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Grounding OTA / Dish / CATV / Telecom - See Post 1

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370K views 1K replies 201 participants last post by  ExDilbert 
#1 · (Edited by Moderator)
This thread has been around for almost 10 years, and so has accumulated an amazing breadth of information on proper grounding of OTA, Satellite, Cable TV, and Telecom gear. I was going through this thread again from the beginning in order to write a summary of best advice, but frankly the sheer quantity of great advice makes it too big a task. Instead, the following tip shows how to make use of the existing info here for your quick and easy reading:
Use the Search This Thread tool to the upper right beside Thread Tools and put in a search term such as "attic", or "insurance", or "lightning", or "electrical code", etc. to find highlighted posts. From there you can click on each post to follow the discussion about it at that point in the thread.​
Go ahead and give it a try! ;) As with all encyclopedic threads like this one, don't make decisions based on one or two posts or opinions! Proper grounding is far too important a topic to be treated so lightly.
 
#805 ·
There isn't much you can do in an apartment building. Tall, metal and steel buildings have building grounds installed as code. Girders are always grounded and I believe that elevators have grounding systems as well. Chances of damage are pretty slim unless you are on the top floor. Be sure to ground the coax though, either through a grounding block or power bar connected to the unit's wiring ground. Running a #10 ground back to the unit panel would be ideal but that's often not practical. Sometimes a heavier ground conductor can be picked up by attaching to the outside of an A/C or stove receptacle box.
 
#806 ·
i have 3 RG-6 quad shield cables coming down a 20 ft tower with a 10 ft mast atop. The tower is painted and attached to the cottage at the overhang. The base is pinned into the ground with 3 short rebars.

from the bottom of the tower, the 3 cables run underneath the cottage floor (raised cottage on pillars, no basement) for 40 ft, then they enter the cottage thru the flooring, into the a/b/c switch at the tv.

the cottage ground rod (4 ft) is about 20 ft away from the point where the cables enter the floor to the tv and 60 ft from the tower base

1. do i need to run ground wire between the mast and the tower itself

2. i believe 2 ground rods are required as close to the tower base as possible but separated by about 10 ft, the 2 rods need to be grounded together and to the mast with #2, is all this correct

3. generally ground blocks need to be as close as possible to the ground rods, and just before entry of the cables to the inside of the house, in this case my cables enter the house 40 ft from the tower base and eventual ground rods, so where should i place the ground blocks


thanks
 
#807 ·
OTA Grounding - Specific to my setup

Hello everyone,

I've recently installed a CM 4228HD on the side of my townhouse in Burlington. The antenna is attached with a J-pole and is mounted about 8" under the eavestrough.

From what I've read, I should ground both the antenna and the mast using copper wire, a grounding block and a grounding rod. It all seems pretty straightforward, but I have a few questions I couldn't find answers to from searching.

  1. The soil in my yard is vary hard and I don't think I will be able to drive the rod 4 feet down. Instead of this, can I connect the ground line to the copper water line that feeds my hose in the backyard? This line runs into my basement and connects to the main line.
  2. What is the potential for creating a ground loop? I've seen this term thrown around and I might be misinformed, but I thought I'd ask.
  3. Considering that I am in a busy sub-division, the antenna is not on my roof and that a lightning strike would cause serious problems grounded antenna or not, should I be worried about proper grounding?

Lastly, in case anyone is wondering, no the antenna was not up during the storm the other night :)

Thanks in advance for any input.
 
#808 ·
Before setting up the antenna on my roof a year ago I did a lot of reading and I'll summarize the recommendations:

For antennas, altitude counts for a lot, and roof mounted antennas are significantly better than attic mounted antennas. Roof mount your antenna if you can.

There is a lot of misinformation about grounding out there. I asked a couple (very smart) people who have knowledge in this area for advice (one has a PhD in physics, the other has training as an electrician) and they both said that if your house gets hit by lightning, just get the hell out. Without heroic grounding setups, grounding your antenna won't do jack in the event of a direct lightning strike. One of them said that a direct lightning strike would probably melt a 1 gauge wire.

