Boeing ran high and low voltage wiring in the same bundles. These bundles chafe in their raceways as the plane flexes and expands and contracts over thousands of takeoff and landing cycles. One of the crew members even mentions an instrument issue prior to the explosion that could be attributed to short circuiting wires. It is conceivable that the fuel quantity instruments were shorting to high voltage wiring for cabin lighting.
No its not, because and intrinsically safe sensors are fused right at the safe/unsafe barrier. Instrumentation is my life’s work, and I know it well.