Mark, I don’t see how having a large amount of fault current available at the transformer comes into play here. 1 amp or 100,000 amps at 120 volts would result in the same damage to the modem. The resistance of the coax and electronic components in the modem greatly limits the amount of current that can flow. I have a hard time believing that even if this coax had 120 volts on it that this much damage would have been done. I would guess that the tuner in the cable modem would be destroyed but that’s it. This seems more like a lightening strike or medium voltage fault.
Curt
