A solar cable data sheet may show both AC U0/U 1.0/1.0 kV and DC U0/U 1.5/1.5 kV. The short answer is that these are separate voltage ratings for the same cable under AC and DC conditions.
For a photovoltaic DC circuit, the 1.5/1.5 kV DC or 1500 V DC value is the relevant rated-voltage statement. The 1.0/1.0 kV AC value is the cable’s AC rating. The two values are not added together, and 1500 V DC is not a conversion that an installer should calculate from 1 kV AC.
This marking is common on H1Z2Z2-K photovoltaic cable. However, the voltage line alone does not prove compliance with EN 50618, IEC 62930 or a project specification. Buyers should match the complete cable legend to the data sheet, certificate, approved factory and size range.
For a broader explanation of PV cable construction and standards, see our solar cable guide.
Quick interpretation of the voltage markings
| Marking on a cable or data sheet | What it means | What it does not mean |
|---|---|---|
AC U0/U 1.0/1.0 kV | Rated AC voltage is 1.0 kV from conductor to earth and 1.0 kV between conductors | The two values do not add up to 2 kV |
DC U0/U 1.5/1.5 kV | Rated DC voltage is 1.5 kV from conductor to earth and 1.5 kV between conductors | It does not mean 1.5 kV on each pole can be combined into a 3 kV circuit |
1500 V DC | A single-value presentation of the cable’s 1.5 kV DC rating, subject to the stated standard and product documents | It does not define the permitted voltage of every connector, module, fuse or inverter in the circuit |
Maximum permissible DC voltage 1.8 kV | A maximum cable operating value stated under defined product or standard conditions | It is not a new 1.8 kV nominal system rating |
6.5 kV AC or 15 kV DC test voltage | A factory or type-test voltage applied for the specified test method and duration | It is not a continuous service voltage |
The exact wording varies. One approved product may print 1.5/1.5 kV DC, while another may print 1500 V DC or include a maximum value in parentheses. Use the format on the applicable certificate and approved print legend rather than copying a marking from another supplier.
What U0/U means on a solar cable
Cable voltage ratings often use the notation U0/U:
U0is the rated voltage between a conductor and earth.Uis the rated voltage between conductors.
The distinction is easy to see on a conventional 0.6/1 kV power cable. It is rated 0.6 kV between conductor and earth and 1 kV between conductors.
On a typical H1Z2Z2-K solar cable, the values are equal:
- AC:
U0/U = 1.0/1.0 kV - DC:
U0/U = 1.5/1.5 kV
That is why the marking repeats the same number. The slash separates two reference voltages; it is not a mathematical operator.
IEC 62930 covers single-core, cross-linked insulated and sheathed PV cables intended for the DC side of photovoltaic systems, with a rated DC voltage up to 1.5 kV between conductors and between conductor and earth. EN 50618 covers the H1Z2Z2-K low-smoke, halogen-free construction used for the same part of a PV system.
Why one cable can have both an AC and a DC rating
An insulation system can be evaluated and assigned separate AC and DC voltage ratings. AC and DC place different electrical stresses on insulation, accessories and complete circuits, so the values must come from the product standard and verified data. They should not be created with a conversion formula.
It may be tempting to multiply 1.0 kV AC by the square root of two and round the result to 1.5 kV DC. That arithmetic compares the peak of a sine wave with its RMS value, but it does not establish a cable rating. Standard requirements also consider construction, insulation thickness, ageing, long-term DC stress and prescribed voltage tests. Read the declared AC and DC ratings as separate qualified values.
The presence of an AC value does not change the cable’s main application. H1Z2Z2-K and IEC 62930 PV cable are specified for the DC side of photovoltaic systems. Using the cable on an inverter’s AC output requires a separate check against local wiring rules, the intended AC cable standard, installation method, fire requirements and termination system.
