I've been told a quick rule of thumb for emergency generator capacity for hospitals is about 6va/square foot. (Obviously, good load calculations and historic measurements are the only way to know for sure.) This is only for doing a preliminary guess at a generator size, accurate load calcs...
I hear rumors that OSHA is going to adopt new standards that specifically mandate PPE for electrical workers, and arc flash safety procedures. Previously, they state that "proper PPE" without any real definition, is required, and they can say "well, NFPA 70E is a recognized standard, maybe you...
I have heard that IEEE-1584 suggests that 208 V systems 125 kVA and larger be evaluated for arc-flash hazard using their calculation method. I was just pouring through this document, looking for this reference. Is this implying that 208V systems under 125KVA do not need to be evaluated? Just...
Arc flash calculation methods always warn the engineer not to use too conservative a number for available fault current. If this number is too high, the arc flash hazard can look confortably low, although the real risk is higher.
However, when I call utilities, they never can provide any...
