Hi,

Just wondering what advice people have on the best way to reliably join two lengths of Cat5e cable. 

I have some solid core armoured Cat5 running about 8 meters out to a pair of 20,000L underground water tanks. The cable comes up through a sleeve in the foundation and was left disconnected behind a blank wall plate.  There is a second solid core Cat5e cable behind the blank faceplate running about another 8m back to the 'storage' room where it's terminated with a single RJ45 faceplate rather than on the patch panel so as not to be confused with the normal network runs.

The reason for having all of this is to remotely monitor the water level in the tanks using an HC-SR04 ultrasonic transducer mounted on the tank ceiling to measure the distance down to the water surface.  I was planning on putting just the transducer in the tank, and an Arduino back in the storage room.  Alternatively I could put both the Arduino and transducer in tank and power it using PoE.

Any recommendations on the best way to join these two cables, or the merits of having the Arduino in the tank with the sensor rather than back in the less hostile environment of the storage room would be appreciated.