What is a mineral-insulated cable?-Guangdong Yongyi Zhujiang Wire & Cable Co., Ltd. – A manufacturing enterprise specializing in the production of wires and cables.

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What is a mineral-insulated cable?

2020-01-03

The BTTZ series mineral-insulated cables, known internationally as Mineral Insulated Cables, are referred to domestically simply as mineral-insulated cables or mineral-insulated non-combustible cables.

It is currently the only internationally recognized mineral-insulated cable. It features solid copper conductors with high electrical conductivity as the core, highly compressed powdered magnesium oxide (MgO) as the insulation, and a seamless copper sheath—all manufactured using specialized processes to create wiring cables for modern buildings as well as cables tailored for specific industries (such as metallurgy, chemical engineering, and petroleum).

Due to the special nature of its materials and structure, this product boasts electrical performance, mechanical performance, environmental resistance, and eco-friendly characteristics that are unmatched by conventional organic cables (plastic cables). This unique structure ensures that the melting points of the conductor and insulation materials are 1083°C and 2800°C, respectively. As a result, under fire conditions, the cable allows equipment to continue operating safely at temperatures exceeding 1000°C.

What are rigid and flexible mineral-insulated cables?

For a long time, domestically produced mineral-insulated cables have been broadly categorized into two main types—rigid and flexible—based on their insulation materials. This classification stems from the fact that the internationally recognized magnesium oxide–insulated mineral-insulated cable (IEC 60702-1:2002) uses solid conductors of Type 1 as specified in IEC 60228; these conductors differ from the stranded or flexible conductors commonly found in conventional cables. Later, China pioneered the development of the JG/T 313 standard YTTW series metal-sheathed inorganic mineral-insulated cables, the GB/T 34926 standard RTTZ series mica-band mineral-insulated corrugated copper-sheathed cables, and a range of enterprise-specific standards for mica-band mineral-insulated cables that do not employ solid conductors. All these cables have been collectively—and somewhat loosely—classified by industry insiders as “flexible mineral-insulated cables,” solely to distinguish them from magnesium oxide–insulated mineral-insulated cables. Thus, the so-called “flexible mineral-insulated cables” are merely somewhat softer than magnesium oxide–insulated mineral-insulated cables. They should not be mistakenly interpreted as having the fine-strand soft conductors traditionally associated with flexibility; in reality, they are neither truly rigid nor genuinely flexible.

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Analysis of the Selection and Development Trends of Mineral-Insulated Cables for Fire Protection Circuits