So, lightning isn't what we are designing around. We're basically looking to shield our gear from small static shocks that your antenna will pick up. Both suggested that I should just run the coax through a grounding block, and ground it to the electrical ground in the house. The grounding loop issue will never come up this way.

If you don't properly ground your antenna the static discharges will probably fry your electronic gear that is connected to your antenna.
 
#809 ·
Thanks Audacity,

Because I am in a townhouse I cannot mount the antenna on my roof. However its current position has tested well and I am happy with the results so far.

I expected your response about grounding and from what I've read, I would agree. However, although I have not looked I think the ground for my house is out of the way and would take a lot more wire (which I've read is not preferred) and require me to run the ground across/around my patio. That's why I was looking for a second option.

Do you have any thoughts on the water line ground?

Thanks again.
 
#810 ·
As stated, there is no way to protect 100% from a direct strike. The idea of grounding is to provide an electrical path that causes minimal damage and injury. Dissipating smaller field charges (static buildup) to prevent damage or injury is another objective.

In this case, I would just run the coax through a grounding block that is attached to a cold water pipe. Position the grounding block at the point where the coax enters the building (inside or outside) and run a #10 wire to the closest cold (not hot) water pipe. Use an electrical ground clamp on the pipe. Also, make sure there is a #6 or larger ground conductor bypassing the water meter to ground the water system. A tall mast or tower requires much better grounding methods but a J-pole on the side of the building does not present a high risk.
 
#814 ·
When I was a teenager our television antenna tower got struck by lightning. It melted a hole the size of a dime in the sheet metal panel on the air conditioning unit located about 3 or 4 in away from the tower. If my memory is correct, we were no longer using the antenna by that time yet a television still got fried, I'm assuming through the cable line.
 
#815 ·
newbie attic antenna install question

I have been playing around with antennas in my attic. I basically have been trying different positions in the attic by using a pipe and then pointing the antenna for whatever I can get. The feed comes from the antenna thru a 300 to 75 ohm transformer onto coax. My question is .... does the antenna have to be grounded with a connection on the pipe or to the frame of the structure? I know there is little chance of a lightning strike but will the performance be better or worse without a ground to the frame? I dont see how it has any ground if it goes thru the matching transformer. Is it important for performance?
Any info appreciated, thanks
 
#816 ·
A coaxial cable system works by capturing external RF energy in the outer braid and grounding it out before it interferes with the centre conductor, which is where the desired signal is carried. Therefore, to remain effective, the outer braid must be grounded.

This is the primary reason for grounding coax--even for an interior install.

In terms of the antenna, an indoor antenna does not absolutely require grounding. Though it's a good idea for discharging static, etc. Attics are often humid & hot places...where charge can build up easily.
 
#817 ·
Attics are often humid & hot places...where charge can build up easily.
Humidity will help dissipate static electricity. It is in dry air that static can build up easily. That is why static tends to be a bigger problem indoors in the winter, since when you heat air, the relative humility decreases. Grounding an attic antenna doesn't hurt though.
 
#819 ·
Living in a condo unit, there was obviously no way for me to check if the coax cable connection is properly grounded which I am assuming should be. After 3 years living with the humming in my audio speakers, I finally read thru the thread and tried the cheapest suggestion for which I already have - placing the coax cable thru the surge protector input then that output thru the splitter for the cable tv and internet. Wow. Zero hum. All these years. Lol.

The surge protector which all the other components (receiver, powered speakers, cable box, etc) where connected together with the coax cable brought them all to a central point of grounding which finally eliminated the hum.

I'm so happy. Thanks everyone who contributed their thoughts on this thread!
 
#820 ·
Connection of OTA to house ground

Sorry if this is a stupid question, as I don't know much.
Everyone says to connect the ground for OTA with the main ground for the house. I understand the concept of potential difference, and that the main reason for grounding is to discharge static.
So what happens in the case of a direct lightening hit? The least path of resistance is now straight from the OTA rod into your house via the house ground. May cause fire etc.
Without the connection the path is straight to the 8' post in the ground. I guess the only issue that I don't understand is the point about differential between the OTA ground and house ground. So in case of lightening strike, the potential difference causes arching on the exterior of the home. If gas lines are not there is the issue that if someone was outside that they may get zapped? Is there anything else?
 
