Lightning causes millions of dollars of damage to irrigation systems every year. The best solution to preventing damage is to have all electronic components and wiring properly grounded. This is typically overlooked on most irrigation designs because it is a rare event for most owners. Unfortunately, when is does happen the damage can be costly and time consuming.
This past Friday evening was a pre-4th of July show put on by Mother Nature. The lightning was intense and the number of strikes was numerous. I am sure the damage to several homes and property was severe. Lightning wreaks havoc with all irrigation systems because the control wiring is in the ground and in the yards. The control wiring (we call it field wiring) is what connects the controller (time clock) and the solenoid (zone) valves. The bigger the yard, the more solenoid valves buried in the yard and the more field wiring the more susceptible your irrigation system is to lightning. The control wiring is insulated copper wire and when lightning hits an object such as your home, a tree, a metal object it immediately wants to dissipate into the ground. If it finds that field wiring, it will then travel through the wire back to your controller to your solenoid valves and destroy them. Golf courses panic when we get these storms because they are typically big open spaces with miles of field wiring. I have seen the results of lightning striking the middle of a fairway and dissipating in all directions finding the field wiring and traveling back to the controllers and destroying them. Golf course superintendents go to extraordinary expense to protect these electronic components. The two most effective ways to protect any irrigation system is to ground the system and to install surge suppressors. There are several types of grounding methods including grounding rods, installing a copper earth plate, and connecting the controller to a ground. The goal of all grounding systems is to provide a safe pathway for electricity to travel back into the ground. Many of my clients have their controllers plugged into their house electrical outlet. This outlet, if your house is fairly new, is a GFI outlet and it will trip in a storm like Friday's. Reset the GFI by pressing in the reset button and hearing it click you know it reset properly. Plug a lamp into the outlet or some other simple device and make sure you have power at the outlet. Many times this is the simple fix. If you don't have power than check the circuit breaker on the panel to see if that also tripped. If you cannot get power than it is time to call a licensed electrician. If you have power at the outlet and you have no display on your controller or it will not operate than it may it may be time to call us for a service call. This past weekend we received a call from a client about zones staying on even though the controller was off and unplugged. In this case the lightning damaged the controller, the field wiring, and the solenoid. The solenoid blew apart from the voltage surge and the zone stayed on all weekend. Although you cannot protect any system from a direct lightning strike you can protect your irrigation system from an indirect flow of energy with proper grounding and surge protection. If you are in an area that is prone to lightning strike located near the water or high up on a hill then having grounding equipment and surge protection is vital to protect against costly repairs, replacements, and downtime. Grounding an irrigation system is relatively inexpensive compared to cost of repairs and it is not aesthetically objectionable in the landscape.
Facts about lightning and lightning strikes:
• About half of all strikes are 20,000 volts and 20,000 amps
• Some strikes can be greater than 100,00 volts
• Each flash contains as many as 45 strikes
• The average region in the U.S. can expect 2 to 30 strikes per year per square mile
• The U.S. receives 20 million lightning strikes per year
• A bolt of lightning can generate heat in excess of 50,000 degrees Fahrenheit
• Lightning converts nitrogen in the air into nitrous oxide which eventually converts into fertilizer for plants
• Over 1000 people struck in the USA each year.
If you would like to learn more about lightning then visit: National Geographic
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