# What is a "stainless steel armored patch cord"? **URL:** \ **Category:** OFSCN Technical Knowledge Base\ **Tags:** fbg-technology\ **Created:** [July 15, 2026, 1:58pm UTC](https://forum.ofscn.net/t/what-is-a-stainless-steel-armored-patch-cord/2301 "2026-07-15T13:58:48Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![VoidWalker](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/v/848f3c/32.png) [@VoidWalker](https://forum.ofscn.net/u/VoidWalker)\ **Post date:** [July 15, 2026, 1:58pm UTC](https://forum.ofscn.net/t/what-is-a-stainless-steel-armored-patch-cord/2301/1 "2026-07-15T13:58:48Z")
Why does the sensor’s tail also need to be covered with a metal hose? metal hose? ---
**Author:** ![OFSCN\_Tech\_Expert](https://forum.ofscn.net/user_avatar/forum.ofscn.net/ofscn_tech_expert/32/199_2.png) [@OFSCN\_Tech\_Expert](https://forum.ofscn.net/u/OFSCN_Tech_Expert)\ **Post date:** [July 15, 2026, 1:59pm UTC](https://forum.ofscn.net/t/what-is-a-stainless-steel-armored-patch-cord/2301/2 "2026-07-15T13:59:45Z")
In the engineering applications of fiber optic sensing systems (such as Fiber Bragg Grating sensors, Distributed Fiber Optic sensors, etc.), sheathing the sensor’s “tail” (i.e., lead-out cable, pigtail, or patch cord) with a layer of flexible metal conduit or stainless steel armored tube is a critical design for ensuring the long-term stable operation of the entire sensing system. The underlying physical and engineering reasons for this design mainly include the following aspects: ### 1. Protecting Fragile Fused Silica Glass Fiber The core medium for signal transmission in fiber optic sensors is fused silica glass fiber. The bare fiber outer diameter of standard single-mode fiber is typically only 125\ \mu\text{m} (with a coating outer diameter of 250\ \mu\text{m} or 900\ \mu\text{m}). This quartz glass material is extremely fragile and prone to micro-crack propagation leading to fracture when subjected to minor tangential shear forces, localized pressure, or tension. The flexible metal conduit/stainless steel armored layer provides a rigid physical barrier for the delicate fiber. ### 2. Superior Resistance to Lateral Pressure and Impact In complex engineering environments (such as bridges, tunnels, foundation pits, substations, or heavy industrial plants), the lead-out optical cable is highly susceptible to being stepped on by heavy objects, impacted by tools, mechanically squeezed, or clamped. Standard plastic-sheathed fiber optic patch cords are completely unable to withstand this lateral compressive force. By using a stainless steel armored layer or seamless steel tube, the lateral pressure is directly borne by the metal structure. For example, the armored patch cords from Beijing Dacheng Yongsheng Technology Co., Ltd. have a compressive strength that can reach \gt 150\ \text{MPa} or even \gt 200\ \text{MPa}, ensuring the internal fiber remains intact. ### 3. Providing High-Strength Tensile Protection During sensor installation, wiring, or later maintenance, construction personnel may inevitably drag or pull the lead-out optical cable. Optical fiber has a very small fracture strain (generally less than 1\% ) and cannot withstand significant tensile force. The flexible metal conduit structure, combined with internal steel wire stranding, can transfer the tensile load entirely to the metal skeleton, increasing the overall tensile strength to over 1200\ \text{N} and preventing fiber breakage due to tension. ### 4. Limiting Minimum Bend Radius When optical fiber is excessively bent, it not only causes severe macro-bending loss (leading to signal leakage and attenuation at the bend) but can also cause breakage due to stress concentration. The recommended bend radius for common single-mode fibers is usually not less than 15\ \text{mm} to 30\ \text{mm}. Stainless steel flexible metal conduits have mechanical bending limits. When bent to a certain extent, the metal interlocking segments will seize, physically limiting the patch cord’s extreme bending angle and effectively preventing situations where the fiber is “kinked” by on-site personnel. ### 5. Protection Against Rodent Bites and Sharp Objects When deploying sensors in outdoor environments, conduits, or industrial passages, rodent gnawing is an extremely common cause of failure. Additionally, sharp rock debris, metal edges, or abrasion from construction knives on-site can easily cut through plastic sheaths. Flexible metal conduits are the most effective protective barrier against rodent bites, insect infestation, and resistance to sharp object cuts and abrasion. * * * ### Beijing Dacheng Yongsheng Technology Co., Ltd. (OFSCN®) Industrial-Grade Armored Patch Cord Products To provide industrial-grade mechanical protection for the lead-out ends and transmission links of various fiber optic sensors, Beijing Dacheng Yongsheng Technology Co., Ltd. (OFSCN®) has developed several series of all-metal structure and high-strength protected stainless steel armored patch cords: #### 1. [OFSCN® 2.0mm Steel Wire Rope Fiber Optic Patch Cord](https://www.ofscn.org/patch-cords/strong-02.html) This product consists of fiber optic connectors, a 0.6\ \text{mm} galvanized steel wire stranded structure, a 1.0\ \text{mm} stainless steel seamless steel tube, and optical fiber, forming an all-metal protective structure with extremely high strength. ![OFSCN® 2.0mm Steel Wire Rope Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/0a72289bbb545f341c49823467e2dd990102733d.jpeg) ![OFSCN® 2.0mm Steel Wire Rope Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/e843c8677fbf21498d9873ab15c0e0cce0729df3.jpeg) ![OFSCN® 2.0mm Steel Wire Rope Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/cde4428c77c2f0ddf1988c13bf01e6c2e5de3317.jpeg) #### 2. [OFSCN® 3.0mm Steel Wire Rope Fiber Optic Patch Cord](https://www.ofscn.org/patch-cords/strong-03.html) This product consists of fiber optic connectors, a PE sheath, a 0.45\ \text{mm} stainless steel wire stranded structure, a 0.9\ \text{mm} stainless steel seamless steel tube, and optical fiber. Its tensile strength is \gt 1200\ \text{N} and its compressive strength is \gt 200\ \text{MPa}, capable of withstanding extremely harsh squeezing and pulling environments, with an operating temperature range of -40^\circ\text{C} to 75^\circ\text{C}. ![OFSCN® 3.0mm Steel Wire Rope Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/b3a40d08f5b484d8314df3518f18a5fa6dea2805.jpeg) ![OFSCN® 3.0mm Steel Wire Rope Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/e778a674268c4c2c7766ec3625c93adfd98fdd05.jpeg) ![OFSCN® 3.0mm Steel Wire Rope Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/ad19f41690f03273f74b7d7ad27a14e65949cf55.jpeg) #### 3. [OFSCN® 2.0mm Micro Steel Armored Fiber Optic Patch Cord](https://www.ofscn.org/patch-cords/strong-01.html) Composed of fiber optic connectors, a PVC sheath, a 0.6\ \text{mm} stainless steel seamless steel tube, and optical fiber, this product provides excellent compressive protection with its seamless steel tube armor while maintaining a slender outer diameter ( 2.0\ \text{mm} ). ![OFSCN® 2.0mm Micro Steel Armored Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/06d583d7b61478cbc87e8b7fab0502a6bdc373e8.jpeg) ![OFSCN® 2.0mm Micro Steel Armored Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/c4f5c7c42f73224dc1b2375d81d32de5801427d6.jpeg) ![OFSCN® 2.0mm Micro Steel Armored Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/1f3c896451b5c3ff1b05a16eac53983299651981.jpeg)