IEC 60502 Part 1 and Part 2: Which Voltage Range Does Each Cover

One standard, two voltage bands

IEC 60502 covers power cables with extruded insulation for rated voltages from 1 kV up to 30 kV, and it does so in two parts divided at the low-voltage/medium-voltage boundary:

• IEC 60502-1 — power cables with extruded insulation for rated voltages from 1 kV up to and including 3 kV
• IEC 60502-2 — power cables with extruded insulation for rated voltages from 6 kV up to 30 kV

The practical consequence is that a single voltage rating determines which part governs the construction, the insulation thickness and the test requirements. A 0.6/1 kV cable is a Part 1 cable; a 6/10 kV or 18/30 kV cable is a Part 2 cable.

How this appears on a real product range

The manufacturer's XLPE selection sheets list the applicable standards for the whole YJV family as IEC 60502 and IEC 60228, with IEC 60332-3 added for the flame-retardant ZR-YJV variant only, and GB/T 12706 with GB/T 18380.3 as the Chinese equivalents.

The voltage ratings offered across that family run from 0.6/1 kV through 3.6/6 kV, 6/10 kV, 8.7/15 kV, 12/20 kV and 18/30 kV — the range covered by IEC 60502-1 and IEC 60502-2. The 21/35 kV and 26/35 kV ratings in the same series sit above IEC 60502-2 and follow IEC 60840 (in China, GB/T 12706.3). That is a useful check when reviewing a quotation: a construction quoted to Part 1 for a 12/20 kV duty, or to Part 2 for a 0.6/1 kV duty, is a sign the schedule was copied rather than derived.

The standards that attach to it

IEC 60502 never stands alone in a specification. The conductor is separately covered by IEC 60228, which defines the classes of conductor — Class 1 solid, Class 2 stranded for fixed installation, and the finer-stranded Class 5 and Class 6 for flexible applications. The manufacturer's construction statements cite Class 2 to IEC 60228 for both the low- and medium-voltage ranges.

Where fire performance is specified, the flame-propagation tests come from the IEC 60332 series (with GB/T 18380.3 as the Chinese counterpart), halogen acid gas evolution from IEC 60754 and smoke density from IEC 61034. These are separate standards measuring separate properties — a cable meeting a flame test is not automatically low-smoke or halogen-free.

Other national standards

Projects frequently require a national standard rather than, or in addition to, the IEC one. The manufacturer's sheets note that BS, DIN and ICEA constructions are available on request.

This flexibility has a limit worth stating plainly: a cable built to one standard is not automatically compliant with another. Insulation thickness, voltage designation and test voltages differ between systems, so where a project requires a specific national standard it should be named at enquiry stage rather than assumed from an equivalent IEC type.