S2, E33 - Tech Talk Tuesday: Grounding Testing

Video originally published September 2021.

Understanding Grounding Test Equipment

There are several types of equipment available for testing grounding systems, each with different capabilities and use cases.

The AEMC 4630 is a robust three-point and four-point grounding tester. This device is heavier and more expensive, but offers advanced testing capabilities including four-point ground testing. It features a green grounding connection lead, a red lead (also called the Z lead) which is the furthest stationary probe, and a blue lead which moves to various increments during testing. This meter was used in previous testing demonstrations and is available through Baseline with a part number, either through distributors using Baseline Bucks or by direct purchase.

The AEMC 6422 is a more compact alternative that only performs three-point grounding tests. It does not have four-point testing capability, which is a more advanced function. However, it is lighter, smaller, easier to use, and less expensive than the 4630 model. While this device does not currently have a Baseline part number, it may become the standard recommendation. Both meters can be purchased from electrical supply stores if not obtained through Baseline.

A clamp-on meter is another grounding measurement tool, but it serves a different purpose than the three-point testers. The clamp-on meter is used exclusively at the controller to measure the chassis ground. It works by clamping around the ground wire and provides an immediate reading. This device requires connection to the ground that is built into the electrical grid system (such as a house ground rod or other grounded electrical system) to function accurately. The clamp-on meter cannot be used to test field ground rods along the two-wire path—only the three-point testers can perform those measurements.

Target Resistance Values

There are two different target resistance values depending on what is being tested. For ground points along the two-wire path, the target is 25 ohms or less. For the controller chassis ground, the preferred target is 10 ohms or less.

While 25 ohms meets the specification for two-wire path grounding, aiming for 10 ohms or less is recommended whenever possible. Lower resistance at ground points results in less damage to the system during lightning events. When a ground point has high resistance (100 ohms, 200 ohms, or higher), it becomes difficult for surge energy to transfer off the wire path and into the earth where it belongs. Even if the installation meets specifications with an eight-foot rod properly connected to a surge arrester, high resistance means the energy will stay on the wire—which is a very easy path—and destroy device after device. Low resistance makes it much easier for surge energy to dissipate into the earth rather than damaging equipment.

In lightning-prone areas, particularly in the Southeast, shortening the distance between ground points provides additional protection. While the specification calls for grounding every 600 feet along the two-wire path, reducing this distance to every 300 feet means fewer devices will be located between ground points. If lightning strikes the system between ground points and destroys equipment, that equipment will be covered under warranty (if eligible), but it still represents system downtime. More frequent grounding reduces the number of components that could potentially be damaged in any single lightning event.

The 62 Percent Method Explained

The three-point grounding test uses what is called the 62 percent method. This test measures the ground resistance between the ground rod, the two-wire path, and the surrounding earth. The goal is to achieve the lowest resistance number possible.

The test involves taking three separate resistance measurements with the middle probe (blue lead) positioned at different distances from the ground rod being tested. The three measurement positions are at 72 percent, 62 percent, and 52 percent of the total test distance. The total test distance is calculated as 10 times the length of the grounding rod. For an eight-foot ground rod, the calculation is 8 feet × 10 = 80 feet total distance.

The three probe positions for an eight-foot rod would therefore be:

• 72% of 80 feet = 58 feet
• 62% of 80 feet = 50 feet (approximately)
• 52% of 80 feet = 42 feet

After taking all three measurements, the readings are averaged together to determine the actual ground resistance. The three readings should be within five percent of each other. If there is more than five percent variance between readings—for example, a 50 percent drop-off between measurements—the results should be discarded and the test should be repeated. Significant variance indicates a problem with probe placement, ground placement, or another technical issue with the test setup.

