Why Does Your System Need Surge Protection?

Today’s electronic equipment and solid-state components are very vulnerable to voltagesurges –small or large. Electrical surges are by far the biggest cause of problems with electri-cal circuits. Damaging surges may be produced by lightning, pumps being turned on or off,the energizing or de-energizing of a transformer, or a power source short. A typical 120-voltpower line each year can have as many as 2,500 surges of over 6,000 volts.

“But I don’t have a lot of lightning in my area.”

While lightning is, in fact, more common in certain areas of the country, it happens every-where. Damage can be instantaneous. About half of all lightning strikes are 20,000 volts and20,000 amps, but strikes can exceed 100,000 volts and can travel three miles through theground. Each flash of lightning can contain as many as 45 strikes. The average region in theUnited States can expect two to 30 strikes per year within a square mile.

Irrigation systems are particularly susceptible because they have large amounts of wireburied in the ground that can attract lightning. While you cannot protect against a directlightning strike, you can protect against its indirect electrical energy with surge protectionand proper grounding.

Surge damage happens in the first few milliseconds of the surge. Because surges are so fast,even fuses, circuit breakers and GFIs are not quick enough to protect from the damage.

For Your System’s Protection…

The theory behind most surge protection is to provide a path of least resistance for electri-cal surges so they dissipate harmlessly in the ground. Such surge protection involves bothsurge arrestors and proper grounding.

Surge Arrestors – Varistors and Metal Oxide Varistors

Rain Bird uses varistors as surge arrestors because they are much faster than other productsavailable on the market today. Varistors “clamp” voltage that

Grounding and Surge Protection:The Shocking Truth

T e c h n i c a lN e w s l e t t e r

Special Issue Published by Rain Bird Sales, Inc. Turf Products Winter 2000

continued on next page

IN THIS ISSUE:Grounding

One-Inch Manifold Systems

Controller Energy Costs

Rain Bird ContestWin a FREE hat…see back for details

Keys to a Reliable Drip System

BOARD ASSEMBLY

RibbonCable

Terminal

Field Wire Thermal Strip GroundingTerminal

Ferrite Inductors

TransformerPower

Terminal

Fuse

M.O.V.’s

Triacs

exceeds a certain level and shunts theexcessive energy to a harmless path in theground.

An M.O.V. or Metal Oxide Varistor is a bilat-eral device (with no polarity) that is partic-ularly effective at redirecting surges. It issmall and easily mounts on PC boards. It isvery fast, can handle moderately highpower surges and is self-extinguishing.

Protection From the Ground Up – Your Grounding System

Grounding is the essential backbone of alightning protection system. No matterhow much you spend on surge equipmentand how much of it you install, it’s only asgood as the grounding system you connectit to.

Good grounding breaks up the electricalenergy of lightning then directs it to a pathto the ground that has less resistance thanthe path through the irrigation equipment.

Components of an effective grounding system include a grounding conductor,bonding connector or clamp, one or moregrounding rods, the soil in contact with theelectrode(s), and the surrounding earth.

Grounding Rod

The ground wire from the device you areprotecting to the grounding grid should beat least one wire size larger than any otherwire connected to the device. Rain Bird rec-ommends a number eight solid, bare cop-per wire .

A good grounding system has low resis-tance to electrical current. You want theground to be as close to 0 ohms in resis-tance as possible. Having 0 to 5 ohms isexcellent, 6 to 10 is good, 11 to 15 is mar-ginal, and anything over 15 is not effective.Rain Bird specifies 0 to 10 ohms for agrounding grid, or the system warranty is void.

Using soil additives and keeping theground moist with a dedicated sprinklercan reduce resistance and encourage energy to travel to the ground.

A soil moisture level of 17% offers the bestsoil conductivity. Soil resistance can also belowered by adding chemicals, but careshould be taken to avoid damaging surrounding landscaping.

Note: When a grounding grid is firstinstalled, you will be unable to get a trueohms reading because the rod surface willnot be in good contact with the soil. Wait 5to 6 weeks for a meaningful reading. Thencheck the grounds at least once a year.

As the new year begins, it’s a great time totell you each thank you for the hard workand dedication you put into servicing yourcustomers and representing Rain Birdfaithfully in 1999. Please take a bow. Youdeserve it.

I’ve seen the pride you take in your work.It’s a dedication that’s been reflected in theoutstanding results we’ve seen throughoutthe year. You’ve found creative ways tosolve problems, keep things green andmake customers happy. When the bar wasraised, you responded with enthusiasm,professionalism and integrity.

Here are a few of the highlights I’ll remem-ber from the year. The Rain Bird Turf andGolf Divisions held three ProfessionalImprovement Training Camps in 1999 withturnouts that exceeded expectations.Those who attended asked great questions,studied for tests, challenged the instruc-tors, and overall, gave very positive feedback on the class.