#821 ·
The antenna ground should be as short and direct as possible. This usually means ground rods directly below the antenna, if possible. Even towers should have a ground rod. Once you've done that, you can also run a ground wire to the house ground that the electrical panel is tied to. You'll also want a grounding block. There's a drawing near the bottom here that shows what's required.
 
#822 ·
JamesK is correct. The antenna and grounding block should be wired directly to a separate grounding rod and the ground wires kept as short as possible while staying outside the house. You then want to connect that grounding rod to your electrical ground to keep both the electrical ground and the antenna ground at the same potential.
 
#823 ·
Grounding is meant to provide a path to ground before it finds a path though construction materials or equipment. The best way to do that is to provide a grounding rod outside and a direct path to the electrical ground (water pipe or grounding system) close to the entrance point. Note that towers typically require a much more substantial external ground than data cables from antennas and other sources.
 
#824 ·
^^^^
Also, one thing I didn't care for in the diagram I linked to was the way they ran the ground to the breaker panel. If possible, it should go to where the ground enters the building, which should be where the breaker panel connects to it. Otherwise, a lightning hit could provide more of a surge to the breaker panel, due to the impedance of the breaker panel ground.
 
#825 · (Edited by Moderator)
New satellite grounding rules?

Does anyone have the newly published 2012 Canadian Electrical Code? Until now, it is my understanding that most satellite companies have been using the American NEC. As in the Bell installation instructions, it specifically references sections of the American NEC.

But this link leads me to believe that our own CSA is finally developing their own rules for grounding satellite systems under the canadian electrical code.

http://www.google.ca/url?sa=t&rct=j...9KzyDQ&usg=AFQjCNEVzElJIS0kh4BSlbvVCFxhAzH2DA
 
#826 ·
For Bell/Telus residential installations all lines should be grounded. The Dish should be grounded if it becomes the highest part of the building, otherwise grounding the Dish is not required.
 
#827 ·
That's why I want to know the actual Canadian rules. Why is Telus still hell bent on grounding the dish regardless of its mounted location with a #10 solid copper ground wire. And Bell doesn't seem to care about grounding anything.

My questions to you are as follows:

1) Why would the mast itself have to be grounded if it is secured to wood on the house, and the LNB is attached to the mast with a plastic yolk? Does this not leave the mast isolated as it is?

2) I understand the requirement for grounding the coaxial as it runs into the building. Many brands of coaxial are now available with an insulated ground messenger attached, wouldn't grounding this messenger from a coaxial ground block to the household ground be sufficient?

3) Both the USA NEC (810.21) and 2009 Canadian Electrical Code (54-200 (1)) state "the outer conductive shield of the coaxial cable shall be grounded at the building as close to the point of cable entry as possible.", but does not state if that can be on the inside of the building if there is no ground point available on the outside. Is it an acceptable practice to ground the coaxial on the inside of the building if there is no grounding point avaliable on the outside?

On a further note, the 2009 Canadian Electrical Code 54-200 (2) states: Where the outer conductive shield of a coaxial cable is grounded, no other protective device shall be required.
 
#828 ·
I think the main idea is that if the mast (and cables) gets struck by lightning you want the energy to be dispersed to a grounding point outside the home. If your grounding point is inside the home than you are bringing the energy within and risk of damage to other components in the chain as well as risk of fire.
 
#829 ·
Why is Telus still hell bent on grounding the dish regardless of its mounted location with a #10 solid copper ground wire. And Bell doesn't seem to care about grounding anything.
Did you actually read my Post.? I told you exactly what is expected of BOTH Telus & Bell.

Messenger wire is NOT a ground it is for suspension of the cable.

I could be wrong but I do not recall seeing any Messenger Cable on the Bell/Telus APL, so that would be a great reason why it would not be used......

Where the outer conductive shield of a coaxial cable is grounded, no other protective device shall be required.
Nothing wrong with a requirement actually exceeding the Code is there.?
 
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