But two-wire is hardly new. It\u2019s been around more than 20 years and has become the go-to system for large commercial sites. Still, two-wire may be new to you and to a lot of other contractors who have mainly installed conventional irrigation systems.<\/p>\n
\u201cContractors that have only worked on conventional who suddenly inherit a two-wire can definitely be afraid of it,\u201d says Grenert. \u201cThey think it\u2019s so intimidating, so technology-dense that they don\u2019t even want to pursue it.\u201d<\/p>\n
You can\u2019t blame a guy for sticking with what he knows. That strategy may not work forever, however, because two-wire is making inroads into the residential irrigation space.<\/p>\n
There are other reasons why some contractors shy away from two-wire. \u201cCost is one,\u201d says Dave Shoup, senior product manager, central control systems for Hunter Industries<\/a>, San Marcos, California. \u201cThe price of entry has been high. Not many contractors do projects large enough to justify it. Two-wire as a straight-up alternative to conventional wire has traditionally only made sense or allowed a contractor to break even at a certain system size.\u201d<\/p>\n But contractors do like the flexibility of being able to add stations at will without trenching back to a controller or running a bundle of wires.<\/p>\n The big trick with a decoder-based system, says Shoup, is that it depends on a really good installation. \u201cWhat happened when two-wire first came out is some guys just sort of jumped in. They\u2019d been wiring sprinklers the same way for 25 years, so they didn\u2019t necessarily pay attention to the stricter requirements, and they got burned. Mystery problems on a new installation? Nobody wants that.\u201d<\/p>\n It\u2019s like the first time you tried sushi. If it gave you a tummy ache, it was probably the last time, too. When our initial experience with something is poor, it\u2019s human nature to walk away and never look back. But a lot changes in 20 years. You aren\u2019t using the same computer you used back in 1999, are you?<\/p>\n Two-wire systems are either easier to install than conventional systems or harder, depending on whom you talk to. Which part of the installation you\u2019re talking about also makes a difference.<\/p>\n A conventional system has a wire going out to each valve plus a common. Every valve has the hot wire plus a common wire going back to the controller. For a 24-zone system, there\u2019d be 24 wires plus a common for every zone.<\/p>\n In a two-wire system, the two wires coming out of the controller are hooked up to a decoder placed at the first valve. These same two wires are then connected to the next decoder and valve combination, and the next and the next. As you can see, much less wire is needed.<\/p>\n \u201cWhat\u2019s the best thing about two-wire systems?\u201d asks Grenert. \u201cThere are only two wires. What\u2019s the worst thing about two-wire systems? There are only two wires. All that data has to come down the same two wires.\u201d That makes the installation simpler but at the same time, more exacting.<\/p>\n Keith Schweiger, CID, CLIA, CIC, CIT, CLWM, lands on the \u201ceasier\u201d side of the debate. Now a key account manager at SiteOne Landscape Supply<\/a> in Englewood, Colorado, he spent many years prior to that installing both conventional and two-wire irrigation systems.<\/p>\n \u201cTwo-wire is easier for a couple reasons,\u201d he says. \u201cMost of the work is trenched, so the wire can go right into the ground. You don\u2019t need to know today exactly how many zones you\u2019re going to need to run tomorrow. With a conventional system, you need to know that, because you have to install individual wires for all of them.\u201d<\/p>\n Two-wire has more flexibility to adapt to changing conditions. \u201cThe fact that I only have two wires to make my connections is, to me, one of the best things about two-wire systems,\u201d adds Schweiger.<\/p>\n But they are a tad touchy. Like millennials, two-wire systems are very sensitive.<\/p>\n \u201cThe copper wire has to be pristine, like jewelry; it can\u2019t have any dirt on it,\u201d says Mark Twiss, irrigation manager\/contractor at D.W. Burr Landscape and Design Inc.<\/a>, Sinsbury, Connecticut. \u201cEven a tiny nick in a wire can cause havoc.\u201d<\/p>\n A conventional system is a lot more forgiving. It can handle a bit of sloppiness in installation, where a two-wire system really can\u2019t. A higher level of craftsmanship is needed.<\/p>\n You\u2019ve heard the expression, \u201cWhen all else fails, read the instructions?\u201d That\u2019s never truer than it is with two-wire.<\/p>\n \u201cFirst and foremost, the most important thing is that you follow the manufacturer\u2019s specifications \u2014 that\u2019s critical, and they\u2019ll differ with every manufacturer,\u201d says Grenert. \u201cSome require a certain kind of wire versus others. When there are problems, it\u2019s often because you have someone installing a two-wire system the way he\u2019s always been comfortable.