This article introduces four types of mineral insulated cables to colleagues in the industry, namely BTLY, BTMMRZ, BTTRZ and BTTZ. This article mainly introduces these four types of mineral insulated cables from two perspectives: inspection standards and product performance.
I. Introduction to (NG-A) BTLY
(1) Inspection Standard
After 180 minutes of flame exposure at 950±40℃, the line will not be broken down and the line power performance will remain intact. After 30 minutes of exposure at 650±40℃, the line power performance will remain intact after 15 minutes of water spray or immersion.
After 15 minutes of combustion test at 950±40℃, the line will remain intact after being hit and shaken without being damaged. The line meets the national requirements of BS 6387:2013 "Performance requirements for cables to maintain circuit integrity under fire conditions".
(2) Product Performance
Fireproof characteristics: BTLY cable strictly complies with the British BS6387 standard. In the event of a fire, it can guarantee at least 3 hours of precious time for necessary rescue of personnel and property.
Non-disaster-causing: BTLY cables offer strong overload protection and excellent resistance to high current surges. Even in the event of load changes or line short circuits, they will not catch fire like ordinary cables, resulting in no combustion or extended damage.
Flame-retardant: The primary material of BTLY cables (inorganic or inorganic compounds) makes them non-flammable, preventing them from spreading or spreading fire.
High current carrying capacity: To transmit the same current, BTTW cables can be 1-2 cross-sectional areas smaller than ordinary, flame-retardant, and fire-resistant cables.
High voltage rating: BTLY heavy-duty cables have a voltage rating of 1000 volts, higher than rigid mineral insulated cables.
Explosion-proof: BTLY cables can be manufactured to fixed lengths without intermediate joints, preventing flammable oil vapors, flammable gases, and flames from entering connected electrical equipment through the cables, providing explosion-proof protection.
Insulation: BTLY cables retain their shape above short-circuit temperatures, are highly fire-resistant, maintain a circuit continuity for three hours in a fire, and offer enhanced mechanical and chemical resistance, resulting in superior insulation performance.
High-Temperature Adaptability: While conventional cables typically operate at temperatures between 70°C and 90°C, BTLY cables can operate for extended periods at ambient temperatures up to 250°C, making them suitable for use in environments with specific requirements.
Waterproof: BTLY cables offer excellent resistance to water spray even in fire conditions.
High Mechanical Strength: BTLY cables are irradiated with high-energy beta electron beams, providing excellent resistance to mechanical impact.
Environmentally Friendly: While BTLY cables may generate a small amount of smoke-like vapor during a fire, this is harmless to the environment, eliminating the potential for smoke and toxicity that can cause serious health risks and secondary hazards associated with ordinary plastic cables during combustion.
2. Introduction to BTMMRZ
(1) Inspection Standard
While maintaining its softness, it greatly improves its fire resistance and can withstand 950℃ for 3 hours under 1000V working conditions. It also has the functions of anti-spraying and anti-mechanical impact.
(2) Product Performance
High temperature adaptability: The working temperature of ordinary cables is generally 70-90℃, while BBTRZ cables can work for a long time under the condition of ambient temperature of 125℃, so they can adapt to normal operation in some environments with specific requirements.
Waterproof properties: BBTRZ cables still have good water spray resistance under fire conditions.
High mechanical strength: The product has good mechanical impact resistance.
Environmental protection properties: Although BBTRZ cables may produce a small amount of water vapor similar to smoke under fire conditions, it is harmless to the environment and completely overcomes the "disaster" and "secondary disaster" caused by smoke and toxicity produced by ordinary plastic cables in flames.
Energy saving properties: With the same cross-sectional area, the reactive power loss of the cable will be greatly reduced, and long-term use will reduce a lot of energy waste. Easy installation: BBTRZ cable is suitable for various laying methods, and its structure is flexible and easy to bend. There is no joint in the middle and no special terminal is required, so there is no worry about accessories. General electrical personnel can lay it according to the conventional cable laying method.
III. Introduction to BTTRZ/BTLY-C
(1) Inspection standard
JG/T 313-2014 Standard of the Construction Industry of the People's Republic of China "Metal Sheathed Inorganic Mineral Insulated Cable and Terminals with Rated Voltage 0.6/1kV and Below".
Some unscrupulous manufacturers have used copper tape interlocking armor to counterfeit YTTW arc-welded threaded copper sheath. The interlocking armor is not a sealing process and is no different from ordinary steel tape armored cable. It only plays an external force protection role. The fatal point is that it is not waterproof and is very easy to be short-circuited due to moisture. It cannot pass the British standard BS 6387 spray fire test. The overall performance is worse than that of ordinary cables. Relevant units should be careful to avoid being deceived.
