I am a facilityt engineer in Newtown, Pa. After moving into our NEW building, many 277v, T8 electronic ballasts were found to be bad, about 15 out of 300. Since September, about 20 more have gone bad. It's a commercial office building, 30,000 sq. ft., with about 50 computers. There is a separate server room on a K-rated transformer. There are 2 TVSS surge suppressors installed, one on the feed to the server room and one at the MDP. Several personal UPS devices have failed or malfunctioned. I had a survey of the Main Distribution Panel conducted, but it only found about 2% THD, and about 25% current distortion, the only construction issue was bonding in the service entrance to MDP. We also have 4 air handling units each with it's own VFD, 2-10 hp and 2-15 hp motors. They are experiencing about 110% harmonic current, most 5th and 7th. Wondering what to do next?
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