China Zhenglan Cable Technology Co., Ltd Company News

Fire-resistant electrical wires are crucial. In case of fire, critical systems like alarms, smoke extraction, and emergency lighting all depend on them – they are truly a "lifeline." But how do you choose the right fire-resistant wires? Actually, just remember these four types, and you too can become an expert! What types of fire-resistant wires are there? According to the "General Principles for Flame-Retardant and Fire-Resistant Wires and Cables," fire-resistant wires are mainly divided into the following four types: Flame-retardant cables (ZR): If these cables encounter fire, they won't burn immediately, but will burn slowly. Once the fire is extinguished, they will stop burning themselves, preventing the fire from spreading further. They are suitable for general fire safety equipment, such as manual alarm buttons. Fire-resistant cables (NH): These can withstand high temperatures of 750℃ and can continuously supply power for 90 minutes. Their insulation layer uses mica tape, which is particularly heat-resistant. Equipment that is particularly important during a fire, such as smoke exhaust fans, fire pumps, and emergency lighting, requires this type of cable. Mineral insulated cables (BTTZ): These have a copper core and magnesium oxide insulation. Their advantage is that they can withstand high temperatures of 950℃ and are also waterproof and explosion-proof. They are essential for ensuring power supply safety in places with extremely high safety requirements, such as super high-rise buildings, tunnels, and nuclear power plants. Halogen-free low-smoke cables (WD): When these cables burn, they produce very little smoke and no toxic gases. According to the standard, the light transmittance can reach over 60%. Therefore, they are safer in densely populated areas such as subways, hospitals, and schools, reducing the harm caused by smoke and toxic gases during a fire. 5 tips for choosing fire-resistant wires: Consider the building type: For super high-rise buildings or underground projects, mineral insulated cables (BTTZ) are a must, as only they can guarantee stable power supply in such extremely complex and dangerous environments. For ordinary commercial buildings, it's best to use a combination of fire-resistant (NH) and halogen-free low-smoke (WD) cables. This ensures both safety and meets practical needs. Select based on system importance: For critical equipment like fire pumps and smoke exhaust fans, which play a crucial role in fire fighting, mineral insulated cables must be used, as their stable operation is vital to the success of the entire fire protection system. For secondary load equipment like emergency lighting, fire-resistant (NH) cables are sufficient and more cost-effective. Choose based on the installation environment: If installed in damp places, such as basements or swimming pools, cross-linked polyethylene insulated (YJV) cables should be used, and the waterproof rating must be IP67 or higher to prevent water from affecting the cable's normal operation. In corrosive environments, such as near chemical plants, armored cables like NH-YJV22 should be used, as their outer sheath can resist corrosive substances such as acids and alkalis. Consider cost: If you want to save money, use flame-retardant cables (ZR) and supplement them with fire-resistant cables (NH) in critical areas. This ensures basic safety while controlling costs. If you prioritize extremely high reliability and don't mind spending more, use mineral insulated cables (BTTZ) throughout the entire system, although this will increase costs by approximately 30% to 50%. Follow regulations: If fire protection power lines are laid openly, they must be routed through metal conduits or enclosed metal trunking and coated with fire-retardant paint to further enhance fire safety. How to check the quality after selection: Check certificates: When purchasing cables, the supplier should provide a third-party test report containing key data such as fire resistance time and smoke density. This report confirms whether the cable meets the standards. Test performance: Samples can be sent to a professional institution for testing.  The insulation resistance should be tested, and it must be above 20MΩ.  Fire resistance should also be thoroughly tested to determine the actual quality of the cable. Inspection of markings:  Legitimate cables will have clear markings such as "NH" and "WD" printed on the outer sheath, indicating the cable type. These markings should be clear and not easily rubbed off. If the markings are unclear or easily erased, the cable is likely defective. Future trends in fire-resistant cables: Flexible mineral-insulated cables: These cables may gradually replace traditional BTTZ cables in the future because they have a smaller bending radius, making installation easier and increasing construction efficiency by 50%. This will save considerable time and labor costs. Intelligent monitoring cables: These cables are equipped with temperature sensors. If the line temperature becomes too high, an alarm will be triggered immediately, allowing for early detection of potential hazards and preventing fires. This is particularly helpful for fire safety. Environmentally friendly materials: According to industry forecasts for 2025, the proportion of halogen-free, low-smoke cables will increase to 80%.  More and more places will use these more environmentally friendly and safer cables in the future, reducing the harm to the environment and people during fires.