(2) Product Features
1 Excellent fire resistance, fire resistance level not only meets the national standard GB/T19216 21-2003 requires 1000°C for 180 minutes, and can also meet the C, W, and Z tests specified in British BS6387:2013 (fire resistance C-grade 950°C for 180 minutes, spray W-grade 650°C for 15 minutes, and impact Z-grade 950°C for 15 minutes).
2. Long continuous lengths. Whether single-core or multi-core cable, its length can meet power supply requirements, with each continuous length exceeding 1000m.
3. Large cross-section. Single-core cables can reach a cross-section of 630mm², and multi-core cables can reach a cross-section of 70mm².
4. Flexible, the cable can be wound on a reel with a bending radius of 6-10D (D is the cable's outer diameter).
5. Smokeless and non-toxic during combustion. The insulation is made of inorganic materials (non-combustible). No harmful gases are produced during combustion, and no secondary pollution occurs, making it an environmentally friendly green product.
6. High overload capacity. The cable not only has a high current carrying capacity but also a high overload capacity. According to wiring instructions, the cable surface temperature is usually ≤70°C. If the wiring is not touchable and does not come into contact with combustible building materials, the cable sheath temperature can be increased to 105°C. Fire-resistant cables can operate at temperatures up to 250°C under overload conditions.
7. Corrosion resistance. Organically insulated fire-resistant cables sometimes require plastic or iron conduits. Plastic conduits age and become brittle, while iron conduits rust easily. Fire-resistant cables, with their copper sheaths, do not require conduits, as the copper sheaths offer excellent corrosion resistance.
8. No electromagnetic interference. When laid in the same shaft as information and control lines, fire-resistant cables, shielded by the copper sheath, will not interfere with the information transmitted by the signal and control cables.
9. High safety. Fire-resistant cables can operate normally in flames, activate fire-fighting equipment, reduce fire damage, and provide exceptionally reliable protection for personnel. Their copper sheaths are excellent conductors, making them ideal for grounding (PE) conductors. They are continuous throughout the entire cable length, significantly improving the sensitivity and reliability of grounding protection.
10. Long service life. Inorganic insulation materials offer high temperature resistance and are not prone to aging, resulting in a lifespan many times longer than organically insulated cables. Under normal working conditions, its service life can reach more than 100 years;
11 The packaging, transportation, installation and accessories of flexible fireproof cables are similar to those of ordinary cables and are relatively simple;
12 Good economical performance. Due to its advanced manufacturing process and simple installation, the comprehensive cost of flexible fireproof cables is significantly lower than that of mineral insulated cables under the same conditions.
IV. Introduction to BTTZ
(1) Inspection standards
It has the characteristics of high temperature resistance, fireproof, explosion-proof, non-combustible (can operate continuously for a long time at 250℃, and can also operate for a short time of 30 minutes under the extreme state of 1000℃), large current carrying capacity, small outer diameter, high mechanical strength, long service life, and generally does not require an independent grounding wire.
(2) Product performance
1) Completely fireproof. BTTZ cables themselves do not burn at all and will not cause fire. Even in the case of flame roasting, as long as the flame temperature is lower than the melting point of copper, the cable can continue to be used without replacement after the flame is extinguished. No toxic smoke and gas will be generated when being roasted by flames. 2) Strong overload protection: When the line is overloaded, the cable will not be damaged as long as the heat does not reach the melting point of copper. Even if a momentary breakdown occurs, the magnesium oxide crystals at the breakdown point will not form carbides. After the overload is removed, the cable's performance will not change and it can continue to operate normally.
3) High operating temperature: Because the melting point of the magnesium oxide crystals in the insulation layer is much higher than that of copper, the cable's maximum normal operating temperature can reach 250°C. For short periods, it can continue to operate at temperatures close to the melting point of copper, 1083°C.
4) Excellent corrosion and explosion resistance: Because it uses a seamless copper tube as a sheath, BTTZ cables are resistant to water, moisture, oil, and some chemicals. The copper tube has considerable mechanical strength, providing excellent explosion resistance.
5) Long service life: Made entirely of inorganic materials, BTTZ cables are immune to insulation aging and can last more than three times longer than ordinary cables.
6) The laying flexibility is greater. BTTZ cables can be laid on the cable tray with ordinary cables, and can also be laid openly using special brackets. It is more flexible than laying ordinary cables, saves investment in cable trays, and can reduce the overall cost of the project.
