The repaired conductor must be Megged.
Aluminum is at extreme hazard when in contact with the earth.
It corrodes ENDLESSLY in the presence of chlorides. ( table salt )
Unless you used epoxy encapsulation -- you shouldn't trust your underground repair.
The light is controlled by a photo-eye. That's what's dropping out the lamp. It can change its logical state in microseconds. Ordinary field test equipment is not going to spot that.
