OMY, OWY and OMYp – what is the difference?
OMY, OWY and OMYp differ in rated voltage, shape, number of cores and range of cross-sections. We break down both the Polish symbols and the harmonised H03VV-F, H05VV-F and H03VVH2-F.
OMY, OWY and OMYp are three flexible cables with PVC insulation and sheath that differ in the rated voltage of the cable, the shape, and the available number of cores and range of cross-sections: OMY and OMYp are rated 300/300 V, OWY 300/500 V, and OMYp is the only one made in a flat version. The symbols H03VV-F, H03VVH2-F and H05VV-F are the same products written in the harmonised designation system, so the question of what H05VV-F means comes down to reading the successive characters of the code. Below both notations are broken down into parts, together with a comparison of the parameters from the product pages.
What the letters in OMY, OWY and OMYp mean
The Polish symbol describes the construction and the version of the cable, letter by letter:
- O — insulated conductors enclosed in a common outer sheath; in Polish commercial practice such a cable is called “oponowy”. All three types have a PVC outer sheath.
- M — household version: OMY and OMYp.
- W — workshop version: OWY.
- Y — conductor insulation and sheath of polyvinyl chloride, that is PVC.
- p — flat shape; without this letter the cable is round.
Hence the answer to what an OWY cable is: a round cable in the workshop version, with PVC insulation and sheath, rated 300/500 V. An OMY cable reads the same way — the same construction in the household version, rated 300/300 V — and OMYp is its flat counterpart.
Harmonised designations: H03VV-F, H05VV-F and H03VVH2-F
The harmonised code is read character by character, and each of its elements corresponds to a parameter given on the product page:
- H — a product in the harmonised version.
- 03 and 05 — the rated voltage of the cable: 03 is 300/300 V, that is OMY and OMYp, and 05 is 300/500 V, that is OWY.
- VV — PVC twice: the first letter denotes the conductor insulation, the second the outer sheath.
- H2 — flat construction; in this comparison it appears only in OMYp.
- -F — a flexible, stranded conductor. Every one of the three types has it.
An OWY cable and an H05VV-F cable are therefore the same product, just as OMY and H03VV-F are. Both notations are given side by side in the collection names and on the product pages, so that the documentation and the order describe the same thing.
It is worth avoiding a common misunderstanding here: the rated voltage, 300/300 V or 300/500 V, is a parameter of the cable itself, not of the circuit or the installation. Installations in Poland work at 230/400 V. Which rated voltage is required in a particular connection follows from the appliance's documentation and from the operating conditions of the circuit.
Comparison: voltage, shape, cross-sections and application
| Parameter | OMY | OMYp | OWY |
|---|---|---|---|
| Harmonised designation | H03VV-F | H03VVH2-F | H05VV-F |
| Rated voltage of the cable | 300/300 V | 300/300 V | 300/500 V |
| Shape | round | flat | round |
| Conductor | copper, flexible (stranded) | ||
| Insulation and sheath | PVC; sheath black or white | ||
| Cores in the range | 2, 3, 4 | 2 | 2, 3, 4, 5 |
| Cross-sections in the range | 2× and 3×: 0.5–1.5 mm²; 4×: 0.5–0.75 mm² | 2×: 0.5–1.5 mm² | 2×: 0.75–2.5 mm²; 3×: 0.5–4 mm²; 4× and 5×: 0.5–6 mm² |
| Operating temperature | −30…+70 °C when permanently laid, −10…+70 °C with mobile equipment | ||
| Product standards | PN-E-90103:1991, PN-EN 50525-1:2011; core identification to PN-HD 308 S2 | ||
| Packaging | 100 m coil | ||
Core colours — separately for each type
Core identification is given on the product pages separately for each type and is not common to all three:
- OMY — 2-core: blue, brown; 3-core: blue, brown, green-and-yellow; 4-core: brown, green-and-yellow, black, grey.
- OMYp — 2-core: blue, brown.
- OWY — 2-core: blue, brown; 3-core: brown, blue, green-and-yellow; 4-core (with PE): black, brown, green-and-yellow, grey; 4-core (without PE): black, blue, brown, grey; 5-core: black, blue, brown, green-and-yellow, grey.
The two-core versions have no protective conductor. A green-and-yellow conductor appears in OMY in the three- and four-core versions, and in OWY in the three- and five-core versions and in the four-core variant with PE — four-core OWY has two colour schemes. Green-and-yellow is reserved exclusively for the PE protective conductor: under PN-HD 308 S2, the core identification standard given on the pages of all three types, it must not be used as a live conductor, whether line or neutral. Because four-core OWY has two colour variants, the core identification should be checked on the actual product before connection, not assumed from the type alone.
When to choose OWY, and when OMY or OMYp
OMY versus OWY: what actually differs
The comparison of OWY and OMY rests on three parameters from the product pages: the rated voltage of the cable (300/500 V against 300/300 V), the available number of cores (from 2 to 5 against 2 to 4) and the range of cross-sections (up to 6 mm² against 1.5 mm²). OWY is also the only one of the three types available in a five-core version. Which set of parameters is required in a given connection follows from the documentation of the load and from the operating conditions of the circuit — this is assessed on site by an electrician.
What an OWY cable is for
The OWY product pages give as the application use in homes, kitchens and offices, and household appliances, including those working in damp environments under medium duty, for example washing machines and refrigerators. They also list kitchen appliances and heating equipment. These are indoor applications: the pages do not cover work outside the building or laying in the ground.
When OMY is enough, and when OMYp is needed
The OMY and OMYp pages give the same application: mobile and portable electrical equipment — small household appliances, radios, table and floor lamps — in homes, kitchens and offices. Both types have the same rated voltage and the same range of cross-sections, from 0.5 to 1.5 mm². What differs is the shape and the available number of cores: OMYp is stocked only as two-core, so where a protective conductor is needed OMY in the three- or four-core version remains. With two cores the choice between them comes down to the shape.
What these three cables do not replace
OMY, OWY and OMYp have a stranded conductor and are cables for connecting loads. A permanently laid installation, surface-mounted or concealed, uses installation cables with a solid conductor — YDY and YDYp. The difference lies in the construction of the conductor: a stranded one withstands repeated bending, a solid one is intended to be laid and left still.
Cross-section and number of cores — what decides the choice
There is no single universal figure here. The required cross-section is affected by the current drawn by the load, the length of the run, the way the cables are laid and bunched, the ambient temperature, the permissible voltage drop and the protection of the circuit — the same cross-section has a different current-carrying capacity under different conditions. The number of cores depends on whether the load requires a protective conductor and on whether the circuit is single- or three-phase. Choosing the type of cable, the cross-section, the number of cores and the protection for a specific load and specific conditions is the job of the electrician carrying out the installation.
The full list of cross-sections and core counts in the range is in the collections: OWY workshop cables (H05VV-F), OMY household cables (H03VV-F) and OMYp cables (H03VVH2-F). An example of a product page with a full parameter table is OWY 3×2.5 300/500 V. All three types are sold in 100 m coils, with a black or white sheath.
Questions about product parameters are best asked through the form on the Contact page — that route directs them to the technical specialists. You can also call the support line: +48 669 055 666, service in Polish, Monday to Friday 8:00–15:00. Wholesale and bespoke orders are taken by the sales department — on the same number in Polish, and on +48 607 496 325 in Polish and Ukrainian, 8:00–15:00 (CET).