Where 1500 V DC solar cable belongs in a PV system
The cable marking should be matched to the circuit section, not to the word “solar” alone.
| PV circuit section | Normal current type | Main cable-selection check |
|---|---|---|
| Module leads and module-to-module connections | DC | Approved PV cable, system voltage, connector compatibility and outdoor exposure |
| String-to-combiner connection | DC | PV cable rating, design current, route length, voltage drop and protection |
| Combiner-to-inverter input | DC | Maximum DC voltage, combined current, termination and installation method |
| Inverter output to AC distribution | AC | AC power cable selected under the applicable local and product standards |
| Battery connection | DC | Battery-system cable and equipment requirements, which are not automatically covered by a PV cable designation |
| Underground transition | DC or AC | Specific approval for conduit, burial, water exposure and mechanical protection |
A buyer comparing the two sides of an inverter can use our low-voltage power cable guide for the AC distribution side. A PV string cable should not be treated as the default AC output cable merely because its data sheet includes 1.0/1.0 kV AC.
1500 V DC cable does not make the entire system a 1500 V system
The finished DC circuit is limited by its lowest-rated applicable component. A 1500 V DC cable cannot raise the rating of a 1000 V connector or a 1100 V inverter input.
Check at least the following:
- PV module maximum system voltage
- Maximum cold-corrected string open-circuit voltage
- Cable rated voltage
- Connector and branch-connector voltage
- Combiner-box terminals and fuse holders
- DC fuses, isolators and circuit breakers
- Surge-protection devices
- Inverter maximum DC input voltage
- Junction boxes, glands and other terminations
- Local installation and access requirements
The string voltage calculation must account for the rise in module open-circuit voltage at low temperature. An illustrative estimate is:
Maximum string Voc ≈ number of modules in series × module Voc at STC × cold-temperature correction
For example, assume 28 modules, a module Voc of 49.5 V, a voltage temperature coefficient of -0.25%/°C, and a project minimum temperature of -10°C.
Cold correction = 1 + 0.0025 × (25 - (-10)) = 1.0875
Estimated maximum string Voc = 28 × 49.5 × 1.0875 = 1,507 V
The string is below 1500 V at standard test conditions but exceeds 1500 V in this simplified cold-weather check. The final calculation must follow the module manufacturer’s data, the applicable design standard and local rules. A cable data sheet that also mentions 1.8 kV maximum does not override a 1500 V module, connector or inverter limit.
What the 1.8 kV DC value means
Many H1Z2Z2-K data sheets state a nominal DC voltage of 1.5/1.5 kV and a maximum permissible DC operating voltage of 1.8 kV. Some express this as 1.5/1.5 (1.8) kV DC.
These numbers serve different purposes:
1.5/1.5 kV DCis the rated-voltage marking.1.8 kV DCis a stated maximum permissible value under the relevant cable conditions.
Do not specify an 1800 V PV array just because the cable document contains 1.8 kV. The nominal system voltage still has to fit the standards and every component in the circuit. The project engineer should also check overvoltage conditions, earthing arrangement and equipment documentation.
Test voltage is not operating voltage
A PV cable document may state a completed-cable test such as 6.5 kV AC for 5 minutes or an alternative 15 kV DC test. A higher test value checks insulation integrity for a controlled duration. It does not permit continuous operation at that voltage.
Keep these three lines separate when reviewing a data sheet:
| Data-sheet line | Purpose |
|---|---|
| Rated voltage | Defines the cable’s normal voltage class for the stated application |
| Maximum permissible operating voltage | Defines a higher cable limit under specified conditions |
| Test voltage and duration | Defines a test used to verify insulation integrity |
A quotation that advertises only the highest number can mislead buyers. Ask the supplier to identify which value is rated, which is maximum and which is used only during testing.
