Arduino pushbutton max cable length
Well, if the shielded cable is 22AWG, the resistance/meter is about 0.053 ohms. Multiplied by thirty is 1.59 ohms. Assuming the HUGE input draw of the I/O pin of 1mA, the voltage drop accross the circuit would be 1.59R x 0.001A. This would be a drop of 0.00159V. You should be fine running the cable for 30 meters and beyond :)