By TEBAOFLEX Jyen. Originally published on June 27, 2026.
Construction is not a complete fire rating
Mineral-insulated metal-sheathed cable uses inorganic insulation within a metallic sheath. General wiring MIMS cable and specialist high-temperature heater or instrumentation cable are not automatically the same product. IEC 60702-1 covers specified mineral-insulated general wiring cables with copper or copper-alloy sheaths and copper conductors at its stated voltage ratings.
BS 7846 addresses armoured fire-resistant power cable constructions. A product can combine polymeric insulation with a fire-resistant barrier and achieve specified fire-test performance. Comparing only the ordinary insulation material misses the purpose of the complete construction.
Do not merge different test labels
CWZ refers to BS 6387 test categories. BS 8491 uses a different fire, mechanical shock and water test regime for the relevant cable scope. BS 7846 F120 is not simply another spelling of CWZ, and a PH120 result from another test does not automatically demonstrate the same performance.
The cited Prysmian FP600s documentation lists its BS 7846 F120 construction and separate BS 8491 and BS 6387 evidence. This is an example of how a manufacturer documents distinct requirements, not evidence of approval for a TEBAOFLEX cable.
Request the exact test method, duration, cable size range, mounting, electrical loading and failure criterion required by the project. A high flame temperature printed in a brochure is not a continuous operating-temperature rating.
The circuit includes supports and terminations
A cable that survives a laboratory test can still lose function if an unsupported span falls, a joint fails or a termination is unsuitable. Select supports, glands, joints and route protection as part of the emergency circuit design.
Whether a metallic sheath can serve a protective-conductor function depends on the applicable design, continuity, fault current, disconnection requirements and approved terminations. Do not omit a protective conductor solely because the cable has a copper sheath.
Electrical sizing under fire needs a valid basis
Normal current capacity, voltage drop and fault protection remain necessary. Emergency starting and running conditions may add requirements, including increased conductor resistance during exposure. The equipment voltage must remain within its permitted range.
Do not apply a room-temperature linear resistance coefficient up to an arbitrary 950 °C conductor temperature and claim guaranteed motor operation. Flame temperature is not necessarily conductor temperature, and the actual thermal history, cable construction and loading matter. Use the relevant engineering method and qualification evidence.
Moisture, handling and acceptance
Mineral insulation and terminations need appropriate moisture control. Use the manufacturer procedure for cutting, sealing, bending and insulation-resistance checks. Improvised flame drying can damage components or create hazards and is not a general repair instruction.
Provide the required circuit survival category, voltage, load, route, support system and environmental exposure. Keep traceable test and installation records. Neither an unconditional 50-year life nor any proprietary fire-survival result is claimed here.
Primary references and specification evidence
The references explain the cited technology or manufacturer example. They are not TEBAOFLEX product approvals or evidence that a supplied batch has passed the tests. Request the exact product drawing, specification edition, acceptance criteria and traceable records.
Discuss your application
Discuss the duty, installation and required documentary evidence with TEBAOFLEX. WhatsApp: +86 185 9591 3361. Product suitability and test obligations must be confirmed for the specific order.