High Capacity Amperage Measurement

We had a situation a few months back where we needed to monitor amperage on a grocery store panel over a period of time. The trouble was that we needed data-logging capability AND accurate measurement at 600+ amps.

Finding an all-in-one solution proved to be quite expensive. Luckily, my friend Jim Bergmann happens to own an instrument company (Redfish Instruments), and he had a simple solution.

Use the data-logging capability of the Redfish multimeter with a Fluke I800 amperage to mA (milliamp) clamp to get the job done.

You can use this particular clamp with any good-quality meter that reads in the milliamp range (not to be confused with μA, which is microamps, often used for testing flame rectification).

For this clamp, you connect the meter leads to the correct jacks and select the mA scale, as shown below. In this particular case, 1mA = 1A, so the image below is showing a 320-amp measurement.

There are other accessory clamps that use the mV (Millivolt) scale rather than mA, like the Redfish IDVM333 shown below.

With this clamp, the output scale can be adjusted with the selector on the clamp to either 10mV AC or 1mV AC.

Again, you need to make sure the leads are in the right spots based on the type of clamp reading and set it to the right scale. However, once you understand how to do it, it's surprisingly simple, and you can use a wide variety of clamps and meters.


Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Related Tech Tips

What I’ve Learned From Teaching in a Trade School
I have been teaching at my local trade school as an HVAC instructor for the past year. It’s been a much different experience than training a technician on the job. Some of the students are already working in the field, and others have never been in an attic or crawl space. But regardless of experience […]
Read more
Trades and the Skills Gap - A Manifesto
This article is a year old, and I'm recycling it because it's on my mind today. I had a fun conversation with Richard Trethewey on the podcast that has me thinking along these lines today. The link is HERE if the player isn't showing up. I have a confession to make. I'm a bit of […]
Read more
Entropy in Refrigeration and Air Conditioning
In the trade, we talk a lot about changes in enthalpy, especially when we are looking at total heat exchange over an evaporator. Sometimes, you will bump into the word entropy, and I wanted to take a stab at making it more understandable. Many people understand entropy as the condition in which molecules become more […]
Read more

To continue you need to agree to our terms.

The HVAC School site, podcast and daily tech tips
Made possible by Generous support from