Originally Posted by Nakattk;12957704
All the outside cable work was done by the cable company. All I did was hook up the inside hd box. It is the outside ground that was not done. It looks like they started to but did not finish.
Knowledge about surge protection and earthing is over 100 years old. And still mostly unknown to computer experts and cable installers.
The cable must be earthed. And not to any earthing. It must connect 'low impedance' to a single point earth ground. Every wire inside every incoming cable must connect just as short to that same earth ground.
For example, AC electric has three incoming wires. One is grounded for safety. All three must connect to that earthing electrode to have surge protection. If any one wire enters without a 'low impedance' connection, then no surge protection exists inside the building.
Low impedance is not about wire thickness. Wire must be short (ie 'less than 10 feet'). No sharp wire bends. Not inside metallic conduit. Not bundled or ty-wrapped to other non-grounding wires. No splices. All ground wires should meet at the earthing electrode. Only you are resonsible for providing a ground that both meets and exceeds post 1990 code.
You had damage because you all but invited a surge to go hunting inside the house. Once energy is inside, then nothing will avert a destructive hunt for earth via appliances. Every incoming wire (overhead or underground) must connect short to single point ground. Either directly (ie cable TV or satellite dish). Or via a 'whole house' protector (telephone, AC electric). If any one wire is not earthed, then all surge protection is compromised.
Well, some cable guys are so ill trained, that one earthed the cable to dirt in a flower box. Two recent graduates of the cable company training course were told what to do. But had no idea why. For example, the cable enters directly to TVs on the second floor. A ground wire ran from the second floor cable to earth ground. So that cable was not earthed.
A cable must drop down to single point earth ground. Make that short as possible connection from ground block to earth. Then rise up to the second floor. The 'dropping' and 'rising' sections must remain separated. But most critical is a shorter wire - not a thicker wire - to earth. So that direct lightning strikes cause no damage.
Best protection for cable means no protectors. No protector does protection. Best protection involves a wire short to earth. If any incoming utility wire cannot be earthed directly, then install something less effective. Make the same connection to earth via a protector.
Some items to examine in order to have direct lightning strikes without any damage.
And finally, what does all protection? Earth ground. Every protection layer is defined only by the earth ground. How to make any protector or that cable ground wire more effective? Upgrade your earthing. Protection is only as effective as the quality of your earth ground - what the homeowner is responsible for.
Best protection is installed before footings are poured (ie Ufer ground). In your case, better protection may mean more ten foot copper clad ground rods. Because in every case, and without exception, protection is defined by the quality of and low impedance connections to single point earth ground. Nothing else (especially not power strip or UPS protectors) does that protection.
Well that is secondary protection. Your cable company (and electric company) also install your primary protection layer. A picture demonstrates what you must inspect (and if necessary have them correct):http://www.tvtower.com/fpl.html
Only an overwhelming minority know any of this 100 years old (that well proven) science. Protection means direct lightning strikes. And you do not even know a surge existed.Edited by westom - 4/1/11 at 3:29pm