Standards About Grounding Practices of Electrical Systems

Powering and grounding an electrical equipment in the United States must, at the least, comply with regulations in the National Electrical Code (NEC). As illustrated in the CNC example in the article below, however, there are many misconceptions on the practices of power system grounding.

In fact, grounding and earthing are often confused, which is the direct cause of  many improper grounding problems that can expose the operating personnel to serious bodily harms and/or cause costly damages to your equipment.

What’s more, improper grounding can degrade the power quality and induce severe noises into sensitive electronics. It can cause your otherwise “flawless” product to misbehave embarrassingly/badly, and cost you big bucks for troubleshooting and support.

Keep in mind, NEC is to ensure safety of people and equipments. We must not violate NEC in order to remedy a performance (noise) issue. Letting a piece of equipment use an isolated earth ground rod, for example, may keep some noise issues away from your installation on a good day. But it is a common example of such violations that can have dangerous consequences.

Therefore, knowledge of proper system grounding is a critical know-how that can help improve your ROI (return on investment) of your projects.

Here are a few resources and guidelines for your quick reference.

NEC Article 250: NEC provides the minimum requirements for a safe electrical installation. Article 250 is Grounding and Bonding.

IEEE Standard 1100-2006 (IEEE Emerald Book): IEEE Recommended Practice for Powering and Grounding Electronic Equipment.

IEEE Standard 142-1991 (IEEE Green book): IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems.

To get started, here is a good article to read:

Understanding the Differences Between Bonding, Grounding, and Earthing