How to troubleshoot a 120v ground fault on a long wire run on your Golf Course

Scenario:

We were recently called by a Superintendent who had one of three 120 Volt power circuits/legs not working. The circuit supplied power to 10 satellites on the course. The problem surfaced right in the middle of the annual over seeding project. Of course the circuit went down on a Friday with temperatures in the mid 90’s. Just like main-line breaks, they never seem to occur on a Monday morning after it just rained. 

With most 120 volt field wiring problems, you are probably dealing with a ground fault if the circuit is tripping the breaker at the panel. This is due to the fact that electricity is constantly flowing to ground which is exceeding the amperage draw that the circuit can handle and subsequently, tripping the breaker. The breaker is just doing its’ job as it acts as a fail-safe tool and cuts off the power. This happens on all circuits so that electrical flow does not exceed design limitation which could result in a fire.

Troubleshooting such a long length of wire can be overwhelming if you do not have a solid plan on how to attack the problem and where to start.

Where to start:

The first thing to consider and ask is if there have been any recent projects which have involved digging. Have there been any mainline breaks, tree removal, new planters, any deep tine aerification?  Or have outside contractors been called in for any recent excavation projects?  Asking these upfront questions may give you some insight as to where the problem originated.

Locate an Irrigation Map

We recommend that you try to locate an As-Built map or the original irrigation design if available.  Accurate maps should show wire paths, junction boxes, satellite locations and other information which may assist you in the troubleshooting process. Having an accurate map will help you to visualize the project from a 30,000’ perspective so you can make heads or tails of the irrigation system layout.

Drive the Wire Path

Drive along the wire path and try to identify and locate any electrical junction boxes. Try to determine if there are junction boxes which tee off to feed individual satellites or if the boxes are located next to the satellites. It is important to get a lay of the wire path run before you start to whip out your fancy tools to trace wires. 

Pop a few junction box lids to visually see the condition of both the wires and wire connectors. If you notice that the junction boxes are filled with water, be cautious and ensure that the circuit is definitely OFF! Do not rely upon other personnel to turn off the circuit.  Check to make sure that the circuit is turned off yourself!  Reaching into an electrical box containing a LIVE /HOT circuit- filled with water, could result in a shocking experience causing severe injury or even death. 

Wire Splices

Visually look at the wire splices to see that they have been installed with the correct direct burial splice kits. If you see rust around the splice kits, or old corroded wires, this can give you a little insight that water may have seeped into the splices and has corroded the connections.

Feel the wire splice kits (With power off). If they are insulated in an industry approved, direct bury type of resin kit and they feel squishy or soft, then water may have entered the splice kit due to improper installation.  Check to see if the kits are cracked, are starting to break apart or if the split bolt connectors are sticking out of the splice kit. If you see any of these symptoms, you know the problem is right there. These are a couple of indicators that provide a clue as to where the problem resides. 

Cut your troubleshooting in half & (1/2) the wire run

The easiest way to start narrowing down where the problem may be is to half the wire run. Find an electrical junction box approximately 1/2 way along the wire path and cut off the connections on both the Power and Common wire. By doing this, you are eliminating and isolating half of the wire circuit. 

Go back to the circuit panel, and turn on the power again. If the circuit remains on without the circuit breaker tripping, then it is a safe bet that your problem is on the 2nd half of the wire run. If the breaker trips, then your problem is most likely on the first half of the wire run. There are no absolutes when it comes to electricity, but by using the “1/2 the circuit” method, you can save yourself a ton of time!

By doing the above, you have essentially narrowed your troubleshooting time in half.

The above step can be repeated by halving the half once again by repeating the above process and retesting the circuit. Once you have narrowed down the wire path, it is then time to begin wire tracking and ground fault locating to pinpoint the cause of your 120 Volt electrical problem.