1500 V DC cable versus ordinary 0.6/1 kV AC power cable
The conductor does not become a different metal when current changes direction. The real selection boundary is the cable’s complete design, test scope and intended installation.
| Selection point | H1Z2Z2-K or IEC 62930 PV cable | Typical 0.6/1 kV AC power cable |
|---|---|---|
| Primary circuit | PV array DC side | AC power distribution |
| Common construction | Flexible single-core tinned copper with cross-linked insulation and sheath | Single-core or multicore copper or aluminium, with construction defined by its own product standard |
| Common voltage statement | 1.5/1.5 kV DC and, for H1Z2Z2-K products, 1.0/1.0 kV AC | 0.6/1 kV AC; any DC use must be supported by the product data and rules |
| Environmental focus | Long-term outdoor PV exposure, including specified UV, ozone and weather tests | Varies widely by product; an AC cable can be indoor or outdoor if its data supports the route |
| Connection system | PV connectors, module junction boxes, combiner boxes and inverter DC inputs | Lugs, terminals, glands, joints and AC switchgear selected for the cable construction |
| Substitution rule | Must satisfy the PV standard, voltage, route and connector system | Cannot replace exposed PV string cable based on conductor size and AC voltage alone |
The common claim that “DC cable is always single-core and AC cable is always multicore” is too broad. AC circuits can use single-core cables, and some PV assemblies use paired constructions. Product designation, approval and installation conditions decide suitability.
Does a 1500 V system reduce cable loss?
The printed 1500 V DC rating does not reduce loss by itself. A higher-voltage system can transmit the same power at lower current when the system architecture uses that higher voltage.
The basic relationships are:
Power = Voltage × Current
Conductor loss = Current² × Resistance
In a simplified comparison at the same power, increasing voltage from 1000 V to 1500 V reduces current to two-thirds of the previous value. With the same conductor resistance, resistive loss becomes about 44% of the former value. Real PV design is more involved because module string length, MPPT layout, parallel circuits, temperature, cable size and equipment limits all change the result.
This is why 1500 V architecture can reduce the number of parallel circuits and some balance-of-system equipment in large projects. It does not allow a designer to ignore ampacity, voltage drop or connector ratings.
How to read a complete H1Z2Z2-K cable legend
An illustrative surface marking could look like this:
KINGFORYOU H1Z2Z2-K 1 × 6 mm² AC 1.0/1.0 kV DC 1.5/1.5 kV EN 50618 IEC 62930 [APPROVAL MARK] 2026 LOT PV0814 METER 0125
This is an example, not a print template for every order. Each part should be checked:
| Printed item | Buyer verification |
|---|---|
KINGFORYOU | Brand or manufacturer identity matches the commercial and technical documents |
H1Z2Z2-K | Cable designation is covered by the quoted standard and certificate |
1 × 6 mm² | Single-core construction and nominal conductor size match the order |
AC 1.0/1.0 kV | AC rated-voltage statement matches the approved data sheet |
DC 1.5/1.5 kV | DC rated-voltage statement matches the standard and certificate |
EN 50618 and IEC 62930 | Both claims are supported separately when both are printed |
| Approval mark | Mark format, certificate holder, factory and product range are valid |
| Year, batch and metre mark | Delivered reels can be traced to production and test records |
Our cable jacket markings guide explains how to check manufacturer identification, voltage, standards, certification marks and batch traceability across other cable types.
What the voltage marking cannot tell you
1500 V DC answers one part of the specification. It does not confirm:
- Conductor material or maximum conductor resistance
- Conductor cross-section and corrected current capacity
- Voltage drop over the planned route
- Cable outer diameter and connector seal range
- Minimum bending radius
- Continuous conductor temperature
- Minimum installation or fixed-service temperature
- UV, ozone, water, chemical or abrasion performance
- Direct-burial or permanent-immersion suitability
- Flame, smoke or halogen performance
- Certification holder, factory scope or covered size range
Voltage rating and conductor size solve different problems. Use the solar cable size guide to compare 4 mm², 6 mm² and 10 mm² cable, including route length, voltage drop, temperature correction, grouping and connector limits.
Can a 1500 V DC cable replace a 1000 V PV cable?
A higher DC voltage rating can satisfy the voltage part of a lower-voltage circuit, but that does not make two product specifications interchangeable.
