Chinese Cable Type Codes Explained: YJV, VV, KVV, DJYPVP...

The code is built in blocks, not at random

Every type code in the GB/T 12706 and JB/T 8734 families follows the same logic. Reading from left to right, the first letters describe the insulation and, if it is not copper, the conductor. Any prefix before that describes the fire performance. The digits at the end describe the armour and then the outer sheath. Nothing else is hidden in the code: the voltage rating, the number of cores and the cross-section are always written separately, as 0.6/1 kV and 4 × 95, because they are not part of the type.

Take YJV22 as the worked example. YJ is XLPE insulation. The absence of a conductor letter means copper. The first 2 is double steel tape armour. The second 2 is a PVC outer sheath. So YJV22 is an XLPE insulated, copper, steel tape armoured, PVC sheathed cable, and it needs 0.6/1 kV and 4 × 95 written next to it to be complete. Change any block and you have a different cable: YJLV22 is the same thing with an aluminium conductor, YJV23 has a polyethylene outer sheath, YJV32 has steel wire armour.

Block 1: insulation and conductor material

The insulation letter is the one that sets the thermal rating, and there are only a handful in common use. YJ means XLPE and gives a 90 °C continuous conductor temperature. V means PVC and gives 70 °C. Y means PE, which is chosen for its electrical properties in communication and medium voltage designs rather than for its temperature performance. That single first block tells you the two things that determine the ampacity: the insulation material, and the temperature it is allowed to reach.

The conductor letter follows immediately. Copper is the default and is normally omitted entirely: YJV is a copper cable. L after the insulation means aluminium, so YJLV is XLPE insulated with an aluminium conductor. Aluminium conductors are legitimate and widely used for large distribution feeders, but they have a higher resistivity, so an aluminium cable needs roughly two sizes more than a copper cable for the same current, and it needs termination compound and compatible lugs. Get this right in the RFQ, because YJV and YJLV differ only by one letter and by a great deal of money.

Block 2: the armour and sheath digits

The digits at the end of the code are read in pairs, and the second digit is the outer sheath material, not a second armour. The first digit is the armour: 2 is a double layer of galvanised steel tape, 3 is a layer of fine galvanised steel wire, 4 is a layer of thick steel wire, and 6 is a non-magnetic metallic armour used where the cable is single-core. The second digit is the outer sheath: 2 is PVC and 3 is polyethylene.

So YJV22 is steel tape armoured with a PVC sheath, and YJV23 is the same armour with a polyethylene sheath, which is the usual choice for aggressive or chemically contaminated soil and for direct burial where the sheath is exposed to moisture for decades. YJV32 is steel wire armoured with a PVC sheath and is the cable for vertical shafts and tensile loads. YJV62 is non-magnetic wire armoured with a PVC sheath, and it exists because magnetic armour around a single conductor heats up under alternating current. If there is no armour, there are no digits: YJV is unarmoured with a PVC sheath, YJY is unarmoured with a polyethylene sheath.

Block 3: the fire performance prefixes

These are written in front of the type code, and they are the part buyers most often get wrong, because several of them sound alike and mean quite different things. ZR is the general flame-retardant prefix. Where a class is specified it appears as ZA, ZB, ZC or ZD, the four flame-retardant classes of GB/T 19666, with ZA the most demanding and ZD the least; ZC is the common commercial grade.

WD means low smoke and halogen free, so WDZ is a low smoke zero halogen flame-retardant cable and WDZN adds fire resistance. NH alone means fire resistant without the low smoke requirement. Usefully, the prefixes tell you two separate things, and they are not the same thing at all: a flame-retardant cable resists the spread of fire along its own length, while a fire-resistant cable keeps working while it is burning. A cable that passes one test can fail the other, and life-safety circuits are where the distinction is tested.

• ZR: flame retardant, general
• ZA, ZB, ZC, ZD: flame-retardant classes A to D of GB/T 19666, most to least demanding
• WD: low smoke, zero halogen; WDZ adds flame retardance
• WDZN: low smoke, zero halogen, flame retardant and fire resistant
• NH: fire resistant, for circuits that must survive a fire while operating
• Flame retardant and fire resistant are two different tests on two different properties

Control cables: KVV, KVVP and their variants

The K prefix marks the family of control cables, which are built for 450/750 V and for many cores rather than for large cross-sections. The remaining letters follow the same rules as power cable: KVV is PVC insulated and PVC sheathed, KVV22 is the armoured version, and KVVR has flexible conductors for wiring between a machine and its control cabinet.

The screen letters matter here more than anywhere else, because control signals are small. KVVP has a copper wire braid screen over the laid-up cores, KVVP2 uses a copper tape screen instead, and KVVP22 combines a braid screen with steel tape armour for a route that needs both electrical screening and mechanical protection. A braid is flexible and makes a good low-frequency return path; a tape gives higher coverage at high frequency but is mechanically weaker and carries less fault current. Where the control cable runs alongside a variable speed drive output, the screened and armoured variants are worth the extra cost.

Instrument and data cables: DJYPVP and the P letters

DJ marks the computer and instrument cable family, and the P letters inside it confuse everyone on first sight because their position changes their meaning. Read them in order: DJ is the family, the next letter is the insulation, then a P means the individual pairs are screened, then a letter for the sheath, then a final P for an overall screen. So DJYVP is polyethylene insulated with a PVC sheath and an overall braid screen, while DJYPVP is polyethylene insulated, individually screened pairs, PVC sheathed, with an additional overall braid screen.

The reason for two levels of screen is crosstalk. Individual pair screens stop one pair coupling into the next, and the overall screen stops external fields reaching the bundle. An analyser room or a plant with long 4-20 mA loops needs both. The tape equivalents follow the same pattern: DJYP2VP2 uses copper tape for both levels, and DJYP3VP3 uses an aluminium and plastic composite tape, which is cheaper and lighter but has a higher transfer impedance.

• DJYVP: PE insulation, PVC sheath, overall braid screen
• DJYPVP: individually screened pairs plus an overall braid screen
• DJYP2VP2: as DJYPVP with copper tape screens
• DJYP3VP3: as DJYPVP with aluminium and plastic composite tape screens
• DJYPVP22: pair and overall screens plus steel tape armour
• The final P is the overall screen; the P before the sheath letter screens the individual pairs

Reading the marking printed on the sheath

The printed marking on the sheath is the delivery note that cannot be lost. It carries the manufacturer, the full type code, the voltage rating, the number of cores and the cross-section, the standard, and the year of manufacture, and in most construction it also carries a sequential metre mark every metre along the length.

That metre mark is worth more than its size suggests. It is the only practical way to verify the length actually delivered on a drum, since a cable can otherwise only be measured by unwinding it or by weighing it. It is also the traceability link back to the production record, so if a drum is later found to be out of specification, the marking and the drum tag together identify exactly which production length it came from. Voltcore prints the brand, type, voltage, construction, standard and year with sequential metre marking, and supplies private label printing where the project requires it.

European and North American cross-references

Projects built to IEC or NEC rules use different naming, and a buyer who receives a Chinese code and needs to match it to a local specification is doing a translation, not a comparison. There is no exact one-to-one mapping, because the families are defined in their own standards, but the equivalents below cover most enquiries. The electrical and mechanical properties are what must match; the name is only a label.

One caution on the North American side: listing is a property of a specific product under a specific file number, not of a type code. Where a project requires a listed construction, ask for the listing evidence for that product and check it against the register rather than accepting the type name alone.