Preparing for the Test

Before beginning the test, gather all necessary equipment and prepare the reference document. A helpful resource available on the Baseline website is the document "Measuring Ground Resistance with the 62 Method." The URL for this document is printed on the sheet itself. Printing and laminating this document creates a durable field reference. This guide provides all the information needed to understand and perform the test, and can be reviewed in approximately 10 minutes. Adding personal notes or cheat sheet information to the laminated document, such as the distance calculations for common rod lengths, makes the testing process even more efficient.

The test requires three leads connected to the meter. The green lead connects to the ground rod being tested. The red lead connects to a probe that will be placed at the farthest distance (100 percent of the test distance) and remains stationary throughout all three measurements. The blue lead connects to a probe that will be moved to the three different measurement positions (72%, 62%, and 52% of the test distance).

To help remember which probe stays in place, label the red lead as "stationary." The red lead is attached to a spool of wire with a clip that connects to a ground probe. This probe will be driven into the soil at the full test distance and will not move during the test.

Performing the Three-Point Ground Test

1. Connect the green lead from the meter to the ground rod being tested.

2. Calculate the total test distance by multiplying the ground rod length by 10. For an eight-foot rod, the total distance is 80 feet.

3. Attach the red lead to a ground probe and run it out to the full test distance (80 feet for an eight-foot rod). Drive this probe into the soil. This probe will remain stationary for all three measurements.

4. Place the zero end of a tape measure at the ground rod and extend it out to the full test distance. Leave the tape measure in place throughout the test to mark measurement positions.

5. Calculate the first measurement position at 72 percent of the total distance. For an 80-foot test distance, this is 58 feet.

6. Attach the blue lead to a second ground probe and drive it into the soil at the 72 percent position (58 feet).

7. Turn on the meter by holding down the power button.

8. Press the Test button on the meter. The meter will display the resistance reading and hold it on the screen until cleared. Record this first reading.

9. Remove the blue lead probe from the 72 percent position and move it to the 62 percent position. For an 80-foot test distance, calculate 62 percent: 80 × 0.62 = 50 feet (approximately 48 feet for more precision).

10. Drive the blue lead probe into the soil at the 62 percent position.

11. Press Test again and record the second reading.

12. Remove the blue lead probe and move it to the 52 percent position. For an 80-foot test distance, calculate 52 percent: 80 × 0.52 = 42 feet (approximately).

13. Drive the blue lead probe into the soil at the 52 percent position.

14. Press Test again and record the third reading.

15. Calculate the average of the three readings. This average is the ground resistance value for the tested ground rod.

16. Compare the average resistance to the target values: 25 ohms or less for two-wire path grounds, or 10 ohms or less for controller grounds. If the resistance exceeds these targets, the ground installation has failed and must be improved.

Factors Affecting Ground Resistance

Several factors influence the resistance between a ground rod and the surrounding soil. Understanding these factors helps explain test results and guides decisions about how to improve poor grounding.

Soil type has a significant impact on ground resistance. Clay soil has fine particles that provide many contact points with the ground rod or probe, resulting in lower resistance. However, clay soil can be compacted and difficult to penetrate when driving rods or probes. Sandy soil penetrates easily, making rod installation simple, but the larger particle size means fewer contact points with the ground rod, resulting in higher resistance. Sandy soils often contain silica, which is what glass is made from. Since glass is an excellent insulator, sandy soils with high silica content present particular challenges for achieving low resistance. The combination of sandy soil, high silica content, and lightning-prone areas creates a very difficult situation for grounding systems.

Moisture content affects ground resistance significantly. Dry soil has much higher resistance than moist soil. For new installations, drive the ground rod early in the construction process and allow it to settle. Driving a rod creates air pockets around it, and air is an insulator that increases resistance. Allowing time for the soil to settle and compact around the rod reduces these air pockets. If possible, install ground rods in irrigated areas and begin irrigating the soil around them. If a ground rod must be installed in a non-irrigated area with very dry soil, consider placing one spray head or rotor near the ground rod to keep the area consistently moist, which will help maintain lower resistance.

