Tutor
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8 Messages
Installation Not Grounded Properly!
http://www.nbc-2.com/story/16105347/2011/11/22/more-directv-complaints-following-nbc2-investigation
http://www.nbc-2.com/story/16094308/nbc2-investigates-improper-satellite-installations
After reading/watching this story, I went out to check my connection, and realized that my connection is not properly grounded.
This is sad and disappointing. It obviously was not a profesional installation.
What should I do, contact DirecTV directly or contact the installer, I am wary to contact the installer; since he did the job the first time improperly. My install was done on 11/9 of this year.
peds48
Expert
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32K Messages
13 years ago
Call DIrecTV and get this resolved.
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dtvservicetech
Teacher
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13 Messages
13 years ago
While it is very important that your installation follow all State and Local laws, I would be very hesitant in accepting the validity of that article. Particularly the part where it said "Grounding protects home electronics from nearby lighting strikes. If a transient surge hits the dish, grounding acts like a protective shell, bypassing all of the electronics in the house."
This is absolutely FALSE. Grounding your system in no way protects against lightning. A direct lightning strike to your dish (which is extremely rare) is very likely to cause many other electronics to fail. The most common are your security system, phone, internet, garage door, and AC.
I have seen hundreds of jobs that were perfectly grounded where a nearby lightning strike caused half the electronics in the house go out.
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westom
Mentor
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36 Messages
13 years ago
This is absolutely FALSE. Grounding your system in no way protects against lightning. ...
I have seen hundreds of jobs that were perfectly grounded where a nearby lightning strike caused half the electronics in the house go out.
Too many only understand earthing according to code. Code is only for human safety. Transistor safety requires earthing that exceeds code. Earthing so that direct lightning strikes cause no damage has been understood and routine for over 100 years. And still, so many know earthing does not do protection using only observation. Because they never learned what is required also for transient protection.
COs connect a $multi-million computer to telephones all over town. Typically suffer about 100 surges with each thunderstorm. A town is without phone service for four days after a thunderstorm because nothing can protect from lightning? Nonsense. The protection even 100 years ago was earthing.
Code requires a dish to be earthed directly. Code also required the coax cable to be earthed where it enters the building. That is only for human safety.
To protect transistors, a dish must be earthed by a wire that goes straight and direct (as short as possible and without sharp bends or splices) to an eight foot ground rod. Anything shorter rod is unacceptable. Coax cable must be routed to drop down to the same earth ground used by telephone, AC electric, etc. Single point earth ground. That connection must be low impedance (ie 'less than 10 feet').
If a wire inside every incoming cable does not connect to that single point ground, then all protection is compromised. Every wire must connect either directly or via a 'whole house' protector. Only then is the earthing sufficient also for transistor safety. Only then does a transient dissipate harmlessly outside the building. Same solution exists in every facility that can never have damage. Is well proven by over 100 years of science and experience. And is too often not understood by dish installers.
This discussion better examples how a dish system should be earthed:
http://www.dbsinstall.com/diy/Grounding-1.asp
Grounding to a water pipe is unacceptable both by code and for transient protection.
A homeowner is responsible for maintaining the earth ground. That electrode does the protection. Better household transient protection means expanding/enhancing the earth ground. Protection even from direct lightning strikes means that energy is absorbed harmlessly outside. Then energy need not be inside hunting for earth via the satellite receiver or other household appliances.
If any wire (telephone, AC electric, etc) enters without an earth connection, then all protection is compromised. Earth ground defines protection. Installer must both meet and exceed code requirements - as summarized above.
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cabletech
Guru
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533 Messages
13 years ago
westom you say "same earth ground used by telephone, AC electric, etc. Single point earth ground. That connection must be low impedance (ie 'less than 10 feet'). "
Tell me, how do you get a low impedance to be less then 10 feet? Impedance is measured by ohms not feet. The ohms reading should be less then 50 ohms go main electric ground no matter where you measure.
It has always been the rule that for grounding purpose's, you have the ground block WITHIN 10 feet, but the closer the better.
I have seen ground blocks that were 30 feet from the electric but still if for did a ohm reading you got less then 50 ohms.
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westom
Mentor
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36 Messages
13 years ago
Tell me, how do you get a low impedance to be less then 10 feet? Impedance is measured by ohms not feet. The ohms reading should be less then 50 ohms go main electric ground no matter where you measure.
50 ohm characteristic impedance is a different parameter. To lower impedance to ground, a single wire (not a transmission line) must be as short as possible. No sharp bends. No splices. Not inside metallic conduit. Each can harmfully increase impedance. Routing that wire separate from other non-grounding wires is also important.
A wall receptacle safety ground is connected maybe 50 feet to a breaker box and earth ground. That wire would be less than 0.2 ohms resistance (a concern for human safety). And maybe 120 ohms impedance (a concern for transistor safety). Excessive impedance is one of many reasons why wall receptacle safety ground is not an earth ground. Another example of how earth ground must exceed code requirements to achieve a low impedance connection.
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