simonB2013:
Good Q's !Conductor arrangement is not finalised as I am trying to make it modular.
In reality, there maybe a 12meter loop with 4 sensors; and 2 spurs with 1-2 sensors each, 1 of 4 meter, the other of 2 meter.
I'll work in parallel where possible.Current: for each sensor I am expecting .120ma with peak .200ma (no data sheet - working of other user's comments until I can measure for myself)
Arduino location will not significantly add to the distances mentioned above, 0.5m maxmum.
Cable will be routed along a mixture of terrain : along walls, behind strips of wood; and buried if possible.
I've used some neoprene covered speaker cable (twin with shielding) outdoors. It's carrying 14V AC at about 1A. Much of it (about 5 Mtrs) is buried inside a length of garden hose (to prevent someone putting a spade through it!). The rest is cable-clipped to wood and brick. The inside of the junction box was given a good spray of WD40 before the lid was screwed down. It's been in over a year with no problems.