Moisture also affects the ability to drive test probes into the soil. Dry, compacted soil is difficult to penetrate and hammering probes into it can damage the equipment. It also creates air pockets around the probe that affect test accuracy. Moist soil allows easier probe insertion with less impact.

Shallow groundwater can help achieve lower ground resistance because the ground rod or plate makes contact with the water table. However, attempting to reach groundwater by driving extremely long rods (such as pounding multiple rods on top of each other to reach a water table at 40 feet depth) creates problems. Excessively long ground rods expand the sphere of influence, which can cause the ground rod to interfere with the controller or two-wire path. Reaching groundwater is beneficial, but not at the expense of creating a sphere of influence problem.

Understanding Sphere of Influence

The sphere of influence is the area around a ground rod where it radiates energy back into the surrounding space. The sphere of influence is directly related to the length of the ground rod or plate.

For a ground rod, the sphere of influence extends in all directions equal to the length of the rod. An eight-foot ground rod has an eight-foot sphere of influence in every direction: eight feet to each side (creating a 16-foot diameter) and eight feet below the rod. Visualize this as a sphere with the rod at its center. To prevent the ground rod from transferring energy back to the two-wire path, the rod must be installed at least one rod-length away from the wire path. An eight-foot rod must be at least eight feet away from the two-wire path—eight feet and one inch is acceptable.

If a ground rod is extended to increase its effectiveness, the sphere of influence increases proportionally. A 16-foot rod (created by connecting two eight-foot rods) has a 16-foot sphere of influence. If this extended rod is only eight feet from the two-wire path, it will be within the sphere of influence and can transfer energy back to the wire path, creating problems rather than solving them.

Ground plates have a much smaller sphere of influence than rods. The sphere of influence for a plate is equal to its diagonal measurement from corner to corner. A 36-inch square plate has a sphere of influence of slightly less than 37 inches (the diagonal distance across the plate). This means plates can be installed much closer to the two-wire path than rods while still remaining outside the sphere of influence. A 36-inch or 48-inch plate can be positioned much nearer to the wire path than an eight-foot rod, making plates useful in situations where space is limited.

Ground Rods vs. Ground Plates

Both ground rods and ground plates are used for two-wire path grounding, and each has advantages in different situations.

Ground rods are more commonly used because they are less expensive and easier to install. An eight-foot rod can be driven directly into the soil with minimal effort in appropriate soil conditions. Rods are the preferred choice in areas with deep, clay-based soils without significant rock content. However, rods have a larger sphere of influence (equal to their full length) and must be installed farther from the two-wire path. In rocky soil conditions, driving a rod becomes difficult or impossible. If a rod encounters a rock at two feet or six feet depth, there is a temptation to cut the rod shorter, but this creates a problem: the installation may appear to have an eight-foot rod when it actually only has a four-foot rod in the ground, resulting in very high resistance and a failed ground.

Ground plates are more expensive than rods but offer several advantages. Plates have much more copper surface area in contact with the soil compared to rods. This increased contact area is particularly beneficial in soils that have difficulty achieving low resistance, such as sandy or gravelly soils with large particle sizes. In some challenging soil conditions, ground plates may be the only option for achieving acceptable resistance values.

Plates are commonly used when there is insufficient space to install a rod at the required distance from the two-wire path. For example, at an island or median strip where space is limited, a four-foot ground plate can be installed closer to the wire path than an eight-foot rod while still remaining outside the sphere of influence.

In rocky soil conditions, plates are often the better choice. In areas where mini excavators are used for trenching main lines (rather than chain trenchers), installing a plate is straightforward: dig the trench with a 12-inch or 18-inch bucket, and when ready to install the ground, use the excavator bucket to widen the trench, set the plate with grounding enhancement material, and backfill. No additional digging or specialized equipment is required.

Some specifiers require both rods and plates to be installed together for maximum grounding effectiveness.

