Solar Cable Cross-Reference: EN 50618 vs IEC 62930 and NB/T 42073

01What a solar cable is, before the code letters start

The DC side of a photovoltaic system runs from the module strings, through the combiner box, to the inverter. The cable on that side carries a DC voltage that a normal building wire is not built for, sits outdoors in UV and ozone for a design life measured in decades, and is expected to be replaced far less often than the modules around it. That combination is what the four standards below are written around.

All four land on the same physical recipe for the common product:

• Conductor: tinned annealed copper, so the strand surface resists the corrosion that bare copper develops outdoors; flexible Class 5 stranding where the cable has to follow module frames and trays.
• Insulation and sheath: a cross-linked, halogen-free compound, so the cable survives heat, UV and fire without releasing corrosive halides.
• Voltage: a rated DC voltage of 1.5 kV between conductors and between conductor and earth — the level the standard 1500 V DC string architecture is built to.
• Temperature: a normal continuous conductor temperature of 90 °C, with a defined allowance for excursions to 120 °C.

Where they diverge is the part a buyer actually trips over: the two-character or six-character code stamped on the sheath, the standard named on the certificate, and the optional tests — salt spray, bundled flame, high-temperature pressure — that one document requires and another does not. The rest of this page works through those one system at a time.

02IEC 62930: the international reference

IEC 62930:2017 is published by IEC TC 20 (Electric cables), Edition 1.0, dated 2017-12-13, and carries the ICS codes 29.060.20 and 27.160. Its title states the key limitation directly: Electric cables for photovoltaic systems with a voltage rating of 1,5 kV DC.

The scope, as published, applies to single-core cross-linked insulated power cables with a cross-linked sheath, for use at the direct current side of photovoltaic systems, with a rated DC voltage up to and including 1.5 kV between conductors and between conductor and earth. Two details in the scope matter for procurement: the standard covers both halogen-free low-smoke cables and cables that can contain halogens, so an IEC 62930 claim on its own does not prove a halogen-free construction; and the cables are stated to be suitable for use with Class II equipment as defined in IEC 61140, which is what lets a properly built array run without earthing the DC side.

On temperature, the scope sets a normal continuous maximum conductor temperature of 90 °C, and a permissible period at a maximum conductor temperature of 120 °C limited to 20 000 hours. A note adds that the expected period of use under the specified normal conditions is at least 25 years.

What the standard text adds on construction

The published preview of the standard — the first chapters, which are what is available to check against — sets the conductor rule plainly: the conductor must be copper to IEC 60228, and each wire must be tinned with a continuous coating free of visible gaps. Where the cable is directly connected to a module, the conductor is Class 5 flexible; where it is a fixed installation that does not directly connect to a module, Class 2 is permitted. Insulation must be a cross-linked compound, extruded in one or more non-separable layers — and the standard notes that multiple layers do not amount to "double insulation" in the IEC 61140 sense. The routine-test definition is also worth carrying into a supplier question: a routine test is performed on every finished length, not on a sample.

03EN 50618 and the H1Z2Z2-K code, decoded

EN 50618:2014 is the European standard, published by CENELEC and taken into national systems as BS EN 50618, IS EN 50618, NEK EN 50618 and SFS-EN 50618; the BSI record dates the British edition 2015-02-28. Its scope is the same product as IEC 62930 and states it the same way: low smoke halogen-free, flexible, single-core power cables with cross-linked insulation and sheath, for the DC side of photovoltaic systems, nominal DC voltage 1.5 kV between conductors and between conductor and earth, suitable for Class II equipment, normal maximum conductor temperature 90 °C with 20 000 h permitted at 120 °C, and a note that the expected period of use is at least 25 years.

The difference a buyer sees is the designation. Under EN 50618 the cable carries the harmonised code H1Z2Z2-K — the string stamped on the sheath next to the standard number. Unlike the spelled-out Chinese or North American codes, this one is a compact position-based code, and the positions are what need decoding.

