Introduction: Why Cable Code Designation Matters

Every cable manufactured to the Japanese Industrial Standard JIS C 3327 carries a code designation that functions as a compressed technical specification. When a crane manufacturer specifies a 2PNCT cable, or a port terminal engineer orders a 3PNCT replacement, the code itself communicates the cable’s flexibility class, insulation material, sheath material, and cable category—without requiring the engineer to look up a product catalogue. For anyone working with Japanese-standard cables—whether in port crane installations, ship unloader systems, industrial material handling, or general-purpose flexible power distribution—understanding this code system is a fundamental professional skill.

The JIS C 3327 designation system is elegant in its logic. Every cable name follows a predictable, parseable structure where each character or character group carries a specific, unambiguous meaning. Once you understand the five material symbols and the four flexibility classes, you can decode any of the 15 cable types defined by the standard—and immediately know what the cable is made of, how flexible it is, and what applications it is suited for.

This reference guide provides the complete decoding system for JIS C 3327 cable codes, with worked examples, a visual symbol dictionary, and a cross-reference to Feichun’s product range. Bookmark this page—it will save you time on every Japanese-standard cable specification you encounter.

The Four-Part Code Structure

Every JIS C 3327 cable code follows the same structural formula. The code is assembled from up to four parts, read left to right:

Part 1 — Class Number (1, 2, 3, or 4): A single digit at the beginning of the code that defines the cable’s flexibility classification. Class 1 is the least flexible; Class 4 is the most flexible. The class number is omitted only for the special case of silicone rubber cables (KKCT), which have a single class designation.

Part 2 — Insulation Material Code (optional letter): A single letter identifying the insulation material. If this letter is absent, the insulation is natural rubber (the default material in the original JIS standard). If present, it identifies a non-default insulation material: P for EP rubber, K for silicone rubber, etc.

Part 3 — Sheath Material Code (optional letter): A single letter identifying the outer sheath material. If absent, the sheath is natural rubber (default). If present, it identifies a non-default sheath material: R for chloroprene rubber (polychloroprene), H for polyethylene chlorosulfonide rubber, K for silicone rubber, etc.

Part 4 — CT (always present): The suffix CT appears at the end of every code. It stands for Cabtyre—the Japanese industrial term for a flexible cable designed for portable or dynamic applications. The CT suffix is the universal identifier that marks a cable as a JIS C 3327 flexible cable rather than a fixed-installation cable covered by other standards.

Symbol Dictionary: Every Letter Decoded

JIS C 3327 uses exactly six symbols to encode all cable information. Five are material codes and one is the cable category identifier:

Flexibility Classes: 1 Through 4

The class number prefix defines the cable’s conductor flexibility per IEC 60228 and JIS C 3327. Higher class numbers indicate finer conductor stranding and greater flexibility:

The class number has a direct impact on the cable’s mechanical performance. Class 2 conductors resist compressive deformation (ideal for drum winding) and maintain geometry under tensile load (ideal for long festoon spans). Class 3 provides good all-round flexibility for standard crane festoon applications. Class 4 offers the highest flexibility for applications requiring tight bending radii and extreme cycle life. Class 1 is rarely used in crane applications and is limited to fixed-installation scenarios.

Insulation Materials: The First Variable

The insulation material is the dielectric layer that separates the conductor from the cable’s metallic screen or sheath, providing electrical isolation at the rated voltage. JIS C 3327 defines four insulation material options:

For port crane and ship unloader applications, EP rubber (P) is the industry standard insulation choice. Its combination of high dielectric strength, wide operating temperature range (−30°C to +80°C), ozone resistance, and ability to withstand millions of flex cycles without cracking makes it the optimal insulation for any cable that will operate in a dynamic marine terminal environment. This is why PNCT-designated cables dominate the port crane market worldwide.

Sheath Materials: The Second Variable

The sheath (outer jacket) is the cable’s external protective layer, providing mechanical protection, environmental resistance, and—in some formulations—flame retardancy. JIS C 3327 defines four sheath material options:

For port crane applications, chloroprene rubber (R) is the dominant sheath choice. Its simultaneous oil resistance, flame retardancy, UV stability, saltwater impermeability, and mechanical toughness make it the only sheath material that can survive the multi-hazard port terminal environment without compromise. This is why PNCT (EP rubber insulation + chloroprene rubber sheath) is the standard specification for crane cables globally.

Complete Classification Table: All 15 Cable Types

Decoding Examples: Reading Any JIS C 3327 Cable Name

Example 1: 2PNCT

Translation: Class 2 flexibility, EP rubber insulation, chloroprene rubber sheath, flexible cable. This is the TRACAB® cable for curtain, carrier drum, and cableveyor transport systems on port cranes. Feichun equivalent: FC-2TC-RB-K™.

Example 2: 3PNCT

Translation: Class 3 flexibility, EP rubber insulation, chloroprene rubber sheath, flexible cable. The 6600V high voltage variant under JIS C 4353 is also designated 3PNCT. Feichun equivalent: FC-2PNCT-K™ (600V) or FC-3PNCT-6.6kV-K™ (6600V).

Example 3: 3CT

Translation: Class 3 flexibility, natural rubber insulation, natural rubber sheath, flexible cable. The basic general-purpose cabtyre cable. Suitable for indoor, dry, oil-free environments only—not recommended for port crane or marine terminal use.

Example 4: KKCT

Translation: Silicone rubber insulation, silicone rubber sheath, flexible cable. The extreme-temperature specialist: −60°C to +180°C operating range. Used in steelworks, glass manufacturing, foundries, and high-temperature industrial applications. Not typically used in port crane applications (limited oil resistance).

Example 5: 4PHCT

Translation: Class 4 (high) flexibility, EP rubber insulation, polyethylene chlorosulfonide rubber (Hypalon® type) sheath, flexible cable. The premium specification for chemical plants, nuclear facilities, and environments requiring exceptional chemical and UV resistance beyond what chloroprene can provide.

Extended Suffixes: SB, Light, RB & Voltage Prefixes

Beyond the core JIS C 3327 designation, cable manufacturers (including Feichun) use additional suffixes and prefixes to identify product variants within the same base specification. These extensions are not part of the JIS standard itself but are widely used in the industry:

The -SB suffix stands for Shielded Braided and indicates the cable includes a metallic braid shield (tinned copper combined with cotton yarn) for electromagnetic interference containment. This suffix is essential when specifying cables for VFD-driven crane motor applications.

The voltage prefix (600V or 6600V) is critically important: it determines not only the insulation thickness and test voltage but also the applicable standard. 600V cables are manufactured to JIS C 3327, while 6600V cables are manufactured to the separate standard JIS C 4353, which specifies additional requirements including semiconductive stress-grading layers, metallic earth screens, dual-layer sheaths, and partial discharge testing.

Feichun Product Cross-Reference

Anhui Feichun Special Cable Co., Ltd. manufactures Kevlar®-reinforced equivalents for the most widely used PNCT-family cables in port crane applications. The following table maps JIS designations to Feichun product codes:

All Feichun equivalents add Kevlar® para-aramid fibre braided tensile reinforcement—a feature not specified by the base JIS standard but essential for the dynamic mechanical demands of port crane festoon, reeling, and cableveyor applications. The Kevlar® layer provides 5× the tensile strength of steel per unit weight, absorbing self-weight catenary loads and dynamic forces without transferring mechanical stress to the conductors or insulation system.

Quick-Reference Decoding Chart

Cut out and keep—a single-glance reference for decoding any JIS C 3327 cable name: