What are the common models of fire-resistant cables?

Fire‑resistant cables can be broadly divided into two types: flexible mineral‑insulated fire‑resistant cables and rigid mineral‑insulated fire‑resistant cables. So, what are the various models of flexible fire‑resistant cables and rigid fire‑resistant cables?

Among fire‑resistant cables, the common models include BTTZ, BTTRZ (RTTZ), BBTRZ, NG‑A (BTLY), YTTW, and BTTVZ. Among these, only cables under the BTTZ category are rigid mineral‑insulated fire‑resistant cables; the others are all flexible mineral‑insulated fire‑resistant cables.

1. BTTZ cable, fully known as Heavy‑Duty Copper‑Core Copper‑Sheathed Magnesium Oxide Mineral Insulated Cable, boasts high temperature resistance, fire retardancy, explosion protection, and non‑combustibility (it can operate continuously for extended periods at 250°C and can withstand short‑term operation for up to 30 minutes even under extreme conditions of 1000°C). It also features high current-carrying capacity, a small outer diameter, high mechanical strength, and a long service life, generally eliminating the need for separate grounding conductors.

The letter abbreviations for BTTZ fire-resistant cables are as follows:

B—Power cables for fixed installation used in wiring

T—Copper Sheath

T—Copper Conductor

Z—Heavy-duty 750V voltage rating

As a rigid cable, BTTZ boasts features such as complete fire resistance, strong overload protection, high operating temperatures, corrosion resistance, and long service life, making it ideal for use as a fire‑resistant cable in fire protection systems within construction projects.

2. BTTRZ (RTTZ) cable, fully known as copper‑core inorganic mineral‑insulated, tape‑wrapped insulated, copper‑sheathed flexible fire‑resistant cable, is referred to as a mineral‑insulated cable and also as a fire‑resistant cable with a flexible structure. Its manufacturing process is very similar to that of BTTZ cables. This type of cable boasts both flexibility and flame retardancy, exhibits excellent bending performance, is highly convenient for transportation, and offers reliable performance in use.

The letter meanings for BTTRZ (RTTZ) fire-resistant cables are as follows:

B—Power cables for fixed installation used in wiring

T—Copper Conductor

T—Copper Sheath

R—Softness

Z—Heavy-duty 750V voltage rating

The difference between BTTRZ and BTTZ lies in the fact that BTTRZ is a flexible fire‑resistant cable. BTTRZ can replace BTTZ; the former is a flame‑retardant copper‑core wiring cable, while the latter is not flame‑retardant. Both cables use the same production process, but they employ different insulation materials—and today, the former is used more frequently.

3. BTTVZ stands for “Belt-Through-Terminal-Voltage-Zero” and refers to a heavy-duty copper-core, copper-sheathed magnesium oxide mineral-insulated cable. Because all of the materials used in this type of cable are inorganic, it boasts several advantages that other cables simply cannot offer—such as fire resistance, high current-carrying capacity, resistance to mechanical damage, halogen‑free and non‑toxic properties, explosion protection, water resistance, corrosion resistance, long service life, overload tolerance, high‑temperature resistance, low cost, and a small outer diameter.

B----Power cables for fixed installation used in wiring

T----Copper Sheath

T----Copper Conductor

V----Polyethylene Y Outer Sheath

Z----Voltage Withstand Option: Heavy-duty voltage rating 750V, light-duty voltage rating 500V

4. BBTRZ stands for Flexible Magnesium Hydroxide Mineral Insulated, Non‑Combustible Fire‑Resistant Cable. The structure of flexible mineral insulated cables employs a flexible design and is constructed entirely from mineral compounds, thereby overcoming the drawbacks of rigid structures—such as flammability and toxicity. These cables also boast several advantages that are impossible to achieve with other types of cables, including: fire resistance, high current-carrying capacity, resistance to impulse voltages, tolerance to mechanical damage, halogen‑free and non‑toxic properties, explosion protection, water resistance, corrosion resistance, long service life, overload resistance, high‑temperature resistance, and low cost.

The letter meanings for BBTRZ fire-resistant cables are as follows:

B—Power cables for fixed installation used in wiring

B—Mineral Compounds

T—Copper Conductor

R—Softness

Z—Heavy-duty 750V voltage rating

5. NG-A (BTLY) — its full name is Aluminum-Sheathed Flexible Isolation Fire-Resistant Cable. The NG-A cable features a soft conductor structure that has been specially processed to deliver excellent electrical conductivity, mechanical strength, flexible bending performance, and superior fire resistance. It is densely filled with mineral materials, providing high-temperature resistance and outstanding fire‑proofing capabilities. The outer sheath is made from low‑smoke, low‑halogen plastic materials, offering excellent corrosion‑resistance properties.

The letter abbreviations for NG-A (BTLY) fire-resistant cables are as follows:

G----Isolation

N----Fire‑resistant

A----950–1000°C

B----Mineral‑insulated cable for wiring

T----Copper Conductor

L----Aluminum Metal Sleeve

Y----Polyvinyl Chloride Outer Sheath

6. The full name of YTTW cable is Flexible Fire-Resistant Metal-Sheathed Inorganic Mineral Insulated Cable. A fire‑resistant cable is a type of cable that can continue to conduct electricity normally for more than three hours even when exposed to high temperatures of 950°C. It is primarily composed of an outer sheath and copper conductor cores, with a fire‑resistant layer embedded within the outer sheath, giving it exceptional fire‑resistance performance.

The letter meanings for YTTW fire-resistant cables are as follows:

Y—Mica Tape–Metal Sheath Mineral‑Insulated Cable

T—Copper Conductor

T—Copper Sheath

W—Inorganic Mineral Insulation

Having reached this point, we’ve summarized the common models of fire‑resistant cables. We hope that after reading this, you now have a better understanding of fire‑resistant cables. Fire‑resistant cables are already used in a wide range of applications, and there are also fire‑proof cables and flame‑retardant cables—cable models are highly diverse, so it’s crucial that we can distinguish between them.