Conversing With Currents

By Dustin Stelzer | Feb 15, 2024
clamp-on ammeter
For most electricians, we’re big fish in a small pond, until one day we venture into new areas of the industry where we morph into small fish swimming in an ocean.




We don’t know what we don’t know, until we know it. For most electricians, we’re big fish in a small pond, until one day we venture into new areas of the industry where we morph into small fish swimming in an ocean. As a residential electrician building massive custom homes, my early days were rather simple. Drill holes, pull wire and try to make it pretty. I didn’t have much need to understand the complexities of harmonics, inductive reactance, capacitive coupling or, really, solving complex problems in general. Once I jumped into commercial and industrial service work though, I found my ocean.

As a service technician, you run into all sorts of problems. Almost nothing you touch from day to day is new—rather it’s opening up devices and equipment installed by other electricians long ago. 

Troubleshooting, by nature, means finding solutions. If the only tools you understand how to use are plug and voltage testers, you’re not going to be able to have a deep enough conversation with electricity to understand it fluently. Discovering new test equipment that can collect more data leads electricians to develop more vocabulary and a profound understanding of what circuits are doing. Once you speak the language, circuits begin to talk a lot more.

Every electrical system speaks to us. They’re trying to tell us when something is calling for power but isn’t operating correctly. They let us know when conductors are too hot, or when devices have bumps and bruises. They tell us there’s a nicked wire underground from the transformer feeding the service. They can tell us there’s a hot point in a panel where a termination is failing. 

They’re trying to talk to us, but without the proper test equipment, we can’t even hear what they’re saying. With a little bit of practice on some new equipment, we can open up a dialogue with an electrical system. Below is information on test equipment that can revolutionize the ability to solve problems in the field.

Clamp-on ammeter

The clamp-on ammeter stands out for its ability to measure current flow without needing to disrupt the circuit. It operates by encircling a conductor and listening for changing magnetic fields to determine the current passing through. This tool is particularly useful in situations where cutting off power is not feasible or could lead to further complications.

Electricians should be trained in the basic operation of the clamp-on ammeter and in understanding the affect of external magnetic fields and the importance of precise clamp positioning. Once it is understood how a multimeter can detect an expanding and collapsing magnetic field around a conductor, you can understand electromagnetism and induction in general. This will invariably lead to further understanding of many devices used in the field such as current transformers, inductors, contactors, relays and induction motors.

Underground line-locator

The underground line-locator is a critical tool for mapping and tracing the path of concealed cables, conduits and buried junction boxes. A line-locator works by attaching a signal transmitter to a conductor that leads underground and connecting the other side to an earth probe. 

The user wears a headset and listens for tones or dead quiet zones as they walk in the direction the conduit might go while waving the line-locator back and forth. The tester will tell you when you’re walking above the underground conductor, even if it is in a conduit buried under 3 feet of soil. These are accurate over incredible distances, and the skilled user can even find points underground where the signal begins spreading out—often signaling a burned-up conductor or buried junction box.

Electricians should be skilled in differentiating signal strengths and types of cables, as well as interpreting locator readings under various soil conditions. Understanding the intricacies of these readings is vital for accurate detection and mapping. This is an outstanding tool, especially if you do a lot of work on commercial parking lot poles or street lighting and just can’t find where that one wire goes.

Live circuit seeker

A live circuit seeker is indispensable for detecting the path conductors take through walls and ceilings, which allows the electrician to trace out potential buried junction boxes or conductor pathways when troubleshooting. During remodels, conductors often go from one portion of a home or business to another. The ability to hook on to a de-­energized or energized wire and trace it back to a breaker, or to find the pathway from room to room, can be massively beneficial.

Some seekers, such as low-voltage toners, can only be used on de-energized circuits, which can still be helpful. However, those that can be used on energized circuits can often solve problems that de-­energized versions may not. Understanding the different tones, signal strength and wiring methods takes practice, as users can think they’re tracing the correct wire just to find a bunch of neutrals connected and that their test is throwing them around the building giving bad readings.

Training must encompass device calibration for different materials, recognizing the limitations in depth detection and distinguishing between live wires and potential false positives.

