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Thread: Lack of grounding-bonding near DP on a condo

  1. #1
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    Sep 2017
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    Casselberry, FL, US
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    Lack of grounding-bonding near DP on a condo

    Hello everyone, this thread is related to the condo where I live. I experience very bad lightning surges, lost a number of equipment already (three sets of cable company's setbox and modem, twotelevisions, one gaming console, one blu-ray player and one multi-channel AVreceiver) within 1,5 years and I suspect that it is related to grounding and bonding issues. I use a surge protector, and after a thorough investigation and analysis of the lost electronics, I was able to successfully trace the problem back to the coaxial cables. I let the cable company know about it, they claimed they meet NEC-requirements. However, I suspect they do not. Did quite a research in the NEC and according to that, I would have to say that at least the cables at the the Demarc Point need to be grounded with a ground block and electrode or rod, and bonded back to the main ground .

    My questions:

    • Does the installation shown on the pictures meet NEC-requirements?
    • If not, what else needs to be added and done to the installation to meet requirements?


    Apparently, I will not fix this myself, considering the facts that the cables belong to the cable company and I assume I cannot make modifications on them, but this represents a safety hazard in my home and I want someone to put an end to this.

    I also do not know who to contact if the cable company won't be willing to fix the issue here if they are breaking the NEC.

    Thank you!

    Ps.: Sorry about the word "pipe" in the pictures, I meant conduit! And I also can provide pictures of the attic if needed, but the cables just simply enter.
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  2. #2
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    Welcome. Your demarc is the box down low, not the one up high. Code requires the coax be bonded at the demarc; this is usually done via a green #14 run from the first splitter back to the panel. What you have looks correct tho what I need to see is not pictured (a bare or green wire coming from the first splitter/barrel connector to the service).

    Grounding coax will not stop surges. You need a surge protector for coax, and that is no guarantee to stop surges either.

    Interestingly enough, 30+ years ago when this neighborhood was cabled, the cable co. drove a 5' rod at the demarc, hooked a 3' piece of #14 from it to the first splitter, and called it a day. Never seen the first fried electrical component from this. Bonding the cable to the service is a bad idea imo but I'll never get the code changed so whatev..

    btw, in pic #7, the cables touching the metal conduit arent an issue. If that was taking a lightning surge I'd expect to see scorch marks.
    Electricians do it until it Hertz!

  3. #3
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    Quote Originally Posted by JFletcher View Post
    Welcome. Your demarc is the box down low, not the one up high. Code requires the coax be bonded at the demarc; this is usually done via a green #14 run from the first splitter back to the panel. What you have looks correct tho what I need to see is not pictured (a bare or green wire coming from the first splitter/barrel connector to the service).

    Grounding coax will not stop surges. You need a surge protector for coax, and that is no guarantee to stop surges either.

    Interestingly enough, 30+ years ago when this neighborhood was cabled, the cable co. drove a 5' rod at the demarc, hooked a 3' piece of #14 from it to the first splitter, and called it a day. Never seen the first fried electrical component from this. Bonding the cable to the service is a bad idea imo but I'll never get the code changed so whatev..

    btw, in pic #7, the cables touching the metal conduit arent an issue. If that was taking a lightning surge I'd expect to see scorch marks.
    Thank you so much for the fast response, JFletcher!

    Seems like I will have a bunch of additional questions. You said the demarc is the cable box down below, for some reason I thought that that is the Network Interface Device (NID).

    I relied on NEC Article 820 that says "the metallic sheath of CATV cable entering a building or structure must be grounded to the earth as close as practicable to the point of entrance to the building or structure" [820.33]. And the Demarcation Point (or point of entry???) was defined as the point where the cable company's cables are entering the premises of the customer's structure.

    So what is the deal here then? I don't seem to get it.

    I posted a picture for you to see clearly. Here you can see the new ground that we added and put it next to my condo's splitter, the old one in the background goes down into the ground and comes up in that green connection hub or whatever box that you can see on pic 2. We added the new ground because we could not determine whether the old one is connected to the power company's electrical meter underground somewhere or not.

