Lightning can ride into the home on ungrounded and/or unprotected cable and phone lines entering or leaving the structure. Accordingly, it should be a priority to surge protect and correctly ground all phone and cable company conductors which enter or leave the building. This includes surge protecting all phone or cable conductors as they leave and enter other buildings on the property.
Phone and coax lines should be brought into the home as close as possible to the incoming service entrance panel. Once they enter the building they are to be bonded together so that all three systems (power, phone, cable) reference the same ground potential at or near the service entrance. Since the Transient Protection Design phone and coax suppression units are designed to dump the bulk of the energy to ground, the suppressors need to be grounded, and it is advisable to provide a ground bond as short and straight as possible, using a minimum 18 to 14 AWG wire or larger. This concept provides a common reference point for incoming data and the AC power; therefore, the voltage potential between them is kept at a safe level. This is an extremely important step. If it is ignored, even the best protection equipment may not be effective. See an example design diagram here.