Polyethylene (PE)Characteristics: Polyethylene is divided into low-density (LDPE), medium-density (MDPE), and high-density (HDPE). It has excellent low-temperature resistance (remaining flexible at -60°C), excellent chemical resistance, low water absorption, and good electrical insulation properties. HDPE also has high strength and excellent weather resistance.Advantages:Suitable for outdoor, buried, submarine, and high-altitude environments, such as communication cables, fiber optic cables, and offshore wind power cables.Environmentally friendly and recyclable, with minimal environmental impact.MDPE and HDPE, after carbon black stabilization treatment, have outstanding UV resistance and are suitable for long-term exposure to sunlight.Limitations: Untreated PE is flammable and has poor flame retardancy, so it is not recommended for indoor locations with high fire safety requirements.Low Smoke Zero Halogen (LSZH/LSOH)Characteristics: LSZH (Low Smoke Zero Halogen) materials are usually based on polyolefins, with aluminum hydroxide or magnesium hydroxide added as flame retardants.  They produce extremely low smoke concentrations during combustion and do not release halogen-containing toxic gases.Advantages:High safety: Designed for densely populated or enclosed spaces, such as subways, tunnels, data centers, hospitals, high-rise buildings, and public transportation systems.Minimal corrosive gas emissions during combustion, reducing secondary damage to equipment and personnel.Complies with modern building and industrial safety standards, and is an environmentally friendly upgrade alternative to PVC.Limitations: Higher production costs than PVC and PE, and more complex processing technology, resulting in higher cable prices.Polyvinyl Chloride (PVC)Characteristics: PVC is one of the most widely used sheath materials, with low cost, good flexibility, acid and alkali resistance, and a certain degree of flame retardancy.Advantages:Economical and practical: High cost-effectiveness, easy to process, suitable for indoor wiring, low-voltage power cables, and general industrial cables.Good mechanical protection and insulation performance, suitable for fixed installation in general environments. Limitations:It softens easily at high temperatures (the typical long-term operating temperature does not exceed 80°C), and may become brittle at low temperatures.It contains halogens, and when burned, it produces a large amount of dense smoke and toxic gases such as hydrogen chloride, which does not meet the high safety standards of modern buildings.It is not suitable for places with strict requirements for environmental protection and smoke toxicity.

10kV high-voltage switchgear includes: 10kV high-voltage outgoing switchgear, 10kV high-voltage incoming switchgear, 10kV high-voltage ring main unit, PT cabinet, and metering cabinet. The terms "incoming switchgear" and "outgoing switchgear" differ by only one character; their differences and functions are significant. Incoming switchgear – This is the switchgear that receives power from an external source. Generally, it receives 10kV power from the power grid. This 10kV power is then transmitted to the 10kV busbar through the switchgear; this switchgear is the incoming switchgear. In substations with voltage levels of 35-110kV and above, the incoming switchgear refers to the transformer's low-voltage (10kV) switchgear. That is, the first cabinet connecting the low-voltage output of the transformer to the initial terminal of the 10kV busbar is called the incoming switchgear, also known as the transformer's low-voltage incoming switchgear. The incoming line switchgear is the main switchgear on the load side. This switchgear bears the current carried by the entire busbar. Because it connects the main transformer to the low-voltage side load output, its role is crucial. In terms of relay protection, when a fault occurs on the low-voltage side busbar or circuit breaker of the main transformer, the overcurrent protection on the low-voltage side of the transformer trips the incoming line switchgear to clear the fault. A fault on the low-voltage side busbar also relies on the backup protection on the low-voltage side of the main transformer to clear the incoming line switchgear. The transformer differential protection also clears the low-voltage side circuit breaker, i.e., the incoming line switchgear. In a 110kV substation, the switch parameters for the low-voltage incoming line switchgear differ from those of other switchgear. Its rated current is 3150A～4000A, and its rated breaking current is 31.5～40kA. The parameters of the 10kV bus tie switchgear are the same as those of the incoming line switchgear. Outgoing line switchgear—this is the switchgear that distributes electrical energy from the busbar. Power is transmitted from the 10kV busbar to the power transformer via a switchgear; this switchgear is one of the 10kV outgoing switchgear units. An outgoing switchgear is installed on the low-voltage side of the transformer, transmitting power through this switchgear to the low-voltage busbar. Several other low-voltage switchgear units are then installed on the low-voltage side to distribute power to various points of use. These low-voltage switchgear units are all outgoing switchgear units. If a low-voltage system is introduced from nearby, the low-voltage switchgear connected to the incoming line is also an incoming switchgear unit, only at a lower voltage. Switchgear units extending from the low-voltage busbar are also outgoing switchgear units. Therefore, incoming switchgear units can be high-voltage or low-voltage, and similarly, outgoing switchgear units can be high-voltage or low-voltage.