Grounding Enhancement Materials

Grounding enhancement materials are products designed to improve the contact between ground rods or plates and the surrounding soil, thereby reducing resistance. These materials are particularly useful in challenging soil conditions.

Different products are formulated for different soil types. Powerset is designed for use in sandy soils, while Powerfill is formulated for clay-type soils. The different formulations account for the different characteristics of each soil type. Always consult the manufacturer's specifications to select the appropriate product for the specific soil conditions at the site.

Some grounding enhancement products include moisture-attracting agents. These products, which are different from the base grounding compounds, attract and hold moisture in the soil around the ground rod or plate. They function similarly to moisture-holding products used in turf management, though they are not typically gel-based (as gels can expand and cause problems). These moisture-retention additives help maintain consistent moisture levels around the grounding system, which helps maintain lower resistance over time. These products are particularly common in Florida and other areas where maintaining soil moisture around ground points is challenging.

Improving Failed Ground Resistance

When a ground resistance test shows values above the target (25 ohms for two-wire path grounds or 10 ohms for controller grounds), several methods can improve the resistance.

Install additional ground rods or plates and connect them together. Multiple ground points connected in parallel reduce the overall system resistance. Testing can then be performed on the entire grid of ground points as a system rather than individual points. This is the approach used in electrical substations and other installations that require very low ground resistance.

Ensure adequate moisture content around the ground rod or plate. If the ground was installed in dry soil, begin irrigating the area to increase soil moisture. For grounds in non-irrigated areas, consider adding irrigation coverage specifically to maintain moisture around the ground point.

Verify the actual rod length in the ground. If a rod was cut short due to encountering rock or other obstacles, it will have much higher resistance than expected. The rod must be the full specified length (typically eight feet) to achieve proper grounding.

Consider switching from rods to plates in difficult soil conditions. The increased copper surface area of plates provides better contact with the soil and can achieve lower resistance in sandy, gravelly, or rocky soils where rods perform poorly.

Use grounding enhancement materials appropriate for the soil type. These materials improve the contact between the ground point and the soil, reducing resistance.

Add moisture-retention products to the grounding enhancement material in areas where maintaining soil moisture is difficult.

Testing Frequency and Maintenance

Ground resistance testing is required one time for warranty eligibility, but periodic testing is recommended to ensure the grounding system continues to perform properly. Annual testing is a good practice, as soil conditions, moisture levels, and other factors can change over time and affect ground resistance.

For routine checks at controllers, a clamp-on meter provides a quick way to verify the chassis ground without performing a full three-point test. This is particularly useful when troubleshooting a site or verifying whether a site has applied for the 10-year warranty. Simply clamp the meter around the ground wire at the controller to get an immediate resistance reading.

Equipment Resources

Three-point ground testing equipment represents a significant investment. While the smaller AEMC 6422 meter is less expensive than the larger 4630 model, it is still a substantial cost. Contractors and end users may not need to own this equipment, as distributors typically have access to these meters or can obtain them. Distributors are well-positioned to offer ground resistance testing as a service to their customers.

For distributors, investing in a three-point ground tester—particularly the more compact 6422 or 6424 model—provides a valuable service offering. These meters come with the necessary reels of wire and probes, and are easier to use than larger models. Providing professional ground testing services helps ensure customer installations meet specifications and perform reliably.

The key takeaway for all parties is that proper grounding requires more than simply meeting the specification of installing an eight-foot rod or three-foot plate. True grounding effectiveness is measured by achieving low resistance at those ground points, which requires proper testing with appropriate equipment.

S1, E13 -Tech Talk Tuesday: 3 Point Grounding Testing

Video originally published September 2021.

Why Proper Grounding Matters

Proper grounding on two-wire control systems is critical for protecting equipment and preventing catastrophic damage. When an irrigation controller's outside wire is struck by lightning, the surge can carry up to 30,000 volts directly into the building. Without proper grounding, this surge has nowhere to dissipate safely. In documented cases, ungrounded controllers have been blown off walls mid-flight, leaving scorch marks and creating serious fire hazards. The purpose of grounding is to provide a low-resistance path for electrical surges to jump off the wire path and return safely into the ground, minimizing damage to controllers, decoders, and other connected devices.

