Surge Protection Anthology, All Papers - Part 8, Coordination of cascaded surge-protective devices

CaCiiuAing ~lt.0 ,~,o;-e s;irge-pi-o;efiiiie devices located r p y ~ c t i ~ ~ l y rrt the serl@ce e ! ! ~ m c e c>f CI building ar~d near the sensitive equipment is intended to ensure that each device shares the surge stress in an manner commensurate with its rating, to achieve reliable protection of equipment against surges impinging fi-om the utility supply as well as internally generated surges. However, depending upon the relative clamping voltages of the two devices, their separation distance, and the waveform of the impinging surge, coordination may or may not be effective. Ihe paper reports computations confirmed by measurements of the energy deposited in the devices for combinations of these three parameters.