What are the installation guidelines for an aluminum cable tray in a hazardous area?

What are the installation guidelines for an aluminum cable tray in a hazardous area?

As a seasoned supplier of Aluminum Cable Tray, I understand the critical importance of proper installation, especially in hazardous areas. Hazardous areas, where the presence of flammable gases, vapors, dusts, or fibers can create potentially explosive atmospheres, demand the highest standards of safety and compliance. In this blog post, I will share the essential installation guidelines for aluminum cable trays in such challenging environments.

Understanding Hazardous Areas

Before delving into the installation guidelines, it's crucial to have a clear understanding of hazardous areas. These areas are classified based on the frequency and duration of the presence of explosive atmospheres. The two main classification systems are the International Electrotechnical Commission (IEC) system and the North American system.

In the IEC system, hazardous areas are divided into zones:

• Zone 0: An area in which an explosive gas-air mixture is present continuously or for long periods.
• Zone 1: An area in which an explosive gas-air mixture is likely to occur in normal operation.
• Zone 2: An area in which an explosive gas-air mixture is not likely to occur in normal operation and, if it occurs, will exist only for a short time.

The North American system uses Classes, Divisions, and Groups to classify hazardous areas:

• Class I: Flammable gases and vapors
  • Division 1: An area where ignitable concentrations of flammable gases or vapors are present continuously or intermittently under normal operating conditions.
  • Division 2: An area where ignitable concentrations of flammable gases or vapors are not likely to occur under normal operating conditions.
• Class II: Combustible dusts
• Class III: Ignitable fibers and flyings

Selecting the Right Aluminum Cable Tray

The first step in a successful installation is selecting the appropriate aluminum cable tray for the hazardous area. Consider the following factors:

• Material and Design: Aluminum cable trays offer excellent corrosion resistance, lightweight construction, and high strength. However, in hazardous areas, the tray's design must prevent the accumulation of flammable substances and minimize the risk of sparking. Perforated Metal Cable Tray is a popular choice as it allows for ventilation and drainage, reducing the likelihood of gas or vapor buildup.
• Compliance: Ensure that the cable tray meets the relevant safety standards for hazardous areas, such as UL 508A, NEC 500, or IEC 60079. These standards specify requirements for materials, construction, and installation to prevent ignition sources and protect against explosive atmospheres.
• Size and Capacity: Calculate the number and size of cables to be installed in the tray and select a tray with sufficient capacity. Overloading the tray can lead to overheating and increase the risk of fire or explosion.

Installation Location and Support

The location and support of the cable tray are critical for its safe and effective operation in a hazardous area.

• Location: Avoid installing the cable tray in areas where it may be exposed to direct sources of ignition, such as open flames, hot surfaces, or electrical equipment that can generate sparks. Keep the tray away from areas where flammable substances are likely to accumulate, such as floor drains or sumps.
• Support: Proper support is essential to prevent the cable tray from sagging or collapsing under the weight of the cables. Use sturdy supports, such as brackets, hangers, or struts, and ensure that they are securely attached to the building structure. The spacing between supports should be based on the tray's size, load capacity, and the manufacturer's recommendations.

Grounding and Bonding

Grounding and bonding are essential safety measures in hazardous areas to prevent the buildup of static electricity and ensure electrical continuity.

• Grounding: Connect the aluminum cable tray to a reliable grounding system to provide a path for electrical current in the event of a fault. Use grounding conductors that are sized according to the electrical code requirements and ensure that they are securely attached to the tray and the grounding electrode.
• Bonding: Bond all sections of the cable tray together to ensure electrical continuity and prevent the formation of potential differences that could cause sparking. Use bonding jumpers or conductors that are compatible with the tray material and size.

Sealing and Gasketing

To prevent the ingress of flammable gases or vapors into the cable tray, proper sealing and gasketing are required at all joints, connections, and penetrations.

• Joints and Connections: Use approved gaskets or seals at all tray joints and connections to create a tight seal. Ensure that the gaskets are made of materials that are resistant to the chemicals and temperatures present in the hazardous area.
• Penetrations: Seal all penetrations in the cable tray, such as holes for cables, conduits, or pipes, using approved sealing compounds or firestop materials. These materials should be designed to prevent the passage of flames, gases, and smoke in the event of a fire or explosion.

Cable Installation

The installation of cables in the aluminum cable tray should be carried out carefully to prevent damage to the cables and ensure proper ventilation.

• Cable Routing: Route the cables in the tray in an organized manner, avoiding sharp bends or kinks that could damage the insulation. Use cable ties or clamps to secure the cables to the tray and prevent them from moving or rubbing against each other.
• Cable Separation: Separate different types of cables, such as power cables, control cables, and communication cables, to prevent interference and reduce the risk of fire or explosion. Use dividers or barriers in the cable tray to keep the cables separated.
• Ventilation: Ensure that there is adequate ventilation in the cable tray to prevent the buildup of heat and gases. Avoid overfilling the tray with cables, as this can restrict airflow and increase the risk of overheating.

Inspection and Maintenance

Regular inspection and maintenance of the aluminum cable tray are essential to ensure its continued safe operation in a hazardous area.

• Inspection: Conduct periodic inspections of the cable tray to check for signs of damage, corrosion, or wear. Look for loose connections, damaged gaskets, or any other issues that could compromise the tray's integrity.
• Maintenance: Perform any necessary maintenance tasks, such as cleaning the tray, tightening connections, or replacing damaged components. Follow the manufacturer's recommendations for maintenance and ensure that all work is carried out by qualified personnel.

Conclusion

Installing an aluminum cable tray in a hazardous area requires careful planning, proper selection of materials and equipment, and strict adherence to safety standards and guidelines. By following the installation guidelines outlined in this blog post, you can ensure the safe and reliable operation of your cable tray system in even the most challenging environments.

If you are in the market for high-quality aluminum cable trays for your hazardous area applications, we are here to help. Our extensive range of Cable Tray and Accessories and X-tray Cable Tray are designed to meet the highest safety standards and provide reliable performance. Contact us today to discuss your specific requirements and let us assist you in finding the perfect solution for your project.

References

• International Electrotechnical Commission (IEC). IEC 60079 - Electrical apparatus for explosive gas atmospheres.
• National Fire Protection Association (NFPA). NFPA 70 - National Electrical Code (NEC).
• Underwriters Laboratories (UL). UL 508A - Industrial Control Panels.