Where the decoding is not settled

Manufacturer literature reads the middle of the code two ways, and the honest move is to show both rather than pick one. In one reading the 1 is a rated-voltage field: the code sets the 1.0/1.0 kV AC class, and each Z2 marks a cross-linked halogen-free compound, one for insulation and one for sheath. In another reading the 1 denotes the highest mechanical requirement and Z2 denotes ozone resistance, applied once to insulation and once to sheath. A third variant reads Z2 as a flame-retardancy class. All three agree on the ends: H is a harmonised European type and K is a Class 5 flexible conductor. The rule to carry away is that the position order is a convention, the field meaning is not self-evident from the letter, and the authority is the EN 50618 standard sheet — not the code string and not a supplier's FAQ page.

PV1-F: the older TÜV code that predates the harmonised one

Before EN 50618, the European-market PV cable was certified to TÜV 2PfG 1169 and designated PV1-F. That code is not position-based in the same way; it is a type name. Its published ratings differ from the EN 50618 cable in a way that matters at the string level: PV1-F is rated 0.6/1.0 kV AC with a maximum permissible DC operating voltage of 0.9/1.8 kV, against the EN 50618 cable's 1.0/1.0 kV AC and 1.5/1.5 kV DC. Both are used on 1500 V DC strings, but the certified DC basis is set by the standard under which each is tested, and a specification that names the wrong one can be quoting a different class than it intends.

Where the two are built to the same construction — tinned Class 5 copper, electron-beam cross-linked XLPO insulation bonded to an XLPO sheath, halogen-free — a single production line can satisfy both, and suppliers often list EN 50618, IEC 62930 and TÜV 2PfG 1169 on the same datasheet. That is a statement about the construction, not about three separate certificates; the certificate scope is still the thing to read.

04China: NB/T 42073 and the PV-YJYJ code

China's domestic standard for this cable is NB/T 42073-2016, Cables for photovoltaic power generation systems. It was issued by the National Energy Administration on 2016-08-16, took effect on 2016-12-01, and is under the electrical-wire-and-cable standardisation committee, with the Shanghai Cable Research Institute among the drafting bodies. It is an industry standard (NB/T), not a GB — which is the first thing to know when a Chinese specification names it.

Its scope covers the DC side of a photovoltaic system: the series cable between modules, the parallel cable between strings and from string to the DC combiner box, and the cable from combiner box to inverter, and it also extends to the AC cable between inverter and grid. The ratings are stated as 1.5 kV DC (maximum 1.8 kV) and 0.6/1 kV AC, with a tinned annealed copper conductor and halogen-free low-smoke thermoset insulation and sheath, a long-term conductor working temperature of 90 °C and an expected life of 25 years.

PV-YJYJ and how the Chinese code is written

The Chinese designation is a product-code string rather than a compact position code, and its parts are spelled out in the standard's designation clause and in supplier literature. The core form is PV-YJYJ, optionally prefixed with a flame-retardant attribute and suffixed with an additional attribute. The worked example in the designation clause is telling: a 1.5 kV DC single-core 4 mm² PV cable is written PV-YJYJ DC 1.5kV 1×4mm² NB/T 42073-2016, and an AC 3-core 6 mm² cable with salt-spray and bundled-flame-C requirements is written PV-ZC-YJYJ (Y) AC 0.6/1kV 3×6mm².

Decoded from the designation clause reproduced in supplier and training material for NB/T 42073-2016; the library holds no copy of the standard text, so no clause number is quoted. Field positions follow the published example.

What NB/T 42073 adds over IEC 62930

On the substance the two are close — the scope, the voltage, the conductor, the halogen-free thermoset build and the 90 °C working temperature all line up. The difference is in the tests, and it runs one way: Chinese material describing the comparison states that NB/T 42073 adds a high-temperature pressure test on the insulation and sheath, a bundled-flame test, and a salt-spray test on top of the IEC 62930 programme, and that these additions suit the inland-desert and coastal-salt conditions found on Chinese projects. Where several sources describe the two as "broadly the same, with slight differences in individual requirements and test methods", that is the level of resolution available without the full standard texts — enough to map the pair, not enough to quote a table value from one against the other.

