How important are isolated grounds?
My facilities manger doesn't think I need isolated grounds in my data center. I thought they were necessary for high-performance hardware. How do I convince him I need them?
You've asked the wrong person on this one! I've been advocating against
isolated grounds in data centers for years. The fact is, unless you use very special mounting hardware on everything and take an unrealistic level of care with the installation of each piece of equipment, you will corrupt the "IG" with the first device you mount. Why? Because it has a metal chassis with a built-in safety ground (that's code) and that chassis is screwed into a metal cabinet that had better also be grounded, so you now have two ground paths: one to the standard power ground, and one to your so-called "IG." Each piece of installed equipment creates another dual-ground path, so the whole "IG" system is no longer "isolated."
"Isolated grounds" were developed for early computers that were very sensitive and were installed in an office environment where all sorts of other equipment was also connected that put electrical noise on the line. Today's boxes are much more stable, as evidenced by the fact that nearly every home has one, and power corruption problems are rarely seen. The much more sophisticated servers and storage we install in data centers does need good grounding, but that does not mean a true "isolated ground." We'll discuss this in more depth in an upcoming blog.
This was first published in November 2005