How to Read Cable Markings and Technical Data Sheets

What does a cable marking tell you?

Cable markings and data sheets provide traceability, but abbreviations vary by country and manufacturer. A designation may state the number of cores and the nominal cross-section, written as cores x cross-section in mm². Protective conductors, reduced neutrals and individually screened pairs need a clearer schedule, because a short code does not show them reliably.

Two cables with similar model names can differ in conductor class, insulation thickness or armour. Buyers should therefore compare the complete construction rather than relying on one familiar model code.

Engineering note: model abbreviations alone are not sufficient to judge technical equivalence. For background on how standards and test reports support a rating, see cable standards and test reports.

How do you read the voltage rating?

The voltage is usually the first figure to check. In a designation such as 0.6/1 kV, the first value is the nominal voltage between conductor and earth (U0), and the second is the voltage between conductors (U), following the IEC 60502-1 convention. Confirm that the pair suits the system voltage the cable will serve.

European flexible cables use the same logic. H07RN-F is rated 450/750 V under EN 50525-2-21, with EPR insulation, a polychloroprene sheath and a class 5 conductor. Solar DC cable is rated differently: cable such as H1Z2Z2-K, built to IEC 62930 and EN 50618, is rated 1.5 kV DC. Many datasheets also list a maximum permissible DC system voltage of 1.8 kV, so check which figure your design uses.

For medium voltage, IEC 60502-2 covers extruded-insulation cables from 6 kV (Um 7.2 kV) to 30 kV (Um 36 kV). IEC 60840 covers the range above 30 kV up to 150 kV (Um 170 kV). If a marking refers to a medium-voltage standard, confirm that the edition and voltage range match the project.

How do you check each element of a marking?

Each element of a marking should map to a line on the datasheet. The table below shows the usual formats and what to verify for each one.

Example formats are generic. Take the exact values for any size and construction from the manufacturer's datasheet and the cited standard edition.

What should the datasheet show beyond the marking?

A marking is a summary, so the datasheet should carry the detail. Look for these items:

• Conductor class, nominal insulation thickness and nominal sheath thickness.
• Approximate outer diameter and mass, which affect gland selection and shipping weight.
• Bending radius and tensile limit. The minimum bending radius depends on the cable type and construction, so take it from the manufacturer's datasheet rather than from a general rule.
• Temperature range for installation and for operation.
• Maximum conductor resistance, voltage rating and insulation properties.
• For signal cable, capacitance, impedance or attenuation where applicable.

Conductor resistance is a useful check. IEC 60228 sets maximum DC resistance at 20 °C for plain copper class 1 and class 2 conductors. For example, a 16 mm² copper conductor is limited to 1.15 Ω/km, and a 2.5 mm² conductor to 7.41 Ω/km. Tinned or other metal-coated conductors have slightly higher limits, so a datasheet for a tinned conductor should be checked against the tinned-conductor figure, not the plain copper one. The conductor classes and stranding article explains the class terms in more detail.

Why do drum labels and batch codes matter?

Markings may include the manufacturer, model, voltage, standard, production code and metre count. A drum label should connect the delivered length to the test and inspection records for that batch. Without this link, a cable on site is hard to trace back to the evidence behind its rating.

A practical test is a nameplate-style review. Before approving the print design, ask whether a technician receiving one drum could identify its voltage, construction, size, standard, manufacturer and batch without opening project emails. If the answer is no, improve the printing and the label schedule. Then:

1. Approve a marking sample before production.
2. Link each batch code to its test records.
3. Avoid ambiguous local abbreviations on export orders, and write out the full designation.

Frequently asked questions