Looking back, I also want to thank the “veterans” of irrigation from throughoutthe country who have guided those new tothe industry this year. The newcomers haveappreciated both the value of your experi-ence and your willingness to share. It’s contributions like yours that will keep ourindustry moving ahead.

Finally, response to the Authorized ServiceCenter (ASC) Technical Newsletter andController Testing Program have been fantastic. I am also encouraged to see you taking advantage of the ASC WorkshopProgram by hosting training seminars forcontractors. This type of education willbuild a strong future for us all.

As the Rain Bird ASC Program prepares tomeet demands for the Year 2000 andbeyond, each of you shares the credit forour success. Your interest in the programreflects directly to the customers in the better service you provide. Thanks again, from all of us at Rain Bird, for a job well done.

Sincerely,Rod Waller - ASC Technical Services Manager

Editorial

by Rod Waller[ ]continued from front

THE RESISTANCE OF SOIL TYPES

Approximate earth resistance =

Soil type (ohms)

Loam 5-50

Clay 4-100

Sand/Gravel 50-1,000

Limestone 4-10,000

Shale 5-10,000

Sandstone 20-2,000

Granite 1,000

Slate 600-5,000

Conductor

Electrode

Earth contactSurrounding earth

Connector (clamp)

By Beatrice John, Product Manager

If you’re looking for more options and flexi-bility in the field, take a look at a few ofRain Bird's latest additions. These are justsome of the newest products available tomake design and installation more efficientand reliable for you and your customers.

NEW! One-inchManifold Systems

Eliminate the glue,mess and dryingtime in the field

with Rain Bird’snew pre-assem-bled manifoldsystems.Installation isquicker and easierwith this pre-

assembled system. Most importantly, eachmanifold system is pressure-tested afterassembly to ensure leak-proof operation.One-inch manifold systems are available intwo-, three-, four- and six-valve configura-tions. Models are also available with pre-installed slip outlet DV valves and directbury wire connectors for further installa-tion ease.

NEW! Pump -Start Relay (up to 5 hp) - UL Listed

Now you can combine reliable technologyand convenience with a UL listing. RainBird’s new R200 pump start relay activatespump motors of up to five hp and com-bines dependable relay technology fromSquare D with a UL listing. Most pump-start relays on the market are not UL list-ed. For yourconvenience,the R200includes sixwire nutswith the twolow- voltageand four

high-voltage leads, all pre-installed.

NEW! Turf Swing Joints - TSJ Series

Whether you’re looking for a one-inch orthree-quarter-inch size, Rain Bird’s newturf swing joints offer a convenient optionfor design flexibility. New one-inch swingjoints are built with a double o-ring seal, aswept elbow design that lowers pressureloss and stronger molding,proven to last 60% longerthan competitors’ in waterhammer testing.

The three-quarter-inchswing jointsalso offerleak-free reli-ability and operation at an economicalprice. For custom-length joints, a three-quarter-inch fittings kit is available for usewith contractor-supplied SCH40 pipe.

For more information on these newestproduct releases, turn to the Rain BirdAccessories Products and Pricing Catalog.

New Accessories. New Advantages.

The Cost ofKilowatts Today

How Much Does Electricity Cost for Your Controller?

Have you ever wondered how much it costsfor the electricity to operate an ESP con-troller? Several homeowner’s associationshave. It becomes an important questionparticularly when they have the controllerfor the community’s or development’s“common area” mounted on the property,drawing from their electrical service.

The formula below is useful for calculatingthe operating costs for any controller,whether it’s solid state or electromechani-cal. Simply find the data you need for yourparticular controller in the Reference section of Rain Bird’s Landscape IrrigationProducts Catalog. (You’ll find the most current version of this catalog online atwww.rainbird.com.)

Here, we’ll use an ESP-LX+ model as anexample. The ESP-LX+ uses approximately

0.13 amps of magnetization current to keepthe transformer operating at its peak.Remember that all amperage values listedhere are for 120 volts of AC current.

1 Volts x Amps = Power (watts)

In our case, 120 volts x 0.13 amps =15.6 watts2 Now, translate the watts into kilo-

watt-hours (1000-watt-hours equals 1 kilowatt-hour or kWh) and multiply thekWh by the cost of the power per kWh.

To find the current cost of power in yourarea, call your local power company or lookat your latest billing statement to determinethe cost of electricity in kilowatt hours.

FOR YOUR QUICK REFERENCE:ESP-4,6,8 Outdoor = 0.03 amps ESP-Si = 0.06 amps ESP-LX+ = 0.13 ampsESP-MC = 0.15 ampsAdd 0.12 amps during the timewhen a solenoid is energized.

To continue our example, we’ll estimate that the cost of local power is 10 cents per kilowatt hour.In this case, the power would cost $13.56 per year or less than 4 cents a day.

