The 10 Best Clamp Meters

Editor's Notes

August 27, 2020:

During this busy round of updates, while the Etekcity MSR-C600 was replaced by the Mestek CM81 — another budget pick with superior features, though a heavier price tag; the Fluke 322 was replaced by the Fluke 325 — a step-up model that includes a built-in capacitance meter and a superior ohmmeter; and the UEi Test Instruments DL369 was replaced by the UEi Test Instruments DL429B — a step-up model that boasts app connectivity, as well as the ability to measure inrush current and temperature.

In order to make room for some gear offered by top brand names that weren't yet featured on our list, we also decided to do away with the Meterk MK06, Mastech MS2115A and Signstek UT210E. Our new additions were the Greenlee CM-1560 — which is backed by a limited lifetime warranty and boasts a large, two-inch clamp size; the Ideal Industries 61-775 — which features a 1,000-amp maximum current rating and comes with alligator-clamp test leads; and the BTMeter BT-570CAPP — a surprisingly affordable model that boasts a 49-foot Bluetooth range and app connectivity.

A few things to think about for this category:

Overvoltage Categories: This is a very important consideration. So, for your safety’s sake — pay attention. All electrical metering equipment is awarded an overvoltage-category score between one to four (sometimes simply referred to as a safety score). You’ll often see this denoted using the industry-accepted shorthand “CAT I, CAT II, CAT III or CAT IV.” While it would be easy for me to recommend that everybody purchase a CAT IV tester, and be ready for anything, the cost difference between a CAT I and CAT IV unit can be massive and, depending on your intentions for the meter, an inexpensive CAT II model might be just fine for you.

A basic breakdown of the categories is as follows:

CAT I: This designation is given to testers that are strictly intended for metering protected electronic equipment, and are not suitable for working on any electrical systems. CAT I options were not deemed acceptable for the purposes of these rankings.

CAT II: This designation is given to testers that are intended for metering unprotected electrical equipment and single-phase branch circuits (under certain circumstances). This is a limiting designation, and one that we tried to avoid for the purposes of these rankings.

CAT III: This is likely the most common designation for multimeters, and one that leaves them fairly well equipped. Devices of this category are serviceable for some electrical contractors, and are suitable for three-phase distribution work, as well as everything downstream from there.

CAT IV: This category’s on the top of the pile, ready to go up against just about anything you throw at it, including “point of origin” metering, which happens upstream of your main overcurrent protection for any electrical system.

At times, meters will be given ratings in two safety classes, with a maximum voltage denoted for each class (the higher the class, the lower the voltage). For example, the Fluke 325 is rated to work on CAT-III installations up to 600 volts, but is also suitable to take on CAT-IV installations, just as long as they don’t exceed 300 volts.

Connectivity: This is a capability that most won't have much practical use for, but for the scholarly electrician who’s working on complex systems or chasing harmonic distortions, modern models in this category have begun to incorporate the ability to connect to smartphone applications, to better track and distribute data. Notably, this can also come in handy for regular, run-of-the-mill electricians who want to meter equipment remotely while they go to hook up/disconnect a conductor elsewhere on a job site.

We recommend the UEi Test Instruments DL429B for professionals looking for a unit that offers app connectivity. But, if budget’s an issue for you, you might also be interested in checking out the BTMeter BT-570CAPP, which is considerably more affordable.

Bells and Whistles: Most the units we’ve ranked share a basic set of capabilities, but there are many models that have one or more standout features, as well. While the Greenlee CM-1560 is the only unit we ranked that’s backed by a limited lifetime warranty, the UEi Test Instruments DL429B is the only piece of equipment that is capable of taking differential temperature readings, courtesy of its pair of K-type thermocouples. The Fluke 325 is available with a certificate from the National Institute of Standards and Technology, and the Ideal Industries 61-775 features a secondary screen on the bottom of the unit.

A note on safety:

Electrical work is dangerous at the best times and, even in the context of some small around-the-house jobs, it can cause fires that lead to serious injuries or even death. If you aren’t a qualified professional, for the sake of your and your family’s safety (as well as local bylaws, in some cases) ensure that any work done on your home or business is completed by a reputable, licensed electrician.

June 08, 2019:

We realize that not everybody has the same needs from a clamp meter. For example, a professional electrician may need the ability to test more electrical aspects, as well as a unit with a CAT IV rating, whereas the average consumer may only need to check a few things, like circuit load or continuity, and will generally not be testing very high-voltage systems, so a model with a CAT III rating will usually suffice. If you work in the electric industry and need to troubleshoot a wide variety of issues, then you will be best served by the Klein Tools CL800, Fluke 323, and Amprobe AMP-210. All three of these models are CAT IV rated and offer true RMS measurements, which means they will be accurate when used on pure and distorted waves.

All of the rest of the models on our list are rated CAT III or less, so they don't have the capacity nor insulation to make them safe for use on high-voltage systems, though they should be more than suitable for home DIY use. However, this is why you'll notice a large price discrepancy between the aforementioned models and the rest of the units on the list. The outliers here are the GTC CM100, which is a high-quality unit specifically designed for low-current applications where you need to identify parasitic draws that may not register on other meters, and the Milwaukee 2235-20, which is definitely a well-built unit that will last through years of constant use, but we feel is overpriced based on its capabilities.

While on the topic of price, the UEi Test Instruments DL369 is worth mentioning for the value it provides. It is a streamlined device that is easy to operate and has a very solid build that can stand up to getting knocked around in a tool bag, yet costs less than most other commercial-quality options.