westom

Your computer motherboard has a digital ground. That is different from its chassis ground. That is different from a wall receptacle safety ground. That is different from a floating ground inside a TV. Different from a single point star ground that interconnects stereo equipment for no ground loops (hum). Different from a bus bar ground inside a breaker box. Different from earth ground that a breaker box connects to.

Earth ground is originally installed when a house is built. In earlier generations, the cold water pipe doubled as an earth ground. For at least 20 years now, water pipes are no long sufficient for any grounding. Earth ground must be an electrode in earth located just outside the breaker box or electric meter.

Every wire that enters your building must first connect to that ground. For example, FCC (and other) regulations require a telephone 'whole house' protector be connected to that ground where the telco's wires connect to your phone wires.

Cable TV requires no protector. That cable connects directly to earth before entering as also required by codes.

AC electric is typically three wires. Only one connects to earth typically using a bare quarter inch copper wire from the breaker box to that required earthing electrode.

Now, too many homes no longer have that earth ground. Some older homes need a newer earth ground electrode installed to meet post 1990 code requirements. A 10 foot copper clad ground rod can be purchased in Lowes, Home Depot, or numerous other places. Or ground can be upgraded by an electrician. But understand this. Only the homeowner is responsible for the existence and integrity of an earth ground.

How important is that ground? Well, a transformer wire failed. Home did not have an earth ground. So AC electric used the gas meter as an electric conductor. Fortunately nobody was home when the house exploded. Ground is essential to human safety. And then a 'whole house' protector must also make a same short (ie 'less than 10 foot') connection to earth.

A ten foot rod is one means of earthing. Another is Ufer ground. Steel rebar inside concrete footings is an even better earth ground (because concrete is a better electrical conductor). Other forms might exist. But this must always exist for both human safety and transistor safety: a short as possible connection from the breaker box (and 'whole house' protector) to a ground electrode used by all those incoming utility wires. Called a single point earth ground.

Every protection layer is defined by its earth ground. Above discusses ground for the 'secondary' protection layer. Your utility installs 'primary' protection. However too many linemen cannot be bothered to maintain their 'primary' protection ground. A picture that demonstrates what to inspect:
http://www.tvtower.com/fpl.html

Many different grounds exist. But for appliance safety, earth ground is the only ground that does surge protection. Your primary and secondary protection layers are defined by a ground installed for human safety as defined by codes. And that is installed with even shorter connections to provide transistor safety. If a protector does not have this short connection to earth, then the protector cannot do effective protection.

Appreciate another point. No soundbyte explains this well understood, 100 year old technology. So many will recommend a magic box protector. That box is easier to promote. Earth ground - not any protector – does the protection. And costs so little. But most do not know about something they cannot see. So a magic box, instead, is what so many are told to buy.