Electrical Test Equipment Every Electrician Should Know
It’s an electricians job to be able to identify what’s going on in an electrical circuit, and sometimes this can be a difficult task. Having a firm knowledge of how to use various pieces of electrical test equipment can be the difference in solving a problem and making a guess. In this episode, I cover all of the pieces of test equipment I believe an electrician should know how to use.
#1 Basic Jaw-Type Multimeter/Tester
This is a pretty obvious piece of equipment for an electrician to have, but you’d be surprised at how many electricians and apprentices out there don’t know how to use one. Well, let’s dive in!
For starters this is not “technically” a multi-meter. Fluke calls it a tester, but most of us in the field still call it a multi-meter, so for the sake of this article I’m going to continue calling it a multi-meter. It has multiple functions, which is why we call it a “multi-meter.” It can read voltage (difference of potential), amperage (current flowing in a conductor), resistance (opposition to current flow in a conductor), and continuity (whether or not you have a complete loop.
Most of the time, this is all an electrician will need to know. This Fluke T5-600 fits in your back pocket, has detachable leads that can be snapped into the tool, or used hands-free, and a backlit LED display. This model is one of the most used testers on the market, and because of its rigidity and reliability will continue to be so for quite some time.
#2 Clamp-on Ammeter
The clamp-on ammeter is similar to a standard tester or multimeter with the addition of a clamp/jaw that reads amperage on large diameter conductors. What the clamp provides is the ability to measure larger size wires for use on feeders and service-entrance conductors. In addition to measuring amperage, this tester also allows you to read voltage, resistance, continuity, and capacitance. This specific model (Fluke CL323) does not allow you to snap the leads to the tool so it can be a bit cumbersome to use when testing voltage – unless you have something nearby that you can clamp on to, allowing the tester to hang in front of you while you use the leads with both hands.
#3 Pocket Voltage Tester
The pocket tester is for quick and convenient AC/DC voltage testing. It’s not a high-dollar, 100-feature tester but it does allow you to test if power is present in a circuit. It fits easily in your pocket, so I personally keep one of these on me everywhere I go. You never know when you’ll need to use it, but when you don’t have all of the rest of your tools on you – carrying this around will give you a little bit of an edge, and possibly save you a trip to the truck.
This tester can test ranges from 0 – 240v AC and 0 – 17v DC making it extremely versatile as most electricians work in both of these ranges, most often. Do not try using this meter on 480-volt systems as it is only rated for up to 240v max.
#4 Tick Tracer
Taking a walk down the average Facebook Group or Electrical Forum, you’ll come to know that the use of a tick-tracer is a rather contentious issue. And for good reason. A lot of people have gotten hurt thinking that the audible beep this tester gives off, should be trusted for accuracy. These tools are not very accurate and have a definite purpose, but a very limited one.
First things first – DO NOT USE THIS AS A REPLACEMENT FOR A MULTIMETER. Always double check with a multimeter before touching a wire. What the tick tracer is used for is testing for the presence of power. If you’re unsure whether or not there is power on a conductor or not, you can use this tick-tracer to tell you that. It doesn’t tell you anything beyond that. Some of these are auto-ranging so they’ll tell you if you have low voltage or line voltage present – but again….ALWAYS DOUBLE CHECK WITH A MULTIMETER BEFORE STICKING YOUR HANDS ON A WIRE! his tool is battery powered so make sure you always have an extra set just in case yours are low. If you are going to use this tool, know that it uses capacitive coupling so it’s not sensing true “power” meaning it’s possible for you to get readings that make no sense. Not the most reliable tool in your belt however it is good for quick diagnosis when checked afterward with an actual multi-meter.
#5 GFCI Plug Tester
Every electrician uses a plug tester, or at least they should. You could, of course, use a multimeter to get readings on an outlet, however when you need to walk away from the receptacle and visually see whether or not the plug is on or off, having something that sticks into the receptacle is extremely valuable. A plug tester will have 3 LED lights on it, that light up in different ways depending on how the receptacle is wired. It will tell you if you crossed your wires up, wired things backwards, or didn’t hook up a wire. It can also be used similar to a tick-tracer to identify if a circuit is on or off as well.
I recommend getting a gfci-testing version as it allows you to manually test whether or not a GFCI device is good or bad. This feature also comes in handy when you’re unsure whether or not a receptacle is on a GFCI circuit or not. Many inspectors use these to test circuits for GFCI protection, so being ahead of the game is a good idea.
#6 Low Voltage Toner
This tester is a tone generator, and when powered up sends a signal through two conductors allowing you to wave a “wand” (receiver) across a wall to find the path of a conductor. Once it senses the wire it will let out a loud tone so you can locate exactly where the wire was run. You do need to be sure to turn the circuit off when using this toner, as it is a low-voltage toner. Running 120v line-voltage through it will instantly fry it. Sometimes this can be an unreliable tool, depending on how a circuit was wired. For instance, many homes are wired with all neutrals (grounded conductors) wired together all over the place. This will lead the tone to be unreliable and appear in many different spots rather than just at the beginning and end of the circuit. Just be aware of this when doing remodels in 1960s homes! All that said, in a pinch, this little tool can be a job site hero when understood and used correctly.
