I’m planning to install opensprinkler in my farm. I’d like to be able to launch 5 to 6 simultaneous valves at the same time, some of them situated 250 meters away.
I bought a 6A transformer.
Which wie gauge should I use for the common cable ? Taking into account loss of voltage, distance, and the number of simultaneous valves ?
I found info for one valve in the topic : What’s the maximum distance allowed between the controller and the valves? (https://opensprinkler.com/faq/#technical)
“300 m with 18 AWG wires”
And about two valves on rainbird description : https://www.rainbird.fr/produits/accessoires/cable-electrique
“350 m with 0,8mm2 wire for one valve, 175m for 2 valves.”
Could somebody help me with the calculation for 5 to 6 ? I was planning to use 2.5mm2 cable for the common wire, but I’d appreciate to be advised.
18 to 20 AWG should be sufficient for each zone wire. You are correct that in your case the common wire needs to be thick, because if you plan to run several vales at the same time, the entire amount of current has to run through the common wire, but the return path is through each zone’s corresponding zone wire, so the common wire needs to be quite thick. I believe 2.5mm^2 is sufficient for common. You can always use parallel connection to combine several thin wires to achieve the effect of a thicker wire.