What the letters mean
The designation follows the European harmonised code. H means a harmonised type; 07 means 450/750 V; V means PVC insulation. The final letter describes the conductor: U for a solid conductor (Class 1 to IEC 60228), R for a rigid stranded conductor (Class 2) and K for a flexible conductor made of many fine wires for fixed installation (Class 5). The construction standard in Europe is EN 50525-2-31 (formerly HD 21.3); the IEC equivalents are 60227 IEC 01 for the solid and stranded versions and 60227 IEC 02 for the flexible version. In Thailand the same designs sit under TIS 11 Part 3, which has been mandatory since 30 July 2013.
So all three share the insulation compound, the voltage and, size for size, roughly the same insulation wall. A buyer comparing them is really comparing solid, stranded and flexible conductors, and the class system is explained in IEC 60228 conductor classes.
Side by side at 2.5 mm2
The reference values below come from public datasheets and a partner plant catalogue for 2.5 mm2. Outer diameters vary by maker and colour, so treat them as typical across the category and confirm against the datasheet for the order.
| Item | H07V-U | H07V-R | H07V-K |
|---|---|---|---|
| Conductor | Solid copper, Class 1 | Stranded copper, Class 2 (7 strands) | Fine-wire flexible copper, Class 5 |
| Max DC resistance at 20 degrees C | 7.41 ohm/km | 7.41 ohm/km | 7.98 ohm/km |
| PVC insulation | 0.8 mm | 0.8 mm | 0.8 mm |
| Outer diameter | about 3.4 mm | 3.3 to 4.0 mm | about 3.5 to 3.6 mm |
| Weight | about 30 kg/km | about 34 kg/km | about 30 to 34 kg/km |
| IEC equivalent | 60227 IEC 01 | 60227 IEC 01 | 60227 IEC 02 |
| Typical packing | 100 m coils | 100 m coils; 500 m on request | 100 m coils; 500 m or 1,000 m on request |
Note the resistance line. A Class 5 conductor of the same nominal size is allowed a slightly higher resistance than Class 1 or 2, because fine wires pack less efficiently and the nominal size is fixed by resistance, not by measured area. When the desk checks a sample, it compares the measured resistance with the limit for the class on the order, not with a generic figure for 2.5 mm2.
Where each one is installed
H07V-U is the simple choice for fixed wiring in conduit and trunking in smaller sizes, where the wire is pulled once and terminated in screw or spring terminals. It holds its shape, which some electricians like for neat panel work and some dislike for tight bends. Solid conductors are usually limited to the smaller sizes because a thick solid wire becomes difficult to bend and pull.
H07V-R keeps the rigid feel but uses a few strands, so larger sizes stay workable. Above the smaller sizes, a stranded Class 2 conductor is the normal form for fixed wiring, and the partner plant catalogue covers single cores from 1.5 to 400 mm2 in this family. In the reference 2.5 mm2 construction the conductor is seven strands with a diameter of about 2.01 mm under a 0.8 mm PVC wall, so the finished wire is barely larger than the solid version while being noticeably easier to dress into a board.
H07V-K is the flexible version, used where the wire must bend repeatedly during installation: inside distribution boards and control panels, in tight conduit runs and for connections to equipment that is fixed but needs routing around corners. It is still a cable for fixed installation, not a flexible cord for appliances; for moving equipment a sheathed cord such as H05VV-F is the right family, covered on the flexible cords page.
- Termination: fine-wire Class 5 conductors are commonly fitted with ferrules in screw terminals; ask your installer what the terminal maker requires.
- Pulling: H07V-K and H07V-R pull more easily through long or bent conduit than H07V-U of the same size.
- Retail: many retailers stock U or R in small sizes for house wiring and K for panel builders; check what your market actually buys before ordering all three.
Compliance points that are the same for all three
For sale in the EU, these cables are construction products when installed permanently in buildings, so they need a declaration of performance and CE marking under the Construction Products Regulation. The CPR class is declared on the DoP for each construction; for plain PVC single cores Eca is common, per the plant's datasheet. A harmonised HAR mark is a separate third-party approval held by the partner plant for that construction and checked in the certifier's public database per order. Conductor resistance, insulation thickness, spark or voltage test and print are the routine checks that matter most, and the CPR classes guide explains how the class letters read.
Current rating does not change between the three in the way buyers sometimes expect, and it is not something to read from a sales table. It depends on the installation method under IEC 60364-5-52 or the national wiring rules, and the project engineer confirms it.
How to order a mixed range
Distributors and retailers usually want a matrix: several sizes, several colours and one or two conductor classes. Each class and size is a separate production setting, so the minimum quantity is counted per size, class and colour, not per order. A useful way to build the list:
- List the sizes your market buys, usually 1.5, 2.5, 4, 6 and 10 mm2 for house and small commercial wiring.
- Choose U, R or K per size; many ranges use U or R for 1.5 and 2.5 mm2 and K for panel work.
- Set colours per size, including green-yellow for protective conductors.
- Fix coil length and coil packing, carton count and label text.
- State the market and standard so the print and DoP match.
The desk shortlists partner plants whose ranges cover the classes you need and checks sample resistance per class before quantities are booked. MOQs and lead times are typical ranges confirmed in writing for each order, as described on the MOQ and lead time page. Send the matrix through the quote form and the building wire line will be matched to the plant that fits it.