BTTRZ 0.6/1kV 4x50mm²+1x25mm² Fire-resistant Cable for Industrial Emergency Feeders

Trading Properties

moq

100 meters

payment method

L/C,T/T

supply capacity

100000 meters per month

Product Summary

BTTRZ 0.6/1kV 4x50mm²+1x25mm² Fire-resistant Cable for Industrial Emergency Feeders BTTRZ 0.6/1kV 4×50 mm² + 1×25 mm² Flexible Mineral Insulated Fire-Resistant Cable Model note: BTTRZ is the Chinese enterprise-standard designation for a copper-conductor, mica-tape mineral insulated, corrugated ...

Product Details

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bttrz fire resistant cable

bttrz fire substation cable

1kv fire resistant cable

Conductor:

Class 2 Stranded Oxygen-free Copper (Cu-OF), 50 Mm² = 19/1.78 Mm, 25 Mm² = 7/2.14 Mm; Annealed, Flexible Stranding

Mineral Insulation:

Synthetic Mica Tape (muscovite/phlogopite) Lapped Around Each Conductor, Total Equiv. Thickness ~1.4 Mm On 50 Mm² / ~1.2 Mm On 25 Mm²; Inorganic, Non-combustible, 1000 °C+ Stable

Core Separation / Fill:

Glass-fiber Rope + Mineral Filler To Round Up The 5-core Bundle

Metallic Sheath:

Longitudinal Argon-arc Welded + Corrugated (rolled) Copper Tube

Optional Inner Bedding:

Thin Fire-resistant Glass-fabric Tape Over Corrugated Sheath

Outer Sheath:

WDZ Low-smoke Zero-halogen Polyolefin

Conductor DC resistance @ 20 °C:

50 Mm² ≤ 0.387 Ω/km · 25 Mm² ≤ 0.727 Ω/km

Short-circuit temp (5 s):

250 °C (max)

Continuous conductor temp:

90 °C Normal · 250 °C Short-circuit (5 S)

Ambient / laying temp:

−20 °C To +45 °C Ambient · Lay ≥ 0 °C (warm If Below)

Correction:

×0.91 At 35 °C, ×0.82 At 40 °C, ×0.71 At 50 °C Ambient.

Fire & circuit-integrity:

C — 950 °C Flame, 180 Min/W — 650 °C Flame 15 Min + Water Spray 15 Min/Z — 950 °C Flame + Mechanical Shock/impact 15 Min

Product Description

BTTRZ 0.6/1kV 4x50mm²+1x25mm² Fire-resistant Cable for Industrial Emergency Feeders

BTTRZ 0.6/1kV 4×50 mm² + 1×25 mm² Flexible Mineral Insulated Fire-Resistant Cable

Model note: BTTRZ is the Chinese enterprise-standard designation for a copper-conductor, mica-tape mineral insulated, corrugated (rolled) copper-sheath flexible fireproof cable. Equivalent IEC/GB family names: YTTW / RTTZ / BTTW. This 4×50+1×25 mm² size is a 5-core 3P+N+PE configuration (4 phase/line cores of 50 mm² + 1 reduced protective-earth core of 25 mm²).

1. Identification & Standards

Item	Specification
Model	BTTRZ-0.6/1kV 4×50+1×25 (also marked YTTW / RTTZ 4×50+1×25)
Product Name	Copper Core Flexible Mineral-Insulated Corrugated Copper-Sheathed Fire-Resistant Power Cable
Rated Voltage U₀/U	0.6/1 kV
Max. System Voltage Uₘ	1.2 kV
Core Configuration	4 × 50 mm² (L1/L2/L3/N) + 1 × 25 mm² (PE) — 5-core
Standards	GB/T 34926-2017 (China, equiv. to YTTW) · BS 6387:2013 (CWZ) · BS 8491:2008 · IEC 60331 · GB/T 19216 · GB/T 18380 (flame) · GB/T 17651 (smoke) · GB/T 19666 (LSZH)
Certification	CCC + type-test report from fire-research institute (BS 6387 CWZ grade)
Origin	Anhui / China general mfr base