    So you think the way these cables are is normal?

    Thank you so much again
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  4. #4
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    The demarcation point and the NID are one in the same. Where utility meets customer wiring. Can be in the pedestal, or box on the side of the house.

    I would not have two ground wires to separate points from that splitter. I know it's a pita to see if the one ground goes back to your panel or service, or to a local rod then a #6 to the service, but a second ground is not the answer. It is liable to make things worse with ground loops.

    If you've lost as much equipment as you say in the last 18 months, you need surge protectors on your coax. Grounding and bonding will not solve any problems with lightning strikes. If your coax eats a 500kV+ lightning strike, no amount of copper grounded or bonded to anything is going to save your equipment.

    I know you want a 'it's the cable co's problem' answer, but I think everyone here is going to recommend surge suppression for your coax vs more/alternate grounding/bonding of your cable. I actually consider an isolated coax system more reliable than bonded to the service, so even if that green ground wire dies in the ground (i.e, isn't connected to squat) you're still better ahead imho.

    The reason for that is if you lose a service neutral, and the coax is (properly, new code-wise) bonded to the panel, your coax acts as the neutral (because the cable co and POCO share grounds) and tends to melt, causing all sorts of other problems.

    tl;dr: get surge suppresors for your coax at the equipment. What you have is a pretty clean and *apparently* code-compliant install.
    Electricians do it until it Hertz!

  5. #5
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    Quote Originally Posted by JFletcher View Post
    The demarcation point and the NID are one in the same. Where utility meets customer wiring. Can be in the pedestal, or box on the side of the house.

    I would not have two ground wires to separate points from that splitter. I know it's a pita to see if the one ground goes back to your panel or service, or to a local rod then a #6 to the service, but a second ground is not the answer. It is liable to make things worse with ground loops.

    If you've lost as much equipment as you say in the last 18 months, you need surge protectors on your coax. Grounding and bonding will not solve any problems with lightning strikes. If your coax eats a 500kV+ lightning strike, no amount of copper grounded or bonded to anything is going to save your equipment.

    I know you want a 'it's the cable co's problem' answer, but I think everyone here is going to recommend surge suppression for your coax vs more/alternate grounding/bonding of your cable. I actually consider an isolated coax system more reliable than bonded to the service, so even if that green ground wire dies in the ground (i.e, isn't connected to squat) you're still better ahead imho.

    The reason for that is if you lose a service neutral, and the coax is (properly, new code-wise) bonded to the panel, your coax acts as the neutral (because the cable co and POCO share grounds) and tends to melt, causing all sorts of other problems.

    tl;dr: get surge suppresors for your coax at the equipment. What you have is a pretty clean and *apparently* code-compliant install.
    Thank you for your answer!

    What kind of coax surge protection would you suggest? Is there any device that I would be able to install in that gray junction box for instance?

    I actually do have surge protector (APC H15 Power Conditioner), and the coax is plugged into it by now. The only reason why it was not plugged in before was that the cable company suggested not to plug it in, because it could cause interference with the signal. Hell, if I only knew before that all the problems were related to it, I would not mind plugging it in at all!

    Also, the power company advised that for a one-time initial installation fee ($44 or so), they can provide me some sort of surge protection (possibly their conditioner), and for a low monthly fee ($4.99 per month for up to $1,000 damage per year) they will reimburse me if something like this happens. In my situation, it is worth considering, I think. Or maybe not, who knows!

    You seemed to be familiar with the place I live at. Did you live or work here before?

  6. #6
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    I have to tell you, those spikes were probably not that bad at all and could have been stopped by a surge protector, they were just enough to fry the HDMI ports on all my equipment. Which is, if you think about it, gives you the same results - costly repairs or new equipment.

    Is this something worth considering?

