HD 603 S1 vs HD 620 S2: Which European Document Your Cable Answers To

01What a harmonization document is — and is not

A CENELEC harmonization document — an HD — is not a European Standard (EN), and it is certainly not a national standard. It is an agreement between the national electrotechnical committees to align their own cable standards to one text, so that a cable built and tested to the document is acceptable across the harmonized market without each country re-testing it. Each country then publishes the result as its national standard, and that national number is what appears on the data sheet and in the quotation.

That is the single fact that explains most of the confusion in a European cable enquiry. A German specification says DIN VDE 0276-603; a Dutch one says NEN 3610-area practice; the cable maker's data sheet says HD 603 S1 and IEC 60502 in the same breath. All three are describing the same construction. The document does not replace the national standard, and the national standard does not replace the document — it is the document, under a national prefix.

Two structural rules follow from that, and they apply to both documents on this page. First, the document is split into parts: Part 1 is general requirements, and the numbered particular parts carry the individual cable types. Second, within those particular parts the type is defined by construction, not by application — which is why the same part contains unarmoured and armoured, concentric-neutral and plain variants under sub-letters.

02HD 603 S1: the 0,6/1 kV distribution family

Read the scope sentence before anything else, because it does two jobs at once — it fixes the voltage and it fixes where the cable belongs:

“HD 603 applies to cables of rated voltage U_o/U = 0,6/1 kV used in underground power distribution systems mainly for public distribution, of nominal voltage not exceeding 0,6/1 kV a.c. This part (Part 1) specifies the general requirements applicable to these cables, unless otherwise specified in the particular sections of this HD. Test methods are specified in HD 605 and in EN 60228, EN 60332-1-2 and EN 60811. The particular types of cables are specified in Parts 3 to 8.”

Four things are settled in that paragraph. The voltage is 0,6/1 kV, not "1 kV". The intended field is public underground distribution. Part 1 is general — it yields to a particular part wherever the two disagree. And the test methods are not invented in the document: they are borrowed from HD 605, EN 60228, EN 60332-1-2 and the EN 60811 series. The reference list in Part 1 adds three more that matter commercially: EN 50334 for marking by inscription, HD 308 for core identification, and IEC 60287 for current-rating calculation.

That last one is worth pausing on. The document does not print a current-rating table. It points at the calculation method instead. So when a European data sheet quotes an ampacity, that number comes either from the manufacturer's own calculation to IEC 60287 or from a national guide — it is not a table value you can point at inside HD 603 S1.

The particular types then split six ways, by insulation and by armour:

Part titles and the sub-type letters are as listed in the standard's own table of contents. The "what it produces" column is our summary of those titles, not a clause of the document. The document's full text is behind a paywall; only Part 1 up to the test definitions is publicly sampled.

The sub-lettering is finer than most specifications need, and that is deliberate. Part 5 alone runs from 5A to 5W because it has to cover concentric-neutral, CNE, service-cable and energy-board variants of the same XLPE construction. When a European specification says "HD 603 S1 Part 5" without a letter, it has named a family and not a cable.

03How a compound gets its name, and the three test classes

Part 1 also contains the sentence that trips up more non-European buyers than any other. It is about how the insulating and sheathing compounds are designated:

“The category in which a compound is placed according to its properties is determined by specific tests. The type designation is not directly related to the composition of the compound.”

A compound designation in this system — DIV4, DMV5, DIX8, DMV6 — is a statement about measured performance, not about a recipe. Two suppliers can reach the same DIX8 with different polymer systems. That matters to a buyer in two ways: a substitution claim that hinges on "same compound" is meaningless unless the declaration names the compound type; and a data sheet that lists the chemical family but not the type designation has not actually declared the compound at all.

The document's Table 2.1.1 organises the compounds into two families each for insulation and sheath:

• Insulation, thermoplastic: PVC or copolymers, and polyolefin (PO).
• Insulation, cross-linked: XLPE, EPR, and hard EPR (HEPR).
• Sheath, elastomeric: polychloroprene (PCP) and chlorosulfonated polyethylene (CSP) or similar polymer.
• Sheath, thermoplastic: PVC, polyethylene (PE), and polyolefin (PO).

The second half of Part 1's vocabulary is the test scheme, and it is the part that decides what a certificate actually proves. Four classes are defined, and they are not interchangeable:

Definitions summarised from the scope and definitions section of Part 1; the document notes that sample and routine tests may additionally be required by a type-approval scheme. When a quotation claims "tested to HD 603 S1", the useful question is which of the four classes the certificate covers, and for which cable length.

04HD 620 S2: the medium-voltage family, and Part 10-C

Above about 1 kV the harmonized system changes document. HD 620 S2 covers extruded-insulation distribution cables from 3,6/6 (7,2) kV up to and including 20,8/36 (42) kV, used in distribution networks where the system voltage does not exceed the maximum r.m.s. value U_m. As with HD 603 S1, Part 1 carries the general requirements; the particular constructions are in the lettered and numbered parts.

The part that carries most European MV orders is Part 10-C, and its scope is unusually specific — it names both the voltage and the construction in one sentence:

• Single-core power cables with XLPE insulation and PE or PVC sheath, for rated voltage U_o/U of 6/10 kV, 12/20 kV and 18/30 kV.
• Three-core power cables with XLPE insulation and PE or PVC sheath, for rated voltage U_o/U of 6/10 kV.
• Both for fixed installations.

Part 10-C also has a history worth knowing, because older quotations still carry the old part numbers. In the previous German implementation the single-core requirement sat in part 5-C and the three-core one in 6-C; the 2010 edition of HD 620 S2 merged the two into a single Part 10-C that contains the requirements and tests for all types. A quotation that cites "HD 620 5-C" is not wrong about the cable — it is citing a part number that no longer exists in the current document.