Understanding the AEMC 4630 Ground Testing Kit

The AEMC 4630 tester is the recommended device for testing grounding locations on two-wire systems. The complete kit includes several key components that work together to measure ground resistance accurately.

The yellow tester unit features a large yellow test button on the lower right corner and four color-coded terminals: red, blue, black (which is not used in this testing procedure), and green. Each terminal connects to a corresponding lead wire. The red terminal connects to a red spool of wire, the blue terminal connects to a blue spool of wire, and the green terminal connects to a green lead that clips directly onto the existing ground rod being tested.

The kit also includes probes that are inserted into the ground at specific distances to measure resistance between the installed ground point and various points along the soil. A tape measure is included because measurements must be taken at precise distances based on the length of the ground rod. The tester contains a rechargeable battery, making it completely portable for field use. While the kit comes with a nylon carrying case, many technicians prefer to store it in a more protective hard case for transport.

Ground Rod Placement Requirements

Before testing, it's important to understand where ground rods must be installed along the two-wire path. The specification requires a grounding point every 600 feet along the two-wire path, as well as on spurs, terminations, and within the first 25 feet of the controller. Each of these ground points must be tested individually using the three-point ground testing method.

In high lightning-prone areas, particularly in the southeastern United States, it is strongly recommended to install ground points every 300 feet rather than every 600 feet. While 600-foot spacing still meets specification, closer spacing at 300 feet significantly reduces the likelihood of system damage by providing more opportunities for surges to dissipate into the ground before reaching and destroying decoders and other connected devices.

Calculating Test Distances

The three-point ground testing method requires taking measurements at specific distances from the ground rod being tested. All distances are calculated based on the length of the ground rod itself.

First, determine the total test distance by multiplying the ground rod length by 10. For an 8-foot ground rod, the total distance is 80 feet. For a 10-foot ground rod, the total distance is 100 feet. This is where the farthest probe (the red or "Z" lead) will be placed.

Three resistance readings are then taken with the blue probe (the "Y" lead) at three different percentages of this total distance: 72%, 62%, and 52%. For an 8-foot rod with an 80-foot total distance, these positions are at 57.6 feet, 49.6 feet, and 41.6 feet respectively.

Setting Up the Test Equipment

1. Disconnect the ground rod from the controller or two-wire path. The test must measure only the resistance of the ground rod itself in the soil, not the resistance of the entire connected system.

2. Connect the green lead from the tester directly to the ground rod. Clip the lead directly onto the rod itself rather than onto any clamp that may be attached to the rod. Testing directly on the rod ensures you're not including the resistance of a potentially poor clamp connection in your measurement. If the rod has a pre-attached lead or cadweld connection that cannot be removed, you may need to test on that lead, but direct rod connection is always preferred.

3. Lay out the tape measure from the ground rod to the full test distance (10 times the rod length). Place the zero end of the tape measure at the ground rod location so you don't have to remeasure for each reading.

4. Take the red lead with its attached probe and walk out to the full distance (100% of the calculated distance). Insert the probe firmly into the ground and clip the red alligator clip onto it. This red lead is called the "Z" lead and remains at this position throughout all three readings.

5. Take the blue lead with its probe and walk out to 72% of the total distance. Insert this probe into the ground and clip the blue alligator clip onto it. This blue lead is called the "Y" lead and will be moved for each of the three readings.

Taking the First Reading (72% Distance)

1. With the green lead connected to the ground rod, the red probe at 100% distance, and the blue probe at 72% distance, you now have three points connected for three-point ground testing.

