The other day, I was consulting for a new home being built in Old Westbury, Long Island, New York. The home was recently framed and paneled, but the electrical was not yet installed.
In an email, the owner asked for some clarity on one recommendation. Here was my email response.
Yes. Yesterday, I mentioned that my dream is to someday build our family's home and install BX cable and fiber-optic light-pipe into the walls.
First, because BX cabling provides a metal-clad pipe covering for the electrical wires and that pipe is a ground conductor, your electrical fields can be up to eight times less than the size of the electrical fields emitted by Romex (no piping) cable. This translates to someone having up to 4000 mV of Body-Skin Voltage to under 50mV, while indoors. An elevated skin voltage will stimulate the fight or flight response causing the adrenals to release cortisol, adrenaline, and norephedrine. At high skin voltages, I have seen a 100% consistency to hypothyroidism II.
Second, because BX provides a ground conductor metal sheath over the wiring, RF (radio frequency or microwave radiation) cannot easily piggy-back onto the electrical wiring. This greatly reduces EMI (electromagnetic interference, A.K.A. dirty electricity) not only on the hot wire, the resultant neutral wire, but will also help prevent the ground wire from being corrupted. This doesn't prevent EMI from forming on the hot wire but generally reduces it by at least 67%. This will provide for a better function of all electronic devices, but also because you have diminished the electric field throw, the EMI will not generally cause any issues with EMI traveling in the air. I measure this with an NFA 1000. It is the resultant of all frequencies that are not the fundamental (60 hertz) and the first 4 harmonics. Dirty electricity has been shown to cause neurological dysfunction and even breast cancer.
Third, with a lower skin voltage, you will be less affected by RF radiation due to the concept of electroporation (a modern pharmaceutical term.) Drug companies have been experimenting with administering drugs topically by increasing the skin voltage. As skin voltage increases the epidermal and dermal layers of the skin become more porous; allowing RF and toxins traveling in the air to reach the bloodstream.
Fourth, is the obvious: If any critters find themselves in the walls of your home (squirrels, field mice, etc.) they will not be able to bite through the metal piping; helping to prevent them from being killed and dying in your walls, preventing them from causing damage to the wiring which will avoid any electromagnetic build-up or potential fire.
BX cabling costs more to install and electricians sometimes belly-ache about using it, because it is heavier and slightly more cumbersome to work with, but if this were my home it would be considered essential.