Controller Wires

Discussion in 'Irrigation' started by PurpHaze, Oct 1, 2005.

  1. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    We use strictly 14AWG solid copper insulated direct burial wire for our runs. When I helped my dad automate his house's system after mom passed away four years ago I used a bundled 20-22 gauge (can't remember; got it at OSH) to run between the controller and valves. We use the 14AWG simply because of the length we can run and the least resistence over those lengths.

    Three questions:

    1. What do you guys run on typical residential/small installs?

    2. What do you guys run on typical commercial/large installs?

    3. Is there a specific wiring code in your area for irrigation control wires?

    We have developed one of our own which follows. Of course we buy wire by the 2500' spool and dispense it from an in-house fabricated caddy that can be wheeled around to run start locations.

    White: common

    Red: primary valve control

    Blue: spare common (looped up into every valve box)

    Orange: spare valve control (number varies depending on number of valves in a particular direction of wire travel; can have as many as 8-10 come into the controller junction box below the controller; looped up into every valve box)

    This was developed after years (50's to 80's) of systems being put in without spare wires and then getting butchered by gophers or ground squirrels. These spare wires have saved the day on many systems as they allow quick repair. We can then go in with the 521 and ground fault locator to repair wiring during the off-season.

    Appreciate any thoughts.

    Hayes :waving:
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,887

    I dunno, you can use heavier gauge wires, and have extra conductors and all, but along comes a backhoe, and it's all over, and hopefully you had color-coded wires.

    With solenoids consuming less power than before, 18 gauge irrigation cable can handle the load, even on small commercial jobs. I'd stick with that until the runs exceeded 500 feet, and then, I'd only go to a 14 gauge common, with the 18 gauge irrigation cable for the zone valves. Runs beyond a thousand feet could go to 14 gauge throughout.
  3. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    This is why we run 14 gauge throughout. If our systems aren't that long of a run yet they will be in the future. We're often confronted with phasing in sections in the future so the controller, mains and wiring [increased number; ending at a makeup box (Christy F-8 or G-5 with cast iron lid and poured concrete collar) noted on an as-built where main is capped for expansion] are oversized. We try to outguess what will occur in the future and often are immediately ready when expansion occurs.

    Hayes :waving:
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,887

    Hopefully, you have some limit to the expansion of the system, since 14 gauge wire limits you to little more than 2000 feet. At some point, I would expect the cost of copper wire would lead to the use of satellite controllers.
  5. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    For all the "edu-speak" of getting students ready for THIS century our district has some problems bringing irrigation technology into the LAST century.
  6. jerryrwm

    jerryrwm LawnSite Bronze Member
    Messages: 1,274

    Boots I gotta disagree with you on the max length for 14 ga wire.

    Check a Weathermatic catalog. They have a wire sizing chart based on static pressure and incoming voltage to the transformer. With 75 psi and 115 volts to the transformer running one valve per station you can run 3957'' on the LM series controller. If running two valves you can run 1453'.

    If longer distances are needed, you can increase the common and get longer distances.

    Now, is running 1/2 a mile from the controller prudent? Not if you're the one doing the service walk-thru. Especially if you don't have a remote like a TRC or RainMaster and didn't program enough time on the controller.

    Golf courses use a lot of 14 and 12 ga wire and they have some pretty long wire runs for the tees and greens controllers.

    Now how about those that insist on using 18 ga multistrand on commercial projects? Big pet peeve of mine.

  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,887

    <a href=>Hunter has this chart</a> that gives a lower number, but it assumes 150 psi, and higher pressure demands more power to a solenoid. The 24VAC figure may also figure into the lower distances, since most modern controllers have slightly higher voltages. I think old Weathermatic solenoids could operate on 12 Volts DC, but at 75 psi maximum static pressure.
  8. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Messages: 2,781

    Electricity ain't my bag, and it probably never will be, but I was taught that splices count against the total run. A half mile run for 14 ga is probably fine for most modern equipment, but if the common is spliced x number of times in that half mile, it probably should be 12ga. I use 18 multi on residential jobs. On large residential, I've used both 16 and 14. For commercial work with large controllers, I like 14. Color coding is great if you can get away with it. Look at a catalog, they make 14uf in more colors than 18/13. White common, black MV, if I can locate the controller to split the runs, then depending on the number of zones and total amount of zone wire, buy different colors. Spares are always different. I like two spares each direction regardless of wire size. If I am installing a 6-12 zone residential, try to center the controller and run 2 or more spares each way. If a MV is asked for or bid, use an alternate spare for the MV's common. And w/ a 14UF common, you can run 1000' from the controller according to the charts. I still want to know what 6 - 10 splices does to that distance. It will probably work through the warranty regardless, but as wire and solenoids age, I would think you would be responsible for creating a problem if you designed at the chart maximum.
  9. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    Mine neither... I don't calculate resistance and wire runs I just know what has worked in the past. I think the longest run I can think of in our district is 1/4 mile and that system has been working for 35 years, except when the occasional gogher interrupts the wiring.

    I believe that every splice causes some amount of resistance (just like a change of direction in pipe causes pressure loss) and affects the overall length of run by shortening it appropriately.
  10. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    At 150 PSI the chart will err on our side as installers.

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