2. Press the large yellow test button on the tester unit.

3. Allow the reading to stabilize. The display will show the resistance measurement in ohms.

4. Record this first reading. In the demonstration, the first reading at 72% distance was 51.1 ohms.

Taking the Second Reading (62% Distance)

1. Remove the blue probe from its current position and move it closer to the ground rod, to 62% of the total distance.

2. Insert the probe firmly into the ground and reconnect the blue lead.

3. Press the yellow test button again and allow the reading to stabilize.

4. Record this second reading. In the demonstration, the second reading at 62% distance was 50.4 ohms.

Taking the Third Reading (52% Distance)

1. Remove the blue probe again and move it to the final position at 52% of the total distance.

2. Insert the probe into the ground and reconnect the blue lead.

3. Press the yellow test button and allow the reading to stabilize.

4. Record this third reading. In the demonstration, the third reading at 52% distance was 50.0 ohms.

Calculating and Interpreting Results

Once all three readings are recorded, calculate the average resistance by adding the three readings together and dividing by three. In the demonstration example: (51.1 + 50.4 + 50.0) ÷ 3 = 50.5 ohms.

Before accepting this average as valid, verify that the three readings are within 3-5% of each other. Significant variation between readings indicates a problem with soil conditions or the testing setup, and the results should not be trusted. In the demonstration, the readings varied by less than 3%, which is acceptable.

The maximum acceptable ground resistance is 25 ohms to meet basic specifications. However, the preferred target is 10 ohms or less. When resistance is below 10 ohms, it is much easier for electrical surges to jump off the wire path, resulting in significantly less damage to the system. The demonstration result of 50.5 ohms fails both the 25-ohm requirement and the 10-ohm preferred target.

In real-world testing, if the first reading is significantly above 25 ohms (such as the 51.1 ohms in the demonstration), you can immediately determine that the ground point will fail without taking the remaining readings. At that point, efforts should focus on improving the grounding conditions rather than completing the test.

Improving Ground Resistance: Moisture Content

Soil moisture content has a dramatic impact on ground resistance. Dry soil creates high resistance, while moist soil significantly reduces resistance and improves grounding performance.

In the demonstration, the ground rod was installed in an un-irrigated portion of the yard. When first tested a week earlier in completely dry conditions, the resistance measured over 200 ohms, and the probe had to be hammered into the hard ground. After watering the area throughout the week, the resistance dropped to approximately 50 ohms. With additional watering and time for moisture to spread through the clay soil, the resistance would likely drop to 10-20 ohms.

The key recommendation is to install ground rods in irrigated areas whenever possible. Placing ground rods in turf areas that receive regular irrigation naturally maintains the moisture content needed for low resistance. If a ground rod must be installed in a non-irrigated area, consider adding a rotor or spray head specifically to keep that area moist year-round.

When testing ground resistance on day one of a new installation before irrigation has been established and plant material is growing, it's advisable to wait and retest after the irrigation system has been operating and moisture content has stabilized. Initial high readings in dry soil may improve dramatically once the area is regularly irrigated.

Improving Ground Resistance: Rod Length

The length of the ground rod directly affects the amount of contact surface area between the rod and the surrounding soil. More contact area means lower resistance.

Always verify the actual installed length of the ground rod before testing. If you assume an 8-foot rod and calculate test distances accordingly, but the rod was actually cut short to 4 feet because the installer hit a rock, you have only half the expected contact area with the soil. This will result in failed resistance readings.

In the demonstration, short travel rods (cut into sections for portability in a travel kit) were used instead of a full 8-foot rod. Two 3-foot rods were driven and connected together with number 6 wire, but this still did not provide adequate grounding. A full-length 8-foot rod driven to its complete depth would have provided significantly better results.

If a ground rod cannot be driven to its full depth due to rock or other obstructions, the grounding point will likely fail testing and alternative solutions must be implemented.

Improving Ground Resistance: Soil Type

Different soil types provide vastly different levels of contact with the ground rod, which directly affects resistance.

