KNX cable India projects should use cable that is sold and specified for the KNX bus, because every device on a line takes its power and its data from the same twisted pair. The commonly named types are YCYM 2 x 2 x 0.8 and J-Y(St)Y 2 x 2 x 0.8, and the cable's datasheet should say it is suitable for KNX. This post explains why the type matters and what to check on the drum.
What does the KNX bus cable carry?
A KNX twisted-pair line uses one pair of conductors for both power and data. A KNX power supply in the distribution board feeds the line at 30 V DC SELV, and every device on the line draws its power from it while talking on the same pair. The cable is therefore part of the system's electrical design, not a loose accessory. Our KNX cable guide gives the line limits: up to 64 devices with a 640 mA supply, up to 350 m from the supply to the furthest device, 700 m between any two devices and 1,000 m in total.
Which cable types are named for KNX?
ABB's KNX system manual names YCYM 2 x 2 x 0.8 and J-Y(St)Y 2 x 2 x 0.8 as examples of cable suitable for the bus. Both are shielded cables, and the figures 2 x 2 x 0.8 mean two pairs of two conductors, each 0.8 mm in diameter.
The name is only part of the answer. J-Y(St)Y is a general designation for a shielded, PVC-insulated communication cable, and a cable with that name is not automatically a KNX bus cable. Check that the datasheet states suitability for KNX or EIB, and compare the electrical details with the manufacturer's KNX recommendation.
What should the datasheet say?
- KNX or EIB suitability, stated. The datasheet names the KNX bus as an intended use.
- The conductor. A solid conductor of 0.8 mm, because KNX bus terminals are specified for single-wire conductors of 0.6 to 0.8 mm.
- Insulation and test voltage. Compare the figure with the manufacturer's recommendation. As one example, Legrand lists its KNX bus cable, reference 049292, with 4,000 V insulation.
- Shielding and sheath. The datasheet should describe the screen and the sheath material. Many KNX bus cables have a green sheath, but colour is a habit and not a guarantee, so read the datasheet and not the colour.
We suggest keeping the drum label or the datasheet with the project file, so the next person knows what is in the wall.
Why is Cat6 not a substitute?
Spare network cable is the most common shortcut. Cat6 is made for network data, and its conductors are generally thinner than the 0.6 to 0.8 mm solid conductor that KNX bus terminals are specified for. ABB's recommendation is a certified KNX bus cable, and Cat6 is not one. Use Cat6 for the network and KNX cable for the bus. We covered the difference in the KNX cable guide.
| KNX bus cable | Cat6 network cable | |
|---|---|---|
| Made for | The KNX bus: power and data on one pair | Network data |
| Conductor | Solid, 0.8 mm in the recommended 2 x 2 x 0.8 types | Generally thinner than 0.6 to 0.8 mm |
| Recommended for KNX | Yes, when the datasheet states KNX or EIB suitability | No |
Why should bus and mains not share a box?
The bus is a low-voltage circuit and mains is not. A box that carries both puts a safety-critical separation in the hands of whoever opens it next. How the two are separated in conduits and in wall boxes is a matter of the electrical code that applies to your project and of your integrator's method, so ask for it to be written down before the wiring starts.
- Keep the bus cable and mains cable in separate conduits where your installer's method calls for it.
- Use the red and black KNX bus terminal and strip about 5 mm of the single-wire conductor.
- Use a differently coloured sheath for any second 30 V DC auxiliary supply cable, so that the two are not mixed up.
- Label both ends of each cable with the line number.
What should you do on a new build?
Put the cable type on the electrical drawing, buy it from a source that supplies the datasheet, and ask the electrician to keep off-cuts and the drum labels until commissioning is done. If your supplier cannot give you a datasheet for the cable, ask for another one. A cable that nobody can document is a risk you take on for the life of the building.
Questions people ask
Can I use Cat6 for the KNX bus?
It is not a recommended KNX bus cable. Its conductors are generally thinner than the 0.6 to 0.8 mm solid conductor that KNX bus terminals are specified for. Use a KNX-certified bus cable for the bus.
Is any green cable a KNX cable?
No. Many KNX bus cables have a green sheath, but the colour does not prove the specification. Read the datasheet.
Is J-Y(St)Y 2x2x0.8 the same as KNX cable?
It is named by ABB as an example of a cable suitable for the bus, but the designation is general. Check that the datasheet states suitability for KNX or EIB.
Not sure which cable your integrator specified? Send us the length and the type and we will say whether we can supply it or point you to the right route: talk to our team.
Sources checked on 7 November 2026
- Morion Automation, KNX cable in India, for line limits, terminals and the Cat6 comparison.
- ABB, KNX system manual, for YCYM and J-Y(St)Y 2 x 2 x 0.8 as example cable types.
- Legrand, KNX bus cable, 2 pairs, 500 m, ref. 049292, as an example of a stated insulation rating.