Power quality meter

Sometimes problems appear to be ghosts, as not all electrical issues arise from obvious visible problems. When power factor problems or harmonic distortion begins affecting power systems, a simple voltage tester won’t tell you what’s wrong. 

Power quality meters assess the overall quality of supplied power and can record data over time. This includes analyzing voltage fluctuations, current irregularities, power factor inconsistencies, harmonics, transients, unbalance and other elements critical to power quality.

Electricians should be adept at interpreting complex data from these meters to diagnose issues such as voltage sags, swells, flickers and harmonic distortions. Understanding these parameters is crucial in identifying and rectifying power quality issues, which can have significant impacts on electrical systems and equipment. Though this type of test equipment can be incredibly costly, the amount of knowledge it enables an electrician to gain about electrical power, and what can cause problems in a system, makes them a wonderful teacher. They allow an electrical contractor to have an incredibly fluent conversation with an electrical system.

3-point fall of potential meter

This meter is employed for earth resistance testing, which is a key aspect of ensuring an effective grounding system. The 3-point fall of potential test is a renowned method for measuring earth resistance, which is crucial in mitigating electrical hazards. It enables an electrician to begin to understand soil resistivity and ensure the grounding system as a structure is doing its job.

Fall of potential meters use Ohm’s Law in the field and have a direct application of theory observable during a test. The tester monitors current, potential and resistance between three electrodes to determine a grounding electrode’s resistance to ground. A low impedance path to ground, typically below 25 ohms, is recommended on systems other than impedance-grounded.

There is also a 4-point fall of potential meter that offers more detailed information, especially about soil resistivity and its variation with depth. It is more complex and used in scenarios where detailed soil analysis is required rather than just resistance values.

Training on these testers should cover proper electrode placement and the impact of soil resistivity on readings. Electricians need to understand the procedures for conducting these tests to ensure the grounding system’s effectiveness and safety.


A megohmmeter, also known as an insulation tester, is designed to measure electrical insulation’s resistance. This testing is critical in preventing short circuits and leakage current, which are pivotal for maintaining the integrity and safety of electrical systems.

By passing a high-voltage current through conductors underground, an electrician can tell if they were damaged during installation. There may be small slices or gouges in conductor insulation that may not be making contact with a nearby conductor in dry conditions. However, when moisture and temperature change the characteristics of the environment, they can cause momentary short circuits. Megohmmeters are also used to test motor and transformer windings for insulation damage.

Electricians must understand the correct voltage levels required for testing different insulation types and be able to interpret resistance values accurately. Knowledge of safe testing procedures is also essential to prevent damage to the insulation and ensure operator safety.

Value of comprehensive training

Training on these specialty testers is about enriching electricians’ understanding of the complex electrical environments they encounter. This comprehensive knowledge enables them to make informed decisions, leading to more effective and efficient problem-solving.

Because electricity is not an observable phenomenon, less-experienced electricians may make assumptions about what is happening in an electrical system because they can’t see the full picture. Gaining access to better training with more advanced test equipment can bring them a more holistic understanding of electrical theory, giving them a broader range of solutions to employ when troubleshooting.

Not every company can afford to buy expensive test equipment, especially not for each technician. A common method of incorporating costly new equipment is to purchase and keep them locked up in the main office until needed. When they’re issued to a tech, ensure they sign the tester out and understand that their name is attached to it and they are solely responsible for it. It is recommended to do monthly training on test equipment so technicians continue to hone their application of test procedures.

In the dynamic field of electrical contracting, equipping yourself with knowledge and skills in specialty testing is not just an advantage; it’s a necessity. By investing in thorough training programs for these essential tools, electrical contractors can guarantee their operators’ safety, accuracy and efficiency. This depth of expertise is more than a competitive edge, it’s a commitment to excellence in the electrical contracting industry. Ensuring your techs can understand the language of electrical systems is crucial in their ability to be the best at what they do.


dustin stelzer / greenlee / fluke

About The Author

Stelzer is a master electrician from Austin, Texas. As the CEO of Electrician U, he’s dedicated to revolutionizing the trade industry through education, offering comprehensive courses, hands-on tutorials and insight. Under Dustin’s guidance, the platform aims to empower electricians with the knowledge and skills needed to excel in their craft. To learn more about Electrician U, visit





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