I have a situation where a customer wants to introduce/hookup an single phase 3 wire 18 kVA UPS to a 3 phase 4 wire panel and the UPS will be used to power a single phase 3 wire panel. The only thing the 3 phase panel will be used for is to power the single phase UPS. The entire building is 3 phase. The UPS single phase panel will be loaded to about 11 kVA to power sensitive computerized equipment. What problems will be experienced with this type of scenerio? Phase surges, spikes or suges? Neutral over loading problems? The UPS coming on prematurely?