2-Core vs 4-Core KNX Cables: Choosing the Right Option for Smart Building Installations
When designing a KNX smart home or building automation system, selecting the right cable type is crucial for reliable communication and long-term scalability. The most common options are 2-core and 4-core KNX cables, each serving a different purpose.
2-Core KNX Cable
A 2-core KNX cable contains a single twisted pair of conductors. This pair carries both the KNX data signal and the 30 V DC bus power required for devices on the network.
It is simple and cost-effective for small installations but offers no spare conductors for expansion or auxiliary power. It is not the official KNX-standard cable and is mainly used in limited or retrofit applications where only one pair is needed and no future upgrades are planned.
4-Core KNX Cable (2 × 2 × 0.8 mm)
The 4-core KNX cable is the standard and recommended option for KNX systems. It consists of two twisted pairs, typically color-coded red/black and yellow/white.
The red/black pair carries KNX communication and bus power, while the yellow/white pair can be used for future expansion, auxiliary power (24 V DC), or a second KNX line.
Because it provides flexibility, better noise immunity, and easier maintenance, the 4-core cable ensures a future-proof installation that complies with KNX guidelines.
Which One Should You Choose?
For all new installations, the 4-core LSZH (Low Smoke Zero Halogen) KNX cable is strongly recommended. It offers improved safety, flexibility, and compliance with building standards, making it ideal for both residential and commercial smart building projects.
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