Tools We Use: Clamp Ammeter – GreenBuildingAdvisor

Product Guide

A tool commonly found in an electrician’s toolbox can also be useful during energy audits and building investigations

I’m both an energy auditor (Building Analyst Technician and Building Analyst Professional) and a licensed journeyman electrician. That training provides a level of knowledge—and the confidence—to work safely around live electrical equipment. Electricity can be dangerous. If you’re not trained, don’t work on energized systems.

More than half of the energy audits I perform start with the same complaint: “Our electric bill is too high.” Sometimes the cause is building-related—a leaky enclosure or inefficient heating and cooling system. At other times it’s much simpler—a piece of equipment using more electricity than expected. Electric space heaters and dehumidifiers are a couple of common problem appliances I find.

Measuring electricity

There are several ways to measure electrical consumption. Plug-in meters, such as the Kill-A-Watt, work well for cord-and-plug appliances. Some newer load centers or service panels and smart breakers—such as systems from SPAN and Leviton Manufacturing—track usage in real time and record consumption over time. These systems are convenient during upgrades or new construction, but they’re not always compatible with older installations. Aftermarket monitors, such as Emporia Vue or Sense Energy Monitor, and smart plugs can fill that gap.

You can read more about these systems in this GBA article.

But when I need real-time data in the field, the tool I use most often is a clamp ammeter, also called a clamp meter or clamp-on meter. It allows me to measure current without disconnecting or cutting wires.

A clamp meter senses the magnetic field created by current flowing through a conductor and converts it into an amperage reading. Many modern models also measure voltage (AC/DC), resistance, frequency, and continuity.

The ammeter I use

My go-to meter is the Klein Tools CL700. It sells for about…