Earthquake Protection of Electrical Systems

Have you done any work yourself? Or, are you wanting us to do it for you.

You could at least give us an inkling if you've even looked anywhere.

[PDF] GENERAL CONCEPTS OF EARTHQUAKE RESISTANT DESIGN

Thank you Lyn for the PDF. I wanted to hear fresh ideas and look deeper then. This one seems to be a fine starting point. I began to worry about what happens to all of those tight-fixed elements the moment the earth starts moving.

You're welcome. Unfortunately, when you don't indicate your level of knowledge, and if you have, or have not, done any preliminary research we usually duplicate effort with no reward for you, and increased frustration for us.

These things are addressed here in the US by the Uniform Building Code, UBC, and elsewhere by the International Building Code, IBC. Under the UBC, there are designations of seismic "zones" 1 through 4 that delineate the movement and torsional forces to expect. Then equipment mfrs are called upon to manufacture to those UBC zones based upon where it is going to be installed. For example here in shaky California, almost the entire state is Zone 4, so everything sold here generally meets the tilt and shake table testing requirements to meet the worst case seismic events anticipated here, which I believe to be a Richter Scale 8.0 quake lasting 5 minutes (don't quote me on that though). The testing is typically done on a machine called a Halt and Haas test table, which tilts it at all angles and shakes it at specified frequencies and g forces. How different mfrs meet these requirements is up to them, but keep in mind they also must meet ANSI and UL standards as well, in which bus bracing for faults is typically much more stringent anyway. So most of the time, seismic withstand ratings boil down to just being how the gear is bolted down and maybe extra bracing on the base to prevent having mounting bolts tear through.

As Lyn has pointed out your question is too broad. What type of building are you concerned with, and what is its use and occupancy? You can isolate your equipment from the structure, reinforce it against motion, or a combination of both techniques. As a starting point why not look back to the Cold War era design of the control rooms and bunkers used by the military, particularly the Strategic Air Command, where critical equipment was isolated by huge spring/damper systems. For a (slightly) more modern approach check out the Nuclear Regulatory Commission's seismic design requirements for critical plant electrical systems. For commercial construction start with this:

http://en.wikipedia.org/wiki/Earthquake_engineering

then look closely at the seismic requirements in the California Building Codes. After your preliminary research you'll find many members of this forum will offer their opinions/experiences to your specific questions.

Thank you RAMConsult and Lyn for your answers. I shall indeed follow your recommendations. I understand that the Califonia Building Code might be a good reference for my queries. I thought of considering the power supply architecture of let's say a complex Computer Center, for example, with its multitude and variety of systems and interdependencies.

I am sure that more specific questions may arise after my preliminary researches.