Introduction
Hazardous areas are locations where the presence of flammable gases, vapors, or dust can potentially cause an explosion or fire. These areas can be found in a variety of industries such as oil and gas, chemical processing, and mining, among others. In order to ensure the safety of personnel and equipment, it is crucial to use specialized equipment and materials designed for hazardous areas.
In this blog, we will be focusing on one such crucial component: cables. Specifically, we will answer the question: "What cable is used in hazardous areas?" We will discuss the different types of hazardous areas, factors to consider when choosing cables, types of cables used in hazardous areas, and standards and certifications for hazardous area cables. By the end of this blog, you will have a better understanding of the different types of cables used in hazardous areas and what to consider when selecting the appropriate cables for your specific application.
Types of Hazardous Areas
Hazardous areas can be found in many industries where flammable gases, liquids, and vapors are present. They can be classified based on the type and level of danger posed by the hazardous material. There are two classification systems commonly used: the North American system and the European system.
A. North American Classification System
The North American system is based on the National Electrical Code (NEC) and is widely used in the United States and Canada. The system is divided into classes and divisions, which are defined as follows:
Classes
Class I: Locations where flammable gases or vapors are present in sufficient quantities to produce explosive or ignitable mixtures.
Class II: Locations where combustible dusts are present.
Class III: Locations where easily ignitable fibers or flyings are present.
Divisions
Division 1: Locations where hazardous materials are present continuously or intermittently under normal conditions.
Division 2: Locations where hazardous materials are present only under abnormal conditions.
B. European Classification System
The European system is based on the ATEX Directive and is commonly used in Europe. The system is divided into zones, which are defined as follows:
Zones
Zone 0: Locations where an explosive gas atmosphere is present continuously or for long periods.
Zone 1: Locations where an explosive gas atmosphere is likely to occur in normal operation.
Zone 2: Locations where an explosive gas atmosphere is not likely to occur in normal operation, but if it does, it will only exist for a short time.
It is important to understand the classification system in your region to determine the appropriate hazardous area cables and wiring methods to be used. The right cables can help prevent electrical failures and minimize the risk of explosions and fires in hazardous areas.
Factors to Consider When Choosing Cables for Hazardous Areas
Choosing the right cable for hazardous areas is essential for ensuring safety and preventing accidents. There are several factors to consider when selecting cables for hazardous areas, including:
Environmental conditions such as temperature, pressure, and humidity:
The conditions in hazardous areas can vary greatly depending on the specific location and application. For example, offshore drilling platforms may be exposed to saltwater and extreme temperatures, while chemical plants may have high humidity and corrosive substances. It is important to choose cables that can withstand the environmental conditions of the area they will be installed in.
Chemical resistance of the cable:
Hazardous areas often contain chemicals and substances that can damage cables. Therefore, it is essential to choose cables that are resistant to the specific chemicals in the area. For example, some cables are resistant to oil and gasoline, while others are resistant to acids or alkalis.
Voltage and amperage requirements:
Cables used in hazardous areas must be able to handle the voltage and amperage requirements of the equipment they will be powering. It is important to ensure that the cable has the proper insulation and conductor size to handle the electrical load.
Flexibility and durability of the cable:
Cables used in hazardous areas may be subjected to frequent movement or bending. It is essential to choose cables that are flexible and durable enough to withstand these conditions without breaking or cracking.
Compliance with industry standards and certifications:
Cables used in hazardous areas must comply with industry standards and certifications to ensure they meet safety requirements. Some of the relevant standards and certifications include NEC (National Electrical Code), IEC (International Electrotechnical Commission), and ATEX (Atmosphères Explosibles).
It is important to consider all of these factors when selecting cables for hazardous areas to ensure the safety of personnel and equipment. In addition, it is essential to choose cables that are specifically designed for hazardous locations, also known as "hazardous location cable", to ensure they meet the specific requirements of the area.
Types of Cables Used in Hazardous Areas
Several types of cables are used in hazardous areas, each with their advantages and disadvantages. These include:
1. Armored Cables
Armored cables have a metal sheath that provides physical protection against damage from crushing, impact, or abrasion. These cables are ideal for installations where the cable is exposed to mechanical stress or the risk of damage is high.
2. Shielded Cables
Shielded cables have an extra layer of insulation that provides protection against electromagnetic interference (EMI) and radiofrequency interference (RFI). These cables are ideal for installations where electrical noise can affect the performance of the system.
3. Halogen-Free Cables
Halogen-free cables are designed to prevent the release of toxic gases in case of a fire. These cables are ideal for installations where safety is paramount, and toxic fumes can pose a significant hazard to personnel.
Standards and certifications for hazardous area cables
When it comes to choosing cables for hazardous areas, it is important to ensure that they meet specific standards and certifications. These standards and certifications are put in place to ensure that the cables are safe to use and won't cause any hazards.
Here are some of the relevant standards for hazardous area cables:
National Electrical Code (NEC)
The NEC is the standard for electrical installations in the United States. It outlines the requirements for electrical systems in hazardous areas, including the type of cables that can be used.
International Electrotechnical Commission (IEC)
The IEC is a global organization that develops international standards for electrical and electronic technologies. Their standards cover a wide range of products, including cables used in hazardous areas.
ATEX
ATEX is a European directive that covers equipment and protective systems intended for use in potentially explosive atmospheres. It outlines the requirements for electrical and mechanical equipment used in these areas, including cables.
In addition to these standards, there are also various certifications that cables must meet to be considered safe for use in hazardous areas. These certifications include:
UL Listing
Underwriters Laboratories (UL) is an independent safety organization that tests and certifies products for safety. UL Listing indicates that the cable has been tested and certified for use in hazardous areas.
CSA Certification
The Canadian Standards Association (CSA) is a nonprofit organization that develops and certifies standards for products sold in Canada. CSA Certification indicates that the cable has been tested and certified for use in hazardous areas.
ATEX Certification
ATEX certification indicates that the cable has been tested and certified for use in potentially explosive atmospheres in Europe.
It is important to comply with these standards and certifications when choosing cables for hazardous areas. Non-compliance can result in serious safety hazards and legal consequences. It is recommended to consult with a qualified professional or refer to the relevant standards and certifications when selecting cables for hazardous areas.
Conclusion
In conclusion, choosing the right cable for hazardous areas is of paramount importance. Factors such as environmental conditions, chemical resistance, voltage and amperage requirements, flexibility and durability, and compliance with industry standards and certifications must be taken into account. Armored, shielded, and halogen-free cables are some of the types of cables that can be used in hazardous areas. It is crucial to comply with the relevant standards and certifications to ensure safety and legal compliance.
Read Also: Types of Cable Glands and Their Application
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