Just as a oh-by-the-way. Screening a cable does not protect much against some types of interference. Electrical energy is carried by fields with a voltage component and a magnetic field component. Screening doesn't protect much against the magnetic component and, depending on the local impedance of space, the magnetic component can carry a lot of the energy.
With most information these days being moved in the digital domain, it is easy to produce a signal that has never been produced before. This makes testing very difficult.
After an excellent landing...