Isolating the measuring instrument from other circuits and earth is a simple task when using an analog meter. Most analog meters have two terminals to connect the input and no other circuit connections. The plastic case provides an insulation barrier to the metal panel or cabinet, which is tied to earth for safety. (more…)

As the cost of energy escalates, an important issue for many businesses is how to monitor power consumption – for a device, a process, a department or an entire facility. This is typically done with a power meter or energy meter. Before we explore various instruments available for this, a quick review of basic power system parameters is warranted. (more…)

An instrumentation switch (or instrument switch) is a special-purpose switch used in conjunction with an electrical meter in a control panel. It allows a single meter to read multiple circuits. The most common application is monitoring three-phase ac power systems. The meter is switched into the circuit to make a measurement. (more…)

The Simpson 260 has been an industry-standard multimeter for over 70 years. It is now available in 13 versions including industrial, ruggedized, safety rated, and high accuracy models. Why is this analog product still used, despite the abundance of digital multimeters? More generally, what advantages does an analog meter have compared to its digital counterpart? (more…)

Last month’s posting covered the popular methods for sensing AC current (shunt, current transformer, Hall sensor, Rogowski coil). Here we will review some of the instruments available for fixed, portable, local and remote AC measurements. (more…)