Which power supply should I select for my KNX system?
To choose a proper power supply for a KNX installation, you must take into account the devices consumption at 29 VDC with a security factor of 1,5 in order to cover future project extensions.
Line with 30 KNX devices. Supposing an estimated consumption of 10 mA per device, the total line consumption would be 300 mA.
Applying a security factor of 1,5, the chosen power supply should supply more than 300*1,5=450mA. Therefore, the correct election would be a 640mA power supply.