM)

Romex cable, also known as NM (Non-Metallic Sheathed) cable, is a type of electrical power cable used in residential and commercial applications to carry electricity from the main distribution panel to electrical devices, outlets, switches and lighting systems. inside a building.

It is a common choice for the internal electrification of homes and similar structures.

Some key features of Romex cable are:

  1. Construction: Romex cable generally consists of one or more solid or stranded copper conductors, insulated with white or yellow PVC (polyvinyl chloride) insulating material.

  2. Outer sheath: The insulation of the conductors is covered by an outer layer of non-metallic PVC, which is resistant to wear and abrasion. This coating is what gives it its name "Non-Metallic Sheathed".

  3. Available Gauges: Romex cables are available in different gauges (conductor thickness). The most common gauges include 14, 12, and 10.

  4. Ease of Installation: One of the advantages of Romex cable is its ease of installation. The insulated conductors and outer jacket allow for easy installation by inserting into conduits, fixing to walls and ceilings, or routing through construction spaces.

Solar Cable (Photovoltaic Cable)

Solar cable, also known as PV cable, is a type of electrical cable designed specifically for solar energy applications.

The photovoltaic cable has insulation resistant to ultraviolet (UV) radiation and weather, making it suitable for outdoor use. Additionally, it is often flexible to facilitate installation in photovoltaic systems.

Cable Type SJT (Service Junior Thermoplastic)

SJT type cables are common in applications where high flexibility is required, such as in power tools and household appliances. Its features include:

  • Flexibility: SJT cables are designed to withstand repeated bending without damage, making them ideal for mobile applications and portable power tools.

  • Durable Jacket: The outer jacket of these cables is designed to resist wear and tear, extending their life.

  • Availability in different gauges: SJT cables are available in different thicknesses, allowing them to handle a variety of current levels.

SJOOW Type Cable (Service Junior Oil Resistant)

SJOOW cables are similar to SJT cables in terms of flexibility, but are designed specifically for applications where there is the potential for exposure to oils, chemicals, and extreme temperatures.

Its main features are:

  • Chemical resistance: The insulation and outer jacket of SJOOW cables are resistant to a variety of chemicals and oils, making them suitable for industrial environments.

  • Wide temperature range: They can operate in extremely cold or hot temperatures, making them versatile in industrial applications.

SOOW Type Cable (Service Oil Resistant)

SOOW cables are similar to SJOOW cables but are designed for even more demanding applications. Its features include:

  • Extreme Oil and Chemical Resistance: SOOW cables are designed to withstand harsh industrial conditions, including exposure to harsh oils and chemicals.

  • Flexibility: Despite their strength, these cables are flexible and suitable for mobile environments and heavy industrial applications.

  • Abrasion Protection: They have an abrasion-resistant cover to withstand wear and tear in harsh environments.

Other types of electrical cables

There are several types of cables that cannot be classified as high voltage cables or low voltage cables, since their main function is not related to the transmission of electrical energy or the transmission of data through electrical signals.

Some examples of these cables include:

Charging and data transfer cables (USB, USB-C, Lightning)

Types of electrical cables: High and low voltage guideThese cables are used to charge electronic devices such as mobile phones and tablets, as well as to transfer data between devices. Although they do not carry high voltage power, they are not low voltage cables in the traditional sense either, as they are not designed for the distribution of electrical power in buildings or electrical infrastructure.

audio and video cables

These cables are used to connect audio and video devices such as speakers, televisions, DVD players, and sound systems. They transmit audio and video signals rather than electrical power, so they do not fit into the high or low voltage categories.

Sensor and control cables

These cables are used to connect sensors, transducers and control devices in industrial automation and process control applications. They transmit low current and low voltage signals to measure and control devices, but are not intended for large-scale electrical power transmission.

Fiber optic cables for sensors

Like conventional fiber optic cables, these cables use optical fibers to transmit light signals instead of electricity. They are used in applications where high precision in sensor measurement is required.

Ethernet Network Cables

While Ethernet cables are used for data transmission in computer networks and communication systems, they do not carry high voltage or low voltage electricity in traditional electrical power supply terms.

High voltage power cables

Types of electrical cables: High and low voltage guideHigh voltage cables are designed to carry electricity at voltages greater than 1,000 volts (1 kV). These cables are used in electrical power transmission and distribution applications, as well as high voltage industrial applications. Here are some examples of cable types used for high voltage:

XLPE high tension cables

These cables use cross-linked polyethylene (XLPE) insulation to withstand voltages up to several hundred kilovolts. They are widely used in electrical power transmission and distribution systems.

High voltage submarine electrical cables

Designed for underwater applications, these types of cables are protected against moisture and adverse environmental conditions. They are used to connect islands, oil platforms and for interconnection between countries through submarine cables.

Oil-impregnated paper cables

Although less common in modern applications, these cables were historically used in high voltage systems. They consist of conductors insulated with paper impregnated with mineral oil to improve dielectric strength.

Cross-linked polyethylene (TRXLPE) cables

These cables use thermoset-type cross-linked polyethylene as insulation, making them suitable for high voltage applications, including transmission and distribution systems.

Gas Insulated High Voltage Electrical Cables (GIL)

These cables use insulating gas, such as sulfur hexafluoride (SF6), to provide high dielectric strength. They are used in high voltage applications, such as electrical substation connections.

Oil-insulated high-voltage cables

Used in high voltage applications, these cables use dielectric oil to provide insulation. They are common in electrical energy transmission systems.

Copper Clad Aluminum Cables (ACSR)

Although they are not insulated cables, they are used in high-voltage transmission lines to carry electrical current over long distances. They are composed of a steel core and copper-clad aluminum conductors.

These types of electrical cables are cheaper but require a larger diameter to carry the same amount of current as an equivalent copper cable.

Publication Date: August 30, 2023
Last Revision: August 30, 2023