Fine-textured soils such as silt and clay provide excellent contact with the rod along its entire surface, resulting in lower resistance. These soil types are ideal for standard ground rod installations.

Coarse soils such as sand, gravel, and rocky soils only make contact with the rod at scattered points along its length, creating much higher resistance. In these challenging soil conditions, a standard ground rod may never achieve acceptable resistance levels.

For sandy or rocky soils, alternative grounding methods may be necessary. Ground plates can provide more surface area contact than rods. Setting multiple ground points and connecting them together can also reduce overall resistance. In some cases, specialized grounding materials may need to be installed around the ground point to improve conductivity.

Testing Multiple Ground Points Along the Wire Path

Each ground point along the two-wire path must be tested individually. For a system with ground points every 600 feet, this means disconnecting the ground wire from the two-wire path at each location, testing that specific rod with the ground kit, recording the results, and then moving the entire kit to the next ground point 600 feet away.

While the testing procedure itself is not difficult once you've performed it one time, the time-consuming aspect is physically moving the equipment every 600 feet along what may be a 3,000-foot or longer wire path. Each ground point must be tested to verify that the entire system meets specifications.

If you discover a location where a ground rod is missing entirely or was never installed, that point automatically fails and cannot be tested. The system is not eligible for extended warranty coverage until that ground point is properly installed and tested.

Controller Ground Testing vs. Wire Path Ground Testing

Testing the controller ground requires different equipment than testing ground points along the two-wire path. Controller ground testing uses a clamp-on meter that looks similar to an amp clamp. This grounding clamp meter is used when testing something connected to the electrical grid, measuring the ground point in relation to the outside power system.

The AEMC 4630 three-point ground tester described in this guide is specifically for testing ground points along the two-wire path. If you have a conventional hardwired system with no two-wire path, you only need the clamp-on meter for controller ground testing. If you're using a two-wire system, you need both the clamp-on meter for the controller and the three-point ground tester for the wire path ground points.

Extended Warranty Requirements and Documentation

Baseline offers a 10-year extended warranty that covers the controller and all two-wire devices connected to the wire path. To qualify for this warranty, ground resistance testing must be completed and documented, with all ground points measuring 25 ohms or less. The preferred target is 10 ohms or less for optimal surge protection.

The 10-year warranty application form is available on the Baseline website under the Support tab, then Warranty Information. The form can be completed online, with all required fields filled in for the specific project. A PDF version is also available that can be used as a checklist in the office or field before entering the information online.

Baseline keeps these warranty applications on file internally in the support department. When a warranty issue arises on a project, the support team can verify that the project has the extended warranty, pull the file to verify the ground resistance testing measurements and results, and process the RMA if necessary.

Bidding and Scope of Work Considerations

While the three-point ground testing process is not technically difficult, it does require significant time, especially on projects with extensive two-wire paths. Contractors must account for this time when bidding projects where the extended warranty will be applied.

If the project specifications require the 10-year warranty, the contractor should ensure that the time needed to perform ground resistance testing at every required location is included in the bid and scope of work. This ensures the contractor is properly compensated for the testing time.

Testing may also reveal deficiencies that were not properly completed during installation, such as missing ground rods, improperly installed rods, or ground points that fail resistance testing and require remediation. The time and materials to correct these issues should also be considered.

If the extended warranty is not part of the base bid, contractors can include it as an add-alternate with a price, allowing the owner to choose whether to apply for the extended warranty and pay for the associated testing and verification work.

Acquiring Ground Testing Equipment

The AEMC 4630 ground testing kit can be acquired through several channels. Baseline has a part number for this specific model, and it can be ordered through your Baseline distributor. Distributors can order the kit using Baseline Bucks as an incentive. The kit can also be purchased directly from AEMC or through electrical supply houses.

Baseline does not profit from the sale of these testing kits; the goal is simply to ensure that proper ground testing is performed correctly to protect systems and qualify for warranty coverage.