22-February-2022 || By: Admin
The main purpose of a
It is important to consider all parameters while choosing and installing cable trays in order to ensure the safety and effectiveness of the wire cables. Effective application of cables that run through the structural systems outdoors is essential for protection of wire cables from mechanical wear and tear, electrical safety and space optimization.
The first most obvious practice is that you should choose the right cable tray as per the application. Commercial industrial rooftops usually have a number of cables running across them that carry high and low-voltage electrical current to meet the specific power and communication needs on ground.
It becomes important to protect not only the cables but also the insulation around them. Try to avoid cables sag between wire cable trays, as it can lead to wear and tear of parts and eventually cause damage to the wire system. One crucial aspect is to protect the insulation to avoid any hazards. One way to protect the insulation is to de-energize wire cables during new cable tray system installation. As per the outdoor rooftop condition, area size, building structure and length available the perfect cable tray systems and types of cable tray is decided and installed.
Cable tray expansion joints are important for effective usage of cable tray management considering variable temperature range in outdoor rooftop setup. Continuous exposure to summer heat and cold winters there result in expansions and contractions of installed cable trays. Due to these conditions, the cable tray structures face heavy stress causing them to tear loose from their cable tray support in the absence of expansion joints.
An expansion joint is the point where different cable trays meet and are connected along the connector plate. These joints give freedom for each tray to move inward or outward, depending on temperature. The two connecting trays are attached to one another using a strip that can stretch or retract in response to temperature change accordingly. For your specific application at different structures, go through the manual guide from the Cable Tray Institute.
A number of factors contribute to implementing the spacing for cable tray supports. Namely the material of the cable tray, highest and lowest temperatures, the rooftop will experience during operation and the specific temperature at the time of tray support installation. The cable tray support must be located ideally at more than 2 feet from each side of the expansion joint splice plate position, which in turn allows the cable tray to expand without distortion. It is beneficial to be anchored at the support closest to the midpoint to allow trays to expand and contract in response to temperature shifts.
As per industry requirements and specific on-field requirements cable tray systems are decided and installed at the location. Every application needs a unique setup procedure and working methodology. Different Types of Cable Trays are available in the market to choose from as per the customer needs. Cable trays are not just made to support all types of line. One should choose the application for installation accordingly. Water and compressed air tubing, for instance, cannot be supported by cable tray systems. According to the Cable Tray Institute, “NEC section 300.8 does not permit any tube, pipe, or equal for water, air gas, drainage, steam, or any service other than electrical in raceways or cable trays containing electrical conductors.” The main purpose of them are meant only to support power, signal, communication and optical fiber cables only. Also, there are NEC rules stating how each of these cable types must be segregated, either using the dividers within the tray or by separate trays units this can be achieved. Additionally, it helps reduce noise levels and interference from other cables.
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