A Guide to High Resistance Grounding
Part 1 of 4: Power System Grounding Basics
Download Part 1
We received a most interesting four-part document, A Guide to High Resistance Grounding, from I-Gard, a Canadian manufacturer of power resistors, that details the rationale behind low- and high-impedance grounding as well as how to size out the resistance that makes it work.
Having had some occasion to peruse the National Electric Code, many of us know that to be in compliance, we have to be sure, in a high-impedance grounded system, that it is a three-phase ac system of 480 to 1000 volts where conditions of maintenance and supervision ensure that only qualified persons service the installation, continuity of power is required, ground detectors are installed on the system and line-to-neutral loads are not served.
I-Gard’s Guide is conveniently organized into four parts:
- Part 1 covers Power System Grounding Basics
- Part 2 covers the Disadvantages of Delta Ungrounded Power Systems
- Part 3 covers High Resistance Grounding Basics
- Part 4 covers Sizing of the Neutral Grounding Resistor
I-Gard has filled in a lot of background information for us in simple tutorial form. We will be offering this four-part download free of charge beginning now with the first part, which deals with some of the basics of system grounding, what constitutes a ground fault, and why it needs to be addressed.
Click here or on the image above to download Part 1 of this document.
Stay tuned for Parts 2 through 4 being sent over the next 3 months.