KNX cable India projects should use cable that is sold and specified for the KNX bus, because every device on a line takes its power and its data from the same twisted pair. The commonly named types are YCYM 2 x 2 x 0.8 and J-Y(St)Y 2 x 2 x 0.8, and the cable's datasheet should say it is suitable for KNX. This post explains why the type matters and what to check on the drum.
What does the KNX bus cable carry?
A KNX twisted-pair line uses one pair of conductors for both power and data. A KNX power supply in the distribution board feeds the line at 30 V DC SELV, and every device on the line draws its power from it while talking on the same pair. The cable is therefore part of the system's electrical design, not a loose accessory. Our KNX cable guide gives the line limits: up to 64 devices with a 640 mA supply, up to 350 m from the supply to the furthest device, 700 m between any two devices and 1,000 m in total.
Which cable types are named for KNX?
ABB's KNX system manual names YCYM 2 x 2 x 0.8 and J-Y(St)Y 2 x 2 x 0.8 as examples of cable suitable for the bus. Both are shielded cables, and the figures 2 x 2 x 0.8 mean two pairs of two conductors, each 0.8 mm in diameter.
The name is only part of the answer. J-Y(St)Y is a general designation for a shielded, PVC-insulated communication cable, and a cable with that name is not automatically a KNX bus cable. Check that the datasheet states suitability for KNX or EIB, and compare the electrical details with the manufacturer's KNX recommendation.
What should the datasheet say?
- KNX or EIB suitability, stated. The datasheet names the KNX bus as an intended use.
- The conductor. A solid conductor of 0.8 mm, because KNX bus terminals are specified for single-wire conductors of 0.6 to 0.8 mm.
- Insulation and test voltage. Compare the figure with the manufacturer's recommendation. As one example, Legrand lists its KNX bus cable, reference 049292, with 4,000 V insulation.
- Shielding and sheath. The datasheet should describe the screen and the sheath material. Many KNX bus cables have a green sheath, but colour is a habit and not a guarantee, so read the datasheet and not the colour.
We suggest keeping the drum label or the datasheet with the project file, so the next person knows what is in the wall.
Why is Cat6 not a substitute?
Spare network cable is the most common shortcut. Cat6 is made for network data, and its conductors are generally thinner than the 0.6 to 0.8 mm solid conductor that KNX bus terminals are specified for. ABB's recommendation is a certified KNX bus cable, and Cat6 is not one. Use Cat6 for the network and KNX cable for the bus. We covered the difference in the KNX cable guide.
| KNX bus cable | Cat6 network cable | |
|---|---|---|
| Made for | The KNX bus: power and data on one pair | Network data |
| Conductor | Solid, 0.8 mm in the recommended 2 x 2 x 0.8 types | Generally thinner than 0.6 to 0.8 mm |
| Recommended for KNX | Yes, when the datasheet states KNX or EIB suitability | No |
Why should bus and mains not share a box?
The bus is a low-voltage circuit and mains is not. A box that carries both puts a safety-critical separation in the hands of whoever opens it next. How the two are separated in conduits and in wall boxes is a matter of the electrical code that applies to your project and of your integrator's method, so ask for it to be written down before the wiring starts.
- Keep the bus cable and mains cable in separate conduits where your installer's method calls for it.
- Use the red and black KNX bus terminal and strip about 5 mm of the single-wire conductor.
- Use a differently coloured sheath for any second 30 V DC auxiliary supply cable, so that the two are not mixed up.
- Label both ends of each cable with the line number.
What should you do on a new build?
Put the cable type on the electrical drawing, buy it from a source that supplies the datasheet, and ask the electrician to keep off-cuts and the drum labels until commissioning is done. If your supplier cannot give you a datasheet for the cable, ask for another one. A cable that nobody can document is a risk you take on for the life of the building.
Questions people ask
Can I use Cat6 for the KNX bus?
It is not a recommended KNX bus cable. Its conductors are generally thinner than the 0.6 to 0.8 mm solid conductor that KNX bus terminals are specified for. Use a KNX-certified bus cable for the bus.
Is any green cable a KNX cable?
No. Many KNX bus cables have a green sheath, but the colour does not prove the specification. Read the datasheet.
Is J-Y(St)Y 2x2x0.8 the same as KNX cable?
It is named by ABB as an example of a cable suitable for the bus, but the designation is general. Check that the datasheet states suitability for KNX or EIB.
Not sure which cable your integrator specified? Send us the length and the type and we will say whether we can supply it or point you to the right route: talk to our team.
Sources checked on 7 November 2026
- Morion Automation, KNX cable in India, for line limits, terminals and the Cat6 comparison.
- ABB, KNX system manual, for YCYM and J-Y(St)Y 2 x 2 x 0.8 as example cable types.
- Legrand, KNX bus cable, 2 pairs, 500 m, ref. 049292, as an example of a stated insulation rating.
