I²C info

Ideally, you don't use twisted pair at all. Twisted pair is useful for balanced signals. If you don't have any other cable, twist signal with ground. If you really only have four wires, think about how much power the remote end consumes - you may end with a higher-than-tolerable ground offset - before committing to using only one wire for GND. I usually use old Cat5 cable (not higher! the double shield adds capacity you don't need) with:

• one pair ground
• one pair +5V
• SDA & GND pair
• SCL & GND pair

For longer distances you should use a repeater, a I²C extender. For example a P82B715 from Texas Instruments.