The electric field emitted by the sensors extends 5 cm out from the edge of the probe so you must have at LEAST that distance between your probe and any other object. A little more would be better. If your sensors are being excited and read simultaneously you will have to keep them 10 cm apart or they will interfere with each other and your data will be crazy.

Note: All of our other sensors require only 2 cm of distance between the sensor and other objects.