Altough having found a lot of documentation concerning wiring of I²C buses, I'm still not sure about the following question:
If both devices use separate power sources, is it a good idea to connect VCC/GND of those two devices?
I have two lines for SCL and SDA, connected to SCL/SDA pins on both devices A and B. The master device's VCC is connected to both lines using a pull-up resistor. Now as far as I understood, VCC/GND of the two devices should not be disconnected but I'm afraid I'd damage something if I'd connect them. As two separate power sources will never provide exactly the same voltage that would result in high currents, won't it? Or should I just connect them using some resistor to avoid high currents but provide the same voltage level?