Example:

Total Power Cost = Watts x hours x (day, month, or year) x cost of electricity $ 0.XX1000 kWh

Yearly Power Cost = 15.6 watts x 24 hours/day x (365 days) x 10 cents = $13.661000 kWh

Daily Power Cost = 15.6 watts x 24 hours/day x (1 day) x 10 cents = $0.0371000 kWh

Costs: $13.56 per year or $0.037 per day to run the controller.

by Rod Waller

Try your hand at correctly answering the following questions about rotors. If you are one of the first 100 to submit all the rightanswers, you will receive a FREE Rain Bird hat.Choose one of the following answers for each.Circle your answers on the form below andsubmit it to Rain Bird by fax 520-434-6289 orby e-mail rwaller@rainbird.com. Please allow4-6 weeks for delivery of your hat.

1. An area with a long pipe run can require which rotor feature?

a. closed caseb. pressure-compensating designc. gear drived. both B and C

2. An area with a lot of foot traffic will usually require which type of rotor?

a. pop-upb. impactc. pressure-compensatingd. plastic

3. All Rain Bird rotors are lubricated by:a. oilb. airc. WD40d. water

4. Areas that are subject to high winds will typically need which rotor feature?

a.brass headb. internal ball drivec. check valved. low-angle nozzles or bodies

Name: __________________________________________

Company:_______________________________________

Address: ________________________________________

City: _______________State: _________ Zip: _________

Phone:__________________________________________

FAX: ____________________________________________

E-mail address: __________________________________

Put On Your Thinking Cap…What Do You Know

About Rotors?[ ]Keys To A Reliable Drip SystemPart I: Xerigation Control Zone Issues

With today’s increased consumer awarenessand attention to environmental factors andwater conservation, drip irrigation hasbecome one of the fastest growing segmentsof the irrigation industry. As drip systemsincrease in popularity, it has become important for professionals to have anunderstanding of good drip irrigationdesign practices, said Mike Baron, Directorof Rain Bird’s Landscape Drip Division. Adrip system delivers water slowly, at lowpressure, at or near the root zones oflandscape plant material. Baron said that,

because of this, it’s important to keep threekey issues in mind: filtration, pressure regulation and flow compatibility.

“Many problems in a drip system can betraced back to a design oversight having todo with one of these three control zoneissues,” said Baron.

1 Filtration

“If I’m using potable water, why do I have tofilter it?” Baron explains that the answer tothat question can best be seen by looking atan aerator screen such as that often foundin a kitchen sink faucet. Unscrew the faucettip, and you’ll always find small particles of

sand or rust caught in the aerator screen.Such particles can clog a low flow emitter,so you need to filter water to keep your dripsystem reliable and trouble-free.

2 Pressure Regulation

When using Rain Bird drip products, 50 psiis the magic number, the maximum pressurewe recommend for operating a drip systeminstalled with polyethylene drip tubing.“Exceed 50 psi,” says Baron, “and you arelikely to blow emitters right out of the tub-ing." Therefore, always use a pressure regu-lator if there’s any chance whatsoever thatyour drip system will see pressures in excessof 50 psi. Another reason this is a good prac-tice is that pressures in excess of 50 psi willcause most threaded, pressure-compensat-ing emitters to flow less than their rated flow.

3 Flow compatibility

Drip irrigation is known for its efficient useof water. That means you can water a givenarea using a much lower flow rate than if youwere watering with conventional sprays.That’s great for saving water and keepingwater off windows, but maybe not-so-greatfor your electric valve. All valves have a mini-mum flow specification that can be found inthe manufacturer’s catalog. If the flow in adrip zone falls below the valve’s minimumflow specification, you can run into prob-lems such as valve weepage or a valve thatjust won’t shut off, especially in drip retrofit situations.

To avoid this flow problem, use a Rain BirdXCZ-075 Control Zone. It puts a 200-meshfilter immediately upstream of the DV valvewhile ensuring a minimum flow specifica-tion of 0.2 gpm or 12 gph. The filter is pres-sure-rated to 150 psi, so it performs reliablyupstream of the valve, under constant pressure. Rain Bird also offers the 100-PEBvalve, which has a very low minimum flow specification of 0.25 gpm.

Like the valve, pressure regulators need to bematched to the flow rate. Remember tocheck the flow rate specification for yourpressure regulator. “Using a regulator ratedfor 2 to 22 gpm operation for a low volumesystem that flows only 75 gph (1.25 gpm)is the same as using no regulator at all,”

explained Baron. Remember, Rain Bird’s lowflow pressure regulators work from 0.1 to 5.0gpm (6 to 300 gph), and the medium flow regulators work from 2 to 22 gpm.

Don’t miss the second half of this two-partseries in the next issue. PART II— Why aren’tmy emitters flowing evenly or at all? How do you know a drip system is reallyworking since you can’t see the water?

Low VolumeIrrigation inHigh Demand