Just google it online. 18 gauge is pretty much standard.
I've never seen 14 gauge used on a residential system.
14 gauge would support 15 amp AC circuits in a house.
Must be a real pain to work with, connect to terminals, etc.
Whoever used that must be a real knucklehead.
The sprinkler system probably uses less than 100miliamps to work the
valves. Look at the rating on
the wall transformer.