2. Cable Construction (inside → outside)

Layer	Material & Detail
Conductor	Class 2 stranded oxygen-free copper (Cu-OF), 50 mm² = 19/1.78 mm, 25 mm² = 7/2.14 mm; annealed, flexible stranding
Mineral Insulation	Synthetic mica tape (muscovite/phlogopite) lapped around each conductor, total equiv. thickness ~1.4 mm on 50 mm² / ~1.2 mm on 25 mm²; inorganic, non-combustible, 1000 °C+ stable
Core Separation / Fill	Glass-fiber rope + mineral filler to round up the 5-core bundle
Metallic Sheath	Longitudinal argon-arc welded + corrugated (rolled) copper tube; acts as continuous moisture barrier, EMI screen, and functional PE (earth) conductor; nominal wall after corrugation ~1.3–1.4 mm
Optional Inner Bedding	Thin fire-resistant glass-fabric tape over corrugated sheath (on some brands)
Outer Sheath	WDZ low-smoke zero-halogen polyolefin (orange as standard, custom colors available); nominal thickness ~1.8–2.0 mm
Core Colors	50 mm²: Brown / Black / Grey / Blue (L1/L2/L3/N); 25 mm²: Green-Yellow (PE)

3. Key Dimensions & Physical Data (4×50+1×25)

Parameter	Typical Value	Remarks
Conductor DC resistance @ 20 °C	50 mm² ≤ 0.387 Ω/km · 25 mm² ≤ 0.727 Ω/km	GB/T 3956 Class 2
Approx. overall diameter	41.0 mm (typical) · range 38–44 mm by maker	Corrugated sheath adds ~2–3 mm vs. round
Approx. weight	5 200 kg/km (naked copper sheath) · ~2 990 kg/km with LSZH outer sheath (brand-dependent)	See ; wide spread due to sheath/thickness options
Min. bending radius	20 D (D = cable OD) → ≈ 820 mm	Per GB/T 34926 for D > 40 mm
IP rating (as installed)	IP40 bare / IP54 with sealed glands	Copper sheath itself is watertight
Short-circuit temp (5 s)	250 °C (max)	Normal 90 °C, mineral insulation allows higher short-term
Continuous conductor temp	90 °C normal · 250 °C short-circuit (5 s)
Ambient / laying temp	−20 °C to +45 °C ambient · lay ≥ 0 °C (warm if below)

BTTRZ 0.6/1kV 4x50mm²+1x25mm² Fire-resistant Cable for Industrial Emergency Feeders

4. Electrical & Fire Performance

4.1 Ampacity reference (PVC/XLPE-comparable baseline, 90 °C conductor)

In free air, single cable, 30 °C ambient: 50 mm² Cu ≈ 160–175 A per phase core; practical system rating for 4×50+1×25 BTTRZ ≈ 155 A (derated for 5-core mutual heating + mineral construction).
In conduit / trunking, 30 °C: ≈ 125–135 A.
Correction: ×0.91 at 35 °C, ×0.82 at 40 °C, ×0.71 at 50 °C ambient.
25 mm² PE core satisfies earth-fault loop requirements for upstream MCB/RCD up to 160 A frames.

4.2 Dielectric & insulation

Withstand test: 3.5 kV AC / 5 min (routine), no breakdown.
Insulation resistance: mica tape maintains >100 MΩ·km at 20 °C; >0.5 MΩ·km at 90 °C equivalent.
Partial discharge: none under normal service (inorganic lap insulation).

4.3 Fire & circuit-integrity (the core reason to specify BTTRZ)

Passes BS 6387 CWZ (highest grade) and GB/T 19216 / IEC 60331:

C — 950 °C flame, 180 min, circuit intact, no breakdown.
W — 650 °C flame 15 min + water spray 15 min, no breakdown.
Z — 950 °C flame + mechanical shock/impact 15 min, no breakdown.
Also complies with BS 8491:2008 large-diameter cable fire-survival test for smoke/heat control systems.
Flame retardant per IEC 60332-1 / GB/T 18380.1 (single cable self-extinguishing).
Smoke density: GB/T 17651 ≥ 60% light transmittance (LSZH version).
Halogen acid gas: IEC 60754-1/2 — essentially zero halogen, pH > 4.3, conductivity < 10 µS/mm.