05Decoding N2XSY and its neighbours

European MV cable type codes are a compact build description, not a trade name. The order is fixed: the leading letters say what the cable is and to which document it belongs, then insulation, then screening and sheath. Read against a single-core screened MV construction, the code fills in like this:

• N — a standard cable to the German norms, and in an MV code specifically to HD 620 Part 10-C. An A in the position after it marks an aluminium conductor; its absence marks copper.
• 2X — cross-linked polyethylene (XLPE) insulation. The single Y is PVC; 2X is XLPE; the digit distinguishes the two.
• S — the metallic screen, a copper screen in this family. This is the layer that makes an MV cable an MV cable; it is not armour.
• Y — PVC outer sheath. A second 2Y, or a 2Y variant, marks a PE sheath instead.

So N2XSY reads as: a standard MV cable to HD 620 Part 10-C, XLPE insulation, copper screen, PVC sheath. Push one letter and the cable changes family: N2XS2Y is the same construction with a PE sheath instead of PVC, and NA2XSY is the aluminium-conductor version.

What the document fixes for that construction, and what it leaves to the maker, is the distinction that matters when two quotations are compared side by side. Below are the values two independent manufacturers publish for the same N2XSY range — they agree item by item, which is what makes them usable as a reference rather than as a single vendor's claim.

Values as published for the same single-core screened MV range by two independent European manufacturers, which agree item by item. They describe a manufacturer's catalogued range, not a table inside HD 620 S2 — the document's own tables are not public. The reaction-to-fire class in particular is a declaration for a specific product, and it changes with sheath material.

06NYY vs N2XY: the LV split most orders actually name

At 0,6/1 kV the two codes that appear on more European enquiries than any others are NYY and N2XY. They describe the same physical arrangement — copper conductor, insulated cores, filler, PVC outer sheath, no armour — and differ in one layer, exactly as the letters say. NYY carries PVC insulation on each core and a PVC sheath; N2XY carries XLPE insulation and the same PVC sheath. The 2X is the whole difference, and it moves the continuous conductor temperature by twenty degrees.

That twenty degrees is the commercial decision. PVC insulation is rated for a continuous conductor temperature of 70 °C with a short-circuit allowance of about 160 °C; XLPE is rated 90 °C continuous and 250 °C short circuit. For the same cross-section the XLPE cable therefore carries more current, and the gap widens further where ambient temperature is high or where several cables share a tray. On a cost-per-metre comparison the PVC cable usually wins; on a cost-per-amp or a cost-over-life comparison the answer often reverses.

Compiled from four independent references that agree type by type. Two points to keep straight: the J/O suffix decides the protective-earth arrangement and has nothing to do with the insulation; and the leading N in NYY means Normenleitung, a cable to the German norms — the bracketed (N)YY or plain YY form is used where the cable is cited against the European harmonized document instead. Neither NYY nor N2XY is armoured, so neither is a direct substitute for a steel-wire-armoured cable on a route that needs mechanical protection.

07What a harmonization document does not settle

It does not give you a CPR class

The cable's reaction to fire — the A to F class with its smoke, droplet and acidity sub-classes — is declared for the finished product under the construction-products regime, and classified under EN 13501-6. It is not a property of the document. The same N2XSY range can be quoted Eca by one maker and something else by another depending on the sheath compound and the tested configuration. Ask for the declaration of performance, not for the standard number.

It does not print your ampacity

HD 603 S1 points to IEC 60287 for current-rating calculation rather than carrying a rating table; the ambient temperature, the grouping, the installation method and the soil conditions all feed the answer. An ampacity quoted without those four conditions stated is not comparable with any other quotation, even when both cite the same document.

It is not a substitute for the national adoption

Where a project's specification, the authority having jurisdiction or the utility's own standard names a national number, the cable has to be evidenced against that number. The harmonized text sits underneath it and is normally the same requirements, but the document that applies is the one the project wrote down. Confirm which number the approval is actually against before the drum is made.

08Mapping to IEC and to GB/T

The same physical cable is described by three further systems, and the mapping is at the level of construction rather than of standard number. The IEC counterpart of the LV family is the IEC 60502-1 construction at 0,6/1 kV, and of the MV family the IEC 60502-2 construction at 6/10 kV and above — which is why European data sheets routinely print the IEC number next to the harmonized one. The Chinese counterpart is the GB/T 12706 series, whose first part covers the 1 kV class and whose later parts cover the 6 kV to 35 kV classes.

The IEC and Chinese columns are given as the corresponding document layer for the same construction; they are not adoption relationships with the harmonized documents. The Chinese type-code column follows the designation published on our own product pages. No clause or table value from the harmonized documents is quoted here.

09What this page publishes, and what it will not

The scope sentences, the part structure, the compound families and the four test classes come from the publicly sampled Part 1 of HD 603 S1 and from published catalogue records of both documents, all listed in Sources. The MV construction values in Table 3 are manufacturer data-sheet figures for the same range from two independent makers, presented as such. Where a document is not available, the page stops at the name: the full texts of HD 603 S1 Parts 3 to 8 and of HD 620 S2 Part 10-C are not public, so no clause number and no table value from either is quoted. The voltage split, the part mapping and the inside-the-code letter order are given because they are cross-checked between the document records and independent references.

What the page does not do is approve an installation. It will not tell you that a given cable satisfies your project — that depends on the exact construction, the declaration of performance, the national adoption named by the specification, and the authority having jurisdiction. Bring us the specification and the route, and we will work the comparison against a construction we actually build.