  7. #7
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    I would ask the cable company what they recommend and where. A suppresor like what you linked would be installed ahead of the first splitter in that box, yes. I dont have a particular product in mind (I dont deal with lightning damaged equipment often - maybe a call a year here). At the rate you are losing electronics, the cable co's offer may be your best bet. Your APC H15 is pretty high end; if that doesn't do it, I dont know what will. Yes, they can occasionally cause signal problems but if you're not experiencing any, or slow internet, leave it in place.

    You may also want to call out a licensed electrician to check your service neutral as one going bad can cause voltage imbalances on your branch wiring and also fry electronics. That's because the a) current is looking for a path back to the source and can go thru your coax and b) your 120V loads like TVs are no longer operating at 120V in parallel, but at 240V in series. If you've had anything else blow out, or notice lights dimming/going brighter, then you'll want to make that call sooner than later.

    Never been to your place - the pictures you provided were great! Do you happen to have one of the burned out HDMI ports?
    Electricians do it until it Hertz!

  8. #8
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    Quote Originally Posted by JFletcher View Post
    I would ask the cable company what they recommend and where. A suppresor like what you linked would be installed ahead of the first splitter in that box, yes. I dont have a particular product in mind (I dont deal with lightning damaged equipment often - maybe a call a year here). At the rate you are losing electronics, the cable co's offer may be your best bet. Your APC H15 is pretty high end; if that doesn't do it, I dont know what will. Yes, they can occasionally cause signal problems but if you're not experiencing any, or slow internet, leave it in place.

    You may also want to call out a licensed electrician to check your service neutral as one going bad can cause voltage imbalances on your branch wiring and also fry electronics. That's because the a) current is looking for a path back to the source and can go thru your coax and b) your 120V loads like TVs are no longer operating at 120V in parallel, but at 240V in series. If you've had anything else blow out, or notice lights dimming/going brighter, then you'll want to make that call sooner than later.

    Never been to your place - the pictures you provided were great! Do you happen to have one of the burned out HDMI ports?
    I am afraid that the cable company is going to be a dead end. After this, they would never say anything except that I should be fine because they meet requirements. And besides that, "Act of Nature", of course.

    Ahead of the first splitter, you mean in the DP or that little box on the side of the house?

    Thank you, tried my best with the pics. And yes, I actually have the dead Main Board of my TV and I also have the fried HDMI Assy for the AV receiver.

  9. #9
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    This being an internet forum I am surprised that you don't yet have 14 different opinions from 6 different posters

    You absolutely _must_ bond the cable system shield to the electrical system ground. Code requires this, but there is actually a very good reason.

    When lightning strikes, huge currents flow through the Earth. When you have two systems with _separate_ grounding electrodes, then these earth currents can flow into one grounding electrode system, through your equipment, and out the other grounding electrode system. You want these currents to stay in the grounding electrode system, passing through your bonding jumpers.

    I understand the issue that JFletcher raises; the multiple neutral-ground bonds between neighbor's services can mean that an open neutral at one home can cause current flow on things like water pipes and co-ax shields. IMHO this is a real problem, but the solution is not isolated grounding electrodes.

    -Jon

  10. #10
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    Quote Originally Posted by winnie View Post
    This being an internet forum I am surprised that you don't yet have 14 different opinions from 6 different posters

    You absolutely _must_ bond the cable system shield to the electrical system ground. Code requires this, but there is actually a very good reason.

    When lightning strikes, huge currents flow through the Earth. When you have two systems with _separate_ grounding electrodes, then these earth currents can flow into one grounding electrode system, through your equipment, and out the other grounding electrode system. You want these currents to stay in the grounding electrode system, passing through your bonding jumpers.

    I understand the issue that JFletcher raises; the multiple neutral-ground bonds between neighbor's services can mean that an open neutral at one home can cause current flow on things like water pipes and co-ax shields. IMHO this is a real problem, but the solution is not isolated grounding electrodes.

    -Jon
    Thanks for the reply, Jon!

    Are you saying that the splitter in the cable box has to be grounded and bonded back to the electrical? Because it is, that is what we did with that ground cable. Or are you talking about the ones in the box on the side of the house? Pardon my stupidity.

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