Sources: IEC 62930:2017 and EN 50618:2014 scope text; NB/T 42073-2016 scope as published in industry and supplier material; UL 4703 Scope 1.1 as published by UL Standards & Engagement. No table values are quoted where the standard text was not available.

05North America: UL 4703 and PV Wire

North America does not use a harmonised position code for this product. The standard is UL 4703, Photovoltaic Wire, and the type name on the cable is PV Wire. The published scope is worth reading in full, because it puts the whole North American position in one sentence: UL 4703 covers single-conductor, insulated and integrally or non-integrally jacketed, sunlight-resistant photovoltaic wire rated 90, 105, 125 or 150 °C dry and 90 °C wet, at 600, 1000 or 2000 V, for the interconnection wiring of grounded and ungrounded photovoltaic power systems as described in Article 690, Part IV (Wiring Methods) and other applicable parts of the National Electrical Code.

Three points follow from that wording. First, the North American system is organised around Article 690 of the NEC rather than around a product code, so the compliance question is "is this listed PV Wire used per Article 690" rather than "does this match H1Z2Z2-K". Second, the voltage set is 600, 1000 or 2000 V — not the 1.5 kV of the IEC/EN world — so a 1500 V DC string on a North American project is a different class of question than the same string in Europe. Third, "sunlight resistant" is written into the scope, not treated as an extra: a PV Wire without it is not PV Wire.

06The cross-reference table

The table below maps the designations for the common 1.5 kV DC single-core solar cable across the four systems. Read it as a mapping of product to product, not as a statement that any one certificate satisfies another jurisdiction.

Cells marked "—" mean the system does not use that field, not that the requirement is absent. Where a cell defers to "the standard" or "the listing", the value lives in text the library does not hold, so it is not guessed here.

07What does not translate

Four misreadings cause most of the trouble when a PV specification crosses a system boundary.

1. The same letters can carry different ratings

PV1-F and H1Z2Z2-K are both European solar-cable codes, but they are certified under different standards and carry different DC ratings — PV1-F at 0.9/1.8 kV maximum permissible DC operating voltage under TÜV 2PfG 1169, H1Z2Z2-K at 1.5/1.5 kV DC under EN 50618. A specification that swaps one for the other without checking the rating has changed the class it is buying.

2. A national difference is not a separate standard

NB/T 42073 read on its own is a Chinese industry standard. Read through the IECEE difference table it is China's national difference against IEC 62930. Both statements are true, and which one a buyer needs depends on whether the project is certified to the IEC standard with national deviations or to the national standard directly.

3. The North American voltage set does not line up

UL 4703 is written around 600, 1000 and 2000 V. The IEC/EN world is written around 1.5 kV. A datasheet that lists "1500 V" against a UL 4703 claim is describing the system it is intended for, not a rating the standard defines — the standard defines the three values above, and the listing states which one applies.

4. Certification attaches to the construction, not the family

A certificate for one construction — one conductor class, one compound, one cross-section range — does not extend to another. Changing the conductor from Class 5 to Class 2, or the compound from halogen-free to a halogen-containing variant, moves the product outside the scope that was tested. This is why the sheath print and the certificate scope are read together, and why a type code alone settles nothing.

08What this page publishes, and what it will not

The tables above are built from standard records, published scope text and manufacturer datasheets, and every voltage and temperature in them is taken from a document listed in Sources rather than inferred from a code. Where a document was not available, the page says so and stops at the standard name: the EN 50618 and IEC 62930 layer-by-layer test comparison is not published here because the full texts were not obtained, the NB/T 42073 designation is decoded without a clause number because the standard text was not held, and the UL 4703 row states the three published voltages rather than translating them into an IEC class.

What this page does not do is decide a project. It will not tell you that a particular H1Z2Z2-K cable satisfies a particular NB/T 42073 or UL 4703 requirement on your job, because that depends on the build, the certificate scope and the accepting authority. Bring us the two specifications and the site conditions, and we will work the comparison against a construction we actually build.