How to Test an Electronic Ballast with a Digital Multimeter?

How to Test an Electronic-Ballast-with a Digital Multimeter

Do you have a problem with your ballast? Do you have a digital multimeter? Do you want to know how to test an electronic ballast with a digital multimeter?

With a digital multimeter, you can easily test and troubleshoot your ballast. It is more accurate and much easier compared with an analog multimeter.

Just a reminder though: no matter what you’re using, don’t forget to pull out the power when you’re testing your ballast. Safety first!

What Will You Need to Follow This Tutorial

Here are the tools you need to test an electronic ballast:

  • Electronic ballast ready for testing
  • Digital multimeter for measuring voltage
  • Rubber or latex gloves for keeping HID bulb safe from your skin oil
  • Screwdriver to remove the ballast from the base housing

A digital multimeter is more expensive than an analog model. But in terms of features, it is more accurate, durable, and easier to read with its LCD screen.

Although I recommend rubber or latex gloves, as long as it is non-permeable and prevents oil from adhering to the bulb surface, any type of gloves will do. In addition to protecting your HID bulb, this is also useful for protecting your hands against cuts.

Step-By-Step Instructions

How-do-I-test-an-electronic-ballast

Before we jump into the process, you need to understand what a digital multimeter is.

It is a device used to measure electrical values, like AC & DC voltage, current, and resistance. Its face is typically divided into four sections:

  • digital display – for showing the results;
  • buttons – for choosing options and other features;
  • dial – to set which measurement protocol is desired; and
  • input jacks – where the testing leads/sensors are attached to the device.

Its advantages include high digital resistance, precise reading, and no parallax error. It also comes in three types:

  • Fluke – the most basic multimeter model, generally a digital version of the analog model
  • Clamp – includes a feature that allows measurement of current without the need to plug directly on to the conductor
  • Auto-ranging multimeter – fully automatic multi-meter that automatically senses the correct measurement setting.

Now that you understand the uses and types of a multimeter, let us start the step-by-step procedure on how to test an electronic ballast.

Step 1 – Disconnect the Power

Turn off the main electric supply of your ballast. After removing the power supply, take out the fluorescent or the bulb connected to your ballast. Remember to use latex or rubber gloves when touching an HID lamp to avoid contaminating the surface.

Skin oil left on a hot HID bulb can cause it to break or burn out much faster than a clean one, so make sure that you don’t get any residue on your bulbs.

Step 2 – Uncover the Housing

Take the cover plate off to see the ballast. Then remove and label all connected wires for easy returning. Also, remove the ballast itself from the base pan of your lamp.

If you observe leaking oil or fluid, it means that the seal has been ruptured due to excessive heat.

Step 3 – Testing the ballast with a digital multimeter

Test your electronic ballast’s resistance using your digital multimeter.

To measure it, set your digital multimeter to around a thousand ohms resistance setting. Connect the black leads to the white ground wire on your ballast. Afterward, test every other wire with the red lead.

When you do this test, a good ballast will return an “open-loop” or max resistance. This means that no current travels between the ground wire and all the other wire. However, once your multimeter reading changes and starts reading current between the other wires and the ground wire, then it needs to be replaced.

To learn more, watch this video tutorial by Alex Shockley where he shows how to test your ballast.

Conclusion

Once you have finished all the steps and figured that you need a replacement, here are some brands that I recommend.

The Eballast fluorescent by Robertson is the best replacement for your fluorescent ballast; the IG13-20EL Magnetic Fluorescent Ballast by InterGlobal is an excellent choice for a low-factor ballast. Also, I recommend a list of the top 1000 watt ballasts I have tried for higher wattage needs.

Make it a habit to test your ballast before buying a new one and install it permanently in your lighting system.