\u201d<\/p>\n Twiss points out that before two-wire systems, installers used 14-gauge single-strand wire for everything. \u201cEverybody used it and it didn\u2019t matter whose clock it was on. That\u2019s not the case with two-wire. The manufacturer\u2019s specs apply to using the proper wire, the proper connectors and the right installation technique to connect everything.\u201d<\/p>\n By \u201cthe right technique,\u201d Twiss means that every manufacturer stresses the need to make sure the wire connections are done properly. \u201cIn the old days you would strip your wires, grease them together and put them in the DBYs, and for the most part they worked pretty well,\u201d he says. \u201cThe old mechanical rotary 24-to-30-volt systems, you flipped a switch and they either worked or they didn\u2019t. They were very stout and reliable. You could get away with mistakes and the fault could literally take years to show up.\u201d<\/p>\n \u201cBut in two-wire decoder-based systems, the wire carries communications signals as well as power, so all of the wire connections have to be done both securely and properly.\u201d<\/p>\n There\u2019s another consequence to not following the manufacturer\u2019s specs. For instance, Tucor wants you to use its own brand of double-jacketed tin-coated copper wire on its two-wire systems. \u201cJust a little side note \u2014 if they don\u2019t use our wire, there\u2019s no warranty,\u201d warns Grenert, \u201cand the same is true of every manufacturer.\u201d<\/p>\n Another reason to follow the maker\u2019s specs to the letter \u2014 should you need another one \u2014 is that everything isn\u2019t completely uniform across all brands. \u201cIn the real world there is some intermingling of wire,\u201d Schweiger says. \u201cIt doesn\u2019t mean that a system will fail, necessarily. But you\u2019ll have much greater success if you follow the manufacturer\u2019s requirements. A lot of guys found out the hard way that they needed to pay a little bit more attention to the specs.\u201d<\/p>\n As was true for the wire, the same goes for the connectors, sometimes called splices, the little devices that link the solenoids to the system\u2019s wires. The exact ones they want you to use will be specified, too, usually 600-volt-rated waterproof DBRY-6 connectors, with exactly the right kind of waterproofing gel inside, and they\u2019ll come with instructions. \u201cYou do need to use the manufacturer\u2019s recommended connectors,\u201d says Schweiger.<\/p>\n Bad connections will create a host of problems. Sometimes they\u2019ll show up quickly and sometimes not for a while. But they will show up.<\/p>\n Other problems are caused by failing to think inside the box. \u201cAnything connected to the two-wire path must be installed inside the valve box, including the decoders,\u201d Grenert stresses. \u201cIf they\u2019re left outside, they\u2019re exposed to weather.\u201d<\/p>\n Grounding is especially vital with two-wire. It won\u2019t keep lightning from striking a system, but if it should get hit, proper grounding will minimize any damage.<\/p>\n Some systems require separate grounding decoders in every valve box; others connect directly to the rods.<\/p>\n \u201cWe\u2019ll ground the system right away at the point of connection with a 10-foot rod inserted into the ground 8 feet deep and put a surge protector and decoder on it,\u201d says Twiss. \u201cAbout 11 feet away from there, we\u2019ll insert a grounding plate approximately 30 inches down. Then we\u2019ll insert more grounding rods every 500 feet or so and another at the end of the line. That creates a kind of grounding umbrella that will protect the system.\u201d<\/p>\n The rods and plate are installed in line with the main decoder wire. Should Zeus throw a lightning bolt at the ground, the surge would be confined to one section between two grounding circuits, meaning that you\u2019d lose two decoders instead of 200.<\/p>\n Back to that pesky valve box \u2014 installers have differing opinions as to whether you need to place a grounding rod inside the valve box itself. Again, the safest course is to do what the manufacturer recommends. \u201cMark Grenert has always told us to do that, so I follow his point of view,\u201d says Twiss.<\/p>\n A 200-zone conventional system uses lots of wire, and copper isn\u2019t cheap. With less wire used, you save both time and labor.<\/p>\n But one of the reasons two-wire has mainly been used in commercial and some high-end residential applications is its higher cost. Each decoder costs around $150, so whatever you saved on wire can be spent on buying decoders. You\u2019ll also need copper rods and grounding plates. And two-wire controllers tend to be heavier duty and more expensive.