Doing your first KNX Project? Read This!

Planning

Planning out what your client wants is probably the most important step to every KNX project even more so then regular electrical projects, this is mainly because there are so many elements that can be incorporated into the system and to get everything to working together seamlessly it can take some extra steps.

Things to think about when planning & prewiring the project:

• What does the client want out of a smart home? Remote access, Audio/Visual, Heating integration, Timers and schedules to create automations, Blind control ETC.
• Maybe they want more things than is allowed within their budget, so we have to think about what needs to be done at the initial fit off and what can be done at a later date. For example, things like feature lights, Curtains, integrating heat pumps (if indoor unit is accessible), Audio Visual, Dimmers and Outdoor things can be prewired but do not need to be installed initially, whereas things like Underfloor heating control, Switch locations, Motorized blinds, Intercoms & Panels are usually best to get done initially as they’re less accessible post GIB.
• Once you’ve agreed on what the client wants initially and what they would like the option to add at a later date figure out what you need to do to prepare to add them in later. For example, Feature lights will need a dedicated feed from the switchboard that you can coil in the roof or wall, Curtains need a 4 core and a KNX cable in the wall next to the window or door where the motor will be positioned, Heat pumps will need a KNX cable to the Indoor unit, It is also good practice to run a KNX cable to an outdoor PowerPoint in case they would like to add some exterior lighting at some point, Gates & Garage doors need a contact cable run to the switchboard so it can be switched with a KNX relay along with any power needs. If in unsure feel free to reach out.
• Count out how many individually switched circuits will be controlled by KNX so you know what size relays you need (usually come in 4,8,12,16 & 24 ways) & allow enough space in the switchboard for this.
• Take measurements and videos of anything that you may require help finding when it comes to fitting off.
• Separate all the lighting feeds to one side of the switchboard for an easier time when installing the relays (as shown in photo below)

Tips:

• If you have a cable roller you can usually run multiple dedicated lighting circuit feeds at once to speed up the process, just make sure to label each end.
• KNX cables can be run in daisy chains but its best practice to have at least 2 feeds coming from the switchboard, if you’re installing a Panel that require auxiliary power (yellow and white cores) is usually best practice to run a direct feed for those or you will have to join the cores at any point where the cable is cut before the panel.
• If unsure about placement you can leave an uncut coil of KNX cable in the wall (for panels and switches etc)
• If client wants remote access run a Cat 6 to the main KNX panel and a KNX cable to the data board.
• For larger houses it can sometimes be more cost effective and quicker to do dali lighting and integrate it into KNX at the switchboard.
• Press mech switches can do a short press function and a long press function, so each switch can do 2 functions, dimming is usually programmed on the long press same with blind control (with short press being stop)
• With automated blinds you can usually ask the blind supplier to supply the leads at the prewire stage so you can join them onto the 4 core in the roof for a cleaner finish
• Automated blinds need to be “Dumb Motors”
• If integrating cameras into KNX Dahua works best. TVT can have issues
• Check out our Training hub for some visual installation guides

Fit Off Tips:

• Its easiest to do the live feed loops for the relays before mounting on the din rail (loops as shown in image above)

and that’s about it, the fit off is straight forward and similar to a regular fit off. if you’re outsourcing the programming make sure to write down where each switch interface is and keep an accurate list of the relay channels to save on programming costs.

Please reach out to us for any questions or if you require help programming.