For example, an existing project may name PV1-F under a particular TÜV specification, while a new cable is H1Z2Z2-K under EN 50618. Before substituting, confirm:
- Whether the contract requires the exact cable designation
- Whether the authority or project engineer accepts the alternative standard
- Conductor size, resistance and strand construction
- Cable outer diameter and connector approval
- Insulation and sheath construction
- Temperature and environmental tests
- Fire-performance requirements
- Certificate holder, factory and approved size range
Our PV1-F vs H1Z2Z2-K comparison covers the specification differences in more detail. A 1000 V cable should not be used in a 1500 V DC circuit unless its exact approved documentation includes that 1500 V application.
Procurement checks for a 1.5 kV DC solar cable
Send enough information for the supplier to quote a defined product rather than a generic “1500 V solar wire.”
| RFQ field | Information to provide or request |
|---|---|
| Project market | Country, local rules and approving authority |
| Circuit | Module lead, string, combiner-to-inverter or another DC route |
| Cable designation | H1Z2Z2-K, 62930 IEC 131 or the exact project designation |
| Required standard | EN 50618, IEC 62930 or both |
| Voltage legend | Exact required AC and DC marking format |
| System voltage | Nominal DC voltage and calculated maximum cold-weather string voltage |
| Conductor | Tinned copper, conductor class, size and resistance requirement |
| Materials | Insulation and sheath construction, including halogen requirement |
| Route | Exposed, tray, conduit, buried, wet, floating or moving tracker section |
| Temperature | Ambient, installation and conductor-temperature requirements |
| Connector | Manufacturer, series, contact, accepted size and cable outer-diameter range |
| Documents | Data sheet, certificate, test report, declaration and batch record as required |
| Marking | Brand, type, size, voltage, standard, approval, lot and metre mark |
| Packaging | Length per coil or drum, reel type, label and export packing |
Before mass production, approve the surface-print proof and reel-label layout. When the order is ready, compare the physical marking with the certificate, data sheet, packing list and batch test record.
For a quotation based on a defined voltage marking and project standard, send the RFQ details through the KingForYou Cable contact page.
Frequently asked questions
Does 1.0/1.0 kV AC mean the cable is rated for 2 kV?
No. The first value is conductor to earth, and the second is conductor to conductor. They are not added together.
Are 1500 V DC and 1.5/1.5 kV DC the same marking?
They can describe the same 1.5 kV DC voltage class, but the presentation depends on the standard, certificate and product legend. Use the exact approved format for the offered cable.
Why are both U0 and U equal on this solar cable?
The PV cable is rated at the stated value both between conductors and between conductor and earth. The repeated values record those two conditions.
Can a system operate continuously at 1.8 kV DC if the cable lists 1.8 kV maximum?
Do not treat 1.8 kV as a new nominal system rating. The system must stay within the module, connector, protection-device, inverter and code limits as well as the cable conditions.
Does a 6.5 kV AC test voltage mean the cable can operate at 6.5 kV?
No. Test voltage is applied for a defined test duration to check insulation integrity. It is separate from rated service voltage.
Can H1Z2Z2-K be used on the inverter AC output?
The data sheet may include a 1.0/1.0 kV AC rating, but that line alone is not approval for every AC installation. Confirm the AC-side product standard, local wiring rules, installation route, fire requirements and terminations.
Is every H1Z2Z2-K cable also certified to IEC 62930?
No. H1Z2Z2-K is associated with EN 50618. If IEC 62930 is required, verify that the offered product documents and certification scope state it separately.
Does the 1500 V DC marking determine whether I need 4 mm² or 6 mm² cable?
No. Voltage rating and conductor size are separate checks. Size depends on current, corrected ampacity, cable length, voltage-drop target, installation method and connector compatibility.
Does a printed standard number prove certification?
No. It is a product claim. Verify the certificate or test documentation against the manufacturer, production factory, cable type, voltage, size range and current certificate status.
Final buyer check
Read 1.0/1.0 kV AC and 1.5/1.5 kV DC as two declared ratings for different electrical conditions. For the PV array DC side, 1500 V DC is the relevant rated-voltage line. It does not replace the system voltage calculation, equipment checks or certificate review.
A correct order should tie together five items: the project circuit, applicable standard, complete cable construction, approved voltage legend and matching technical documents. If any one of those items changes, review the cable selection again before production or installation.