5. Product Performance Summary

The BTTRZ 4×50+1×25 combines three properties that ordinary PVC/XLPE cables cannot deliver together:

True circuit integrity under fire — mica insulation + welded copper sheath keep power flowing to fire pumps, smoke fans, and emergency lighting while the building burns (950 °C, 3 h).
Flexible enough for real projects — corrugated copper sheath bends to 20 D, runs in trays, shafts, and conduits like a heavy PVC armoured cable; continuous length up to 500–1000 m with no intermediate joints required.
Copper sheath = built-in PE — the corrugated copper tube is connected to earth at both ends, giving a low-impedance protective conductor without a separate oversized green-yellow core; 25 mm² PE is code-acceptable as reduced earth for 50 mm² phases in fixed distribution per IEC 60364.

Additional traits: waterproof (seam-welded sheath), anti-termite/corrosion with LSZH jacket, electromagnetic shielding, 50-year design life, zero.

BTTRZ 0.6/1kV 4x50mm²+1x25mm² Fire-resistant Cable for Industrial Emergency Feeders

6. Application Scope

Primary use: fixed installation fire-safety power feeder and critical-load distribution where circuit must survive fire.

High-rise residential / commercial towers — riser feeders to fire-floor sub-boards
Hospitals, clinics, operating theatres — emergency power, nurse-call, life-support feeds
Metro / railway stations, airports, tunnels — smoke-extraction fan feeds, signal power
Data centers — UPS output to critical PDU rows, fire-suppression power
Hotels, malls, exhibition halls, libraries, museums — emergency lighting & PA power
Industrial plants — fire pump sets, deluge valve actuators, flammable-area distribution (Zone non-sparking due to metal sheath)
Underground car parks, generator transition boards, lift machine-room feeds

Not suitable for: direct burial without extra mechanical protection (use YJV22 instead), aggressive chemical soil without HDPE oversheath, repeated flexing/moving machinery (it is flexible for laying, not a flexing cord).

BTTRZ 0.6/1kV 4x50mm²+1x25mm² Fire-resistant Cable for Industrial Emergency Feeders

7. Installation Notes (4×50+1×25 specific)

Item	Practice
Bending	Use 20 D minimum (~820 mm). Use conduit sweeps; never sharp elbow.
Support	Cable tray: support every 600 mm horizontal, every 800 mm vertical. Weight ~3 t/km (LSZH) to ~5.2 t/km (bare) — calculate rack load.
Earth	Bond corrugated copper sheath to main earth bar at both ends with sheath clamp; 25 mm² green-yellow core also terminated to PE bar.
Termination	Use BTTRZ-specific fireproof seals / copper sheath glands (not standard PVC glands). Seal mica insulation with heat-shrink or ceramic cap to prevent moisture wicking into mica tape.
Pulling	Max pull ≈ 50 N/mm² × 200 mm² total Cu = 10 kN; use basket grip on sheath, not conductor.
Pre-commissioning	Megger 1000 V DC: L-PE, N-PE, L-L all ≥ 100 MΩ before energizing; check sheath continuity.

8. Selection Cross-Reference

Need	Better choice
Same fire grade, rigid, seamless sheath	BTTZ 4×50+1×25 (harder to bend, 6 D min)
Same flex fire cable, no LSZH jacket needed	RTTZ / YTTW (bare corrugated copper sheath, orange optional)
Fire grade + PVC-armoured economy	NG-A(BTLY) or YJV-0.6/1kV 4×50+1×25 + fire coating (lower integrity)
Higher current	BTTRZ 4×70+1×35 or 4×95+1×50
3-phase no separate N	BTTRZ 3×50+1×25 (4-core)

BTTRZ 0.6/1kV 4x50mm²+1x25mm² Fire-resistant Cable for Industrial Emergency Feeders

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