"None were grounded." Grounding of a fleet is quite rare. Normal proceedure, if a maintenance problem is suspected (and aging/frayed wiring would be an example) then an AD is issued requiring inspection/repair within a specified number of flight hours.
"No history of it happening previous." There most certainly was.
"Never happened since." While I am not aware of any, there may have been. However, there has been increased inspection, changed tanking proceedures, and in the case of new build, different design criteria.
"Although there have been wiring/electronic upgrades, none related to that incident."
Tank protection most certainly has been, and continues to be an issue, both on in-service and developmental aircraft. In fact Lockheed Martin is struggling with tank issues on the F-35, needing nitrogen purging as an interim measure until a fix is found. And this is acknowledged to be the most sophisticated aircraft ever built.
So, tanks can, have, and will blow up.
Please see my post # 73.