#7 Circuit Tracer
Circuit tracers are outstanding tools for every electrician to have available to them. I find that I use mine most when in commercial environments where you have panels all over the place, or have unlabeled (or incorrectly labeled) breakers – however, they can be used in any environment.
A circuit tracer will send out a signal (much like a low-volt toner) from the transmitter, and you wave a wand (receiver) in front of a panel to identify which panel the circuit comes from. It will also tell you exactly which breaker the conductor is coming from. Probably the most useful part of this tool is that the signal it sends does not interfere with the power on the circuit when the breaker is on. This means you can trace out a live circuit! When you’re in large businesses that have circuits that absolutely cannot be shut off, you need a tool that can find a breaker and know with precision, which circuit you’re working on. The worst thing in the world is accidentally shutting off the wrong breaker and killing an entire line of cash registers during a rush at a grocery store. Save yourself the trouble and embarrassment and get a circuit tracer. They are game changers.
#8 Megger (Megohmmeter)
Most standard multi-meters only test resistances of up to 1,000 ohms. While that is a large resistance, it doesn’t help you to identify whether or not insulation on a conductor has been compromised. This is something not a lot of people test for as many electricians do not have the right equipment. What you need to know, is the Megger. Megger is a brand that makes Megohmmeters, but a lot of other brands do too. We just call them a Megger out in the field, regardless of the brand.
The megohmmeter is for you to test for high resistances such as those found in insulators – which can be hundreds of thousands, to even millions, of ohms. This becomes useful when testing motor windings or underground service entrance conductors and feeders. Rather than just taking a guess and saying a device is bad, pull out your Megger and see what’s actually going on. Many megohmeters still read all the same things a regular multimeter does (amperage, voltage, resistance, and continuity). It tests up to 1000v, tests leakage currents, it has a hazardous voltage alert, and it’s got a magnetic back for hands free resistance testing. Basically if you’re working on a large job in which you need to find out the high resistance and also need all the perks of a multimeter in one tool, the megger is your guy.
Word of caution – this tool should only be used by an experienced electrician that knows how to use it. It can generate up to 1,000 volts at the leads with some models even going up to 5,000 volts. You can get hurt using a Megger. Consider yourself warned!
#9 Line Locator
The line-locator is one of my favorite pieces of test equipment to use. Really because it’s saved me time and time again when I otherwise would have sat there scratching my head in the middle of a parking lot somewhere. It’s essentially an underground toner. It sends a high-voltage signal on a single conductor over an incredibly far distance – up to 4,000ft! One probe references ground and the other is hooked up to a conductor. Some sets have headphones, though you’re not required to use them, and rather than a “tone”, you’re listening for silence or “null” between two tones. When you’re not using headphones the line locator will emit an audible tone when you’re above the path of the wire. You typically use these outdoors or in slabs to find the path of a conduit or conductor. Line locators also help find breaks or shorts in wire underground as well. They can penetrate the ground up to 7ft deep, making them one of the most bad-ass toner-style testers out there. And the most accurate.
#10 Digital True RMS Multi-meter
When saying the word “Multi-meter,” this is what you’re talking about. The Fluke 117 is just an entry-level model, but there are tons of brands and models that do incredible things these days. Most models will, at a minimum, read voltage AC, voltage DC, amperage AC, amperage DC, resistance from 0-1000ohms, continuity, and capacitance. Some read the temperature, some have graphing and recording functions, and some have even more features than are worth talking about – and they’re extremely expensive to boot.
I personally like models that come with a magnetic strap so you can stick it to a panel or enclosure while using it. I also like when these models also include snap-in slots for the test leads, so you can use the tool like a standard tester. This is a very powerful tool to have in your arsenal, regardless what brand or model you go with. The more functions on a multi-meter you know how to use, the better electrician you’ll become.
#11 Coax Continuity Tester / Ethernet Wiremapper Tester
This is a 2-in-1 that will really help out with your data jobs. There is both an ethernet and coax continuity tester in this little guy. The coax continuity tester portion tests for continuity of a coaxial wire to see if a good termination has been made on both ends of a cable. The other part is an ethernet tester that will test cat3 to cat 6 patch cables for terminating RJ45’s on data runs. This tool will detect reversals, mis-wires, shorts, shield continuity, and opens. It also has easy to read interface with LED lights that show you exactly how you’ve terminated your cables, and whether or not you need to address any issues.
On the front of the tester is a diagram that shows both “A” and “B” configurations for wiring cat 5 and cat 6 connections. This is a huge help so you don’t have to memorize the wire-order, or look it up on google for reference.
This is a long, and very comprehensive list, of electrical test equipment that I think every electrician should know how to use. That’s not to say that you need to have every one of these on your truck or van, but at least having the know-how on HOW to use them will set you apart as an electrician who knows how to be a detective, rather than just a laborer who makes guesses.