| Yes Comcast IS at Fault Had Comcast followed the rules and properly grounded the cable at the point of entry of the two homes, this would not have been an issue! Since it is a serious requirement in many jurisdictions, yes it IS Comcast's fault.
I worked in Cable television many years ago, and grounding at the point of entry was a requirement!
I now live in Mexico and have tried to convince the Cable company that they should not skimp on this requirement and they Ignore me. So now I believe I provide one of the only ground points in The Telecable Puerto Vallarta system. Unfortunately it came AFTER burning up a Motherboard on a computer with a TV tuner card connected to the Cable. The power and monitor, and all other connections were disconnected when it happened! |
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fiberguyMy views are my own.Premium
join:2005-05-20
kudos:3 | Probably good that you don't do cable work any more.
Do you know how a ground wire and ground system works? Foreign voltage on a line is removed by the path of least resistance. The ground wire must be shorter than the closest outlet, for a reason. Depending on how and where that voltage got on the line, it very well could have grounded out other than the ground.
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3 edits | Comcast screwed up the ground at my office.... My office has a cable drop that comes over to the building where it connects to a two port splitter, with one coax going upstairs and the other to the first floor via the basement. In the basement they installed a ground block, but didn't bother to connect it to anything.
I wound up connecting it to a #4 bare copper wire that's double clamped to the copper water pipe where it enters the building from the street. It's connected about 10 feet from the pipe with a number 10 wire that's about 8 feet long. There used to be about 30 volts difference between the coax shield and the building ground. Now its zero, and the 60 Hz herringbone that was on some channels is gone.... |
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2 edits | reply to fiberguy
Re: Yes Comcast IS at Fault said by fiberguy:Do you know how a ground wire and ground system works? Foreign voltage on a line is removed by the path of least resistance. SNIP Yes, you ARE exactly correct about path of least resistance, And that is why while that voltage was travelling from the coaxial shield from one house to another, it would have found 2 paths to ground (usually directly from cable shield to a ground rod near the point of entry) rather than through the neighbor's electrical system. I am sure it was a long way through the electrical system to ground, and would have been a far more direct path from coaxial shield to earth ground (had it existed).
this problem would have not occurred had the cable proper earth grounds at the points of entry on the two houses. Think about it! Each ground has an aggregate effect on the ground potential on the cable.
truth is I probably have a better understanding of grounding than you.
It is probably good that you do not have a brain anymore... |
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mworks
join:2006-06-13
Faison, NC | reply to markosjal
Also be careful of satellite tv installers.
I have come across several that think its ok, to establish another ground point close to the dish to prevent having to run a ground wire back to the houses main ground rod.
This is bad. Doing so creates a ground loop, where you now have two different ground potentials in the home. You could actually get shocked in the home if you happened to touch the case of the sat receiver and something like a lamp at the same time.
Also saw a case where the home owner couldn't get the humming noise out of his home theater. Turned out the home grounding was at fault from a sat installer. |
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3 edits | said by mworks:Also be careful of satellite tv installers. I have come across several that think its ok, to establish another ground point close to the dish to prevent having to run a ground wire back to the houses main ground rod. This is bad. Doing so creates a ground loop, where you now have two different ground potentials in the home. You could actually get shocked in the home if you happened to touch the case of the sat receiver and something like a lamp at the same time. Also saw a case where the home owner couldn't get the humming noise out of his home theater. Turned out the home grounding was at fault from a sat installer. Hey this guy knows something about grounding!Fiberguy perhaps you should listen up! Ground loop = Difference in Ground potential, however for shunting off spurious voltages it is OK. I do not believe this statement to be accuratre about the schock from appliance unless the appliance itself is not properly grounded, or has other issues. What you are referring to is an "Isolated ground" meaning that it is a ground free of other electrical noice and for most home theater / home electronics / computers is actually Preferred, and not dangerous if all grounuds are working properly.
I would Gladly place myself between any 2 good earth grounds ANY day of the week!
Man those are some bad hum bars on your TV though! |
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| reply to qworster
Re: Comcast screwed up the ground at my office.... said by qworster:....It's connected about 10 feet from the pipe with a number 10 wire that's about 8 feet long. There used to be about 30 volts difference between the coax shield and the building ground. Now its zero, and the 60 Hz herringbone that was on some channels is gone.... This is because you have reduced the voltage travelling along the cable line to ZERO by grounding it! Even if that cable is grounding through a TV for instance it may have a ground loop with a slight current travelling along it, however since it is RF it not affected by the hum as if it were an audio cable for instance.
It just goes to show the importance of grounding. If the truth be known, you probably have a neighbor with an ungrounded cable line as well that has the polarity reversed to an AC outlet, or a ground off (as in Grinding, not as in Grounding) polarized plug! That 30 volts was probably finding a home in your TV before grounding it! |
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 John GaltForward, MarchPremium
join:2004-09-30
Happy Camp
kudos:3 | reply to markosjal
Re: Yes Comcast IS at Fault said by markosjal:Yes, you ARE exactly correct about path of least resistance... Actually, it is the path of least reactance...
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A is A |
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| I assume you are speaking of inductive reactance (not capacitive reactance) because it is AC, yes that has some truth as the voltage is AC, however the point is shunt the bad stuff to ground. If necessary , Isolate the cable from your equipment by connecting two 75 ohm to 300 ohm matching transformers Back to back.
Grounding is the SAFEST method although may present its own complexities. |
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