Dear Customers Thank you so much for your accopmay in the past days. Here comes the new year 2026. We sincerely send you our greetings. Hope you and your family peaceful, happy, healthy. Hope you will have more progess in your work or business. Happy new year!! We will be on a 3-day legal holiday from January 1st to 3rd. During holiday we may have limit access to email. If you have any inquiry, we will get back to you once resume work.  Zhenglan Cable Technology Co., Ltd 2025.12.31

Different countries have their own cable nomenclature, generally with a combination of alphanumeric descriptions which together build up a designation which clearly defines the voltage rating and materials employed. Below are Medium Voltage cables esignation  in Portugal. X Copper Conductor LX  Aluminium Conductor HI Metallic Screen - Copper Tape HIO Metallic Screen - Copper Wires  R Steel wire armour (for multi-core cables) A Steel tape armour (for multi-core cables) 1R / 1A Aluminium armour/aluminum tape armour (for single core cables) L Longitudinal waterblocking tape XS 3x1 core with messenger wire with XLPE sheath E Polyethylene (PE) Outer Sheath V Polyvinyl Chloride (PVC) Outer Sheath Z1 Polyolefin Outer Sheath DMZ1 or DMZ2 for Low Smoke Halogen-free cables  (ce) Longitudinal water tightness in conductor (be) Longitudinal water tightness in metallic screen (cbe) Longitudinal water tightness in conductor and metallic screen flr Minimum CPR Classification Eca frt Minimum CPR classification Cca s1b, d1, a1

Irradiation cross-linking, also known as electron beam cross-linking, involves using high-energy electron beams generated by electron accelerators to break and rebuild the molecular bonds within the insulation and sheath layers of cables. When high-energy electron beams penetrate materials such as polyolefins, they act like countless molecular scalpels, simultaneously cutting all the weak links in the original molecular chains and then re-welding them into a dense three-dimensional network structure. This process gives the raw materials unique properties such as temperature resistance, acid resistance, radiation resistance, high flame retardancy, and high toughness. Irradiation cross-linked flame-retardant wires and cables are primarily used in fire-sensitive areas such as homes, multi-story buildings, hotels, hospitals, subways, nuclear power plants, tunnels, power plants, mines, oil and chemical plants, as well as in power supply lines for emergency equipment such as fire alarm systems, security equipment, smoke exhaust systems, emergency escape routes, and lighting. The advantages of electron beam irradiation of cross-linked wires and cables include: 1. Irradiation cross-linked products offer high performance, energy efficiency, and zero pollution;2. Irradiation cross-linking is a method that can produce wires and cables that are both chemically cross-linked and flame-retardant.3. High temperature resistance. Irradiation cross-linked products can withstand temperatures of 105-150℃, while other chemical cross-linking methods are currently limited to 90℃, and PVC is only 70℃.4. Strong radiation resistance (good aging and thermal embrittlement resistance), and excellent crack resistance;5. Irradiation products are cross-linked at room temperature, preventing conductor annealing and defects caused by thermal stress during the production process, and avoiding thermal stress on the insulation layer. Future development trends show continuous progress in technological innovation for irradiated cables. For example, dynamic electron beam control technology, high-energy electron beam irradiation technology, and double-layer co-extrusion processes have not only further improved the durability and safety of wires but also made the production process more environmentally friendly. In the future, with continuous technological advancements, irradiated cables are expected to be applied in more fields, such as smart grids and efficient energy management systems, opening up broader market prospects.