3 times over the past 4 years, we've had staff be "zapped" in the ear by their 7940 phone while using the handset. In one case, the employee went immediately to the hospital, in all 3 cases the employees experienced pain for several hours. The first time this happened, TAC said our grounding at the data-rack must have been bad. We've had electricians triple-check the grounding and all is code. Since this happens so rarely and can't be deliberately reproduced, it's obviously hard to troubleshoot. The only things I can think of to do is to give the latest victim a new switchport on the switch and a new telephone set. The switch model we are using is a powered 3550. Has anyone ever heard of this before? If so, any ideas?