100 foot long wires are radio antennas, so at the very least you'll need to clamp high frequencies to ground at
the inputs with 1nF ceramic cap or similar. But what may be happening that knocks the chip out is spikes
from mains switching or something like that - the spikes put (parts of) the chip into CMOS latch-up. You must
prevent rogue voltages reaching the input pins. Normally a series resistor of a kohm or so with two schottky
diodes to ground and Vcc will do the job.