<\/p>\n Two-wire has the edge when it comes to retrofitting. You have virtually unlimited flexibility to expand a system, anywhere you want, with no spare wires to run. \u201cIf a customer says, \u2018I\u2019d like to add two zones over here,\u2019 it\u2019s very easy to do that because you just add another couple of decoders to that wire, as long as your controller\u2019s not full,\u201d says Lyle Oulette, CIC, director of irrigation at Landscape Maintenance Services, Hillsborough, New Jersey.<\/p>\n Troubleshooting is less troublesome, too. \u201cUsing cable TV as an analogy, if half the block has its cable out, the problem isn\u2019t at every single house,\u201d says Schweiger. \u201cIt\u2019s likely to be one connection, and when that is fixed, all six subscribers will be back up and running.\u201d<\/p>\n Twiss thinks so. \u201cI have a 65-acre HOA community with multiple points of connection. We put in an ET- (evapotranspiration) based two-wire system, and it saved the community 6.7 million gallons of water valued at $28,000 to $30,000.\u201d<\/p>\n There\u2019s clearly money to be made installing two-wire systems. They open the door to bidding on big commercial projects with high profit potential. But before you venture into this world, \u201cget some training, and have your guys get training as well,\u201d advises Oulette.<\/p>\n Trodding the two-wire path may not be a simple journey, but it can be a road well worth traveling.<\/p>\n Hunter Industries, San Marcos, California, has launched a new two-wire irrigation product called EZDS for \u201ceasy decoder system.\u201d \u201cIt\u2019s a cost-effective two-wire system that isn\u2019t fussy, doesn\u2019t require special anything,\u201d says Dave Shoup, senior product manager, central control systems.<\/p>\n EZDS\u2019 main points of difference include:<\/p>\n Shoup says Hunter developed EZDS in response to a frequent contractor request. \u201cThey\u2019ve been saying, \u2018I have existing wiring already in the ground from a conventional system. I\u2019d like to use that wire to convert the system over to two-wire.\u2019 Now they can.\u201d<\/p>\n The EZDS system will work with the Hunter ICC2 controller and the Hydrowise HCC commercial controller, a Wi-Fi cloud-based control system that it shares a chassis with.<\/p>\n Intended for smaller commercial and high-end residential applications, the new system will accommodate up to 54 stations maximum. \u201cWe\u2019re clearly not aiming at mega-giant commercial sites with this product,\u201d says Shoup. \u201cThe idea is to broaden the base of the two-wire user pyramid. It opens up a whole new category of installations where a contractor may never have considered using two-wire before.\u201d<\/p>\n There are only two pieces, an output module and a new single-station decoder that is placed one per valve.<\/p>\n No special wire or connectors are specified, but it is suggested that only direct burial-rated wire be used. The gauge of the wire will determine how far you can go with it. \u201cYou can use 18-gauge wire that\u2019s left over for up to 900 feet in each direction; 14-gauge wire will get you to about 2,300 feet,\u201d Shoup says.<\/p>\n While the connectors are no longer specified either, installers are urged to use professional-grade waterproof ones.<\/p>\n Another big difference is that no inline surge protection grounding is required. But if you work in a lighting-prone area like Florida, it\u2019s advisable to add a surge arrestor.<\/p>\n The EZDM Output Module currently lists at $299 and the EZ1 decoders at $85 each. \u201cIt\u2019s a significant price breakthrough for a name-brand decoder system, and it means the break-even point for two-wire just got way lower,\u201d says Shoup.<\/p>\n Shoup says the EZDS system is not intended to supplant the existing two-wire systems sold by Hunter and other manufacturers, but to provide a lower-cost alternative for sites where two-wire had previously not been cost-effective or feasible.<\/p>\n<\/div>\n You can achieve installation two-wire installation without trepidation.<\/p>\n","protected":false},"author":28,"featured_media":3167,"parent":0,"template":"","main-categories":[27],"class_list":["post-3165","features","type-features","status-publish","has-post-thumbnail","hentry","main-categories-irrigation"],"yoast_head":"\nEasier? Harder?<\/h2>\n
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Quick facts about two-wire<\/h3>\n
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Ground the heck out of it<\/h2>\n
Pros and cons<\/h2>\n
Do they save water?<\/h2>\n
Simpler, cheaper, less fussy two-wire<\/h3>\n
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This article originally appeared in Irrigation & Green Industry magazine.<\/em><\/h6>\n
Mary Williams-Villano<\/strong><\/a> is a contributing editor to Irrigation & Green Industry and can be reached at pouncerspy@gmail.com<\/a>.<\/em><\/h6>\n","protected":false},"excerpt":{"rendered":"