General Technical & Safety Information

[GroundUrMast]

Here is a link that is slightly dated but still quite useful. (A few products mentioned are no longer available.)

http://www.hdtvprimer.com/ANTENNAS/basics.html

And another (even more dated) http://manuals.solidsignal.com/AntInstallGuide.pdf

The subject of bonding / grounding is one often overlooked at the risk to life and property.

http://www.antennasdirect.com/cmss_f...structions.pdf

As the title of the above document implies, the illustrations and advise are general in nature. But if you consider the drawing on the second page, the example grounding arrangement takes reasonable steps to keep fault current outside the building. ("In an electric power system, a fault is any abnormal flow of electric current. For example a short circuit is a fault in which current flow bypasses the normal load." source: http://en.wikipedia.org/wiki/Fault_%...engineering%29 )

The drawing does not illustrate a situation where the mast is distant from the electrical service ground. In that case, a solution that may be permitted in many jurisdictions would have a copper clad ground rod driven into the earth close to the antenna mast and a 6 AWG copper wire from that ground rod the building service ground. The mast ground and transmission line ground wires would then terminate on the ground rod near the antenna.

I do take exception to the phase "Optional Grounding Information" because some may construe that to mean that grounding is optional. I doubt that any code enforcement jurisdiction would agree with such a conclusion. The only recommendation I am making here is that you comply with the codes governing your lo-cal.

The document ends with several warnings. Historically the last three are the ones I've had the most difficulty heading.

And some more information:
http://www.lightningsafety.com/nlsi_...protection.pdf
http://ecmweb.com/nec/code-basics/el...io_television/

Addendum 10/25/2010: Everyone participating in the TV Fool forum does so with an agenda. I would guess that the most common would be to enjoy the benefits OTA reception due to it's economic superiority to cable and satellite service. My agenda certainly includes an economic component, I like to save money. Like the other frequent posters, my agenda also includes a desire to help others by sharing information and offering advise about OTA reception. I also want to encourage awareness of safety. As my user-name obviously implies, I have an opinion about grounding. Call me odd, you won't be the first, but I have tried to understand why the electrical code says I should ground my antenna. I have come to the conclusion that the code is not way out of line, instead it seems to me that if I choose to ground my antenna system the way the code describes, I am buying an insurance policy. With most insurance, there are limits to how much is covered. As John Candle and I have discussed this, we seem to agree that if my antenna system were to be hit by lighting, my 'insurance' would probably not be enough protection to prevent any and all harm. In the end I have concluded that I am willing to pay for the protection provided by grounding while at the same time hoping I never need the protection it offers.

A couple of TV Fool member's experiences:
http://forum.tvfool.com/showthread.p...2917#post32917 http://forum.tvfool.com/showpost.php...5&postcount=12

A couple of YouTube videos illustrating and explaining the basic concept and purpose of grounding and bonding:
https://www.youtube.com/watch?v=zLW_7TPf310
https://www.youtube.com/watch?v=iyeGqyq9kXE

[John Candle]

http://forum.tvfool.com/showthread.php?t=860

[GroundUrMast]

Originally Posted by John Candle

http://forum.tvfool.com/showthread.php?t=860

"The EASY WAY to find out about grounding in your lo-cal is to look at some Dish Network and Direct Tv installations."

"As part of a understanding and evaluation process , get some binoculars , drive around housing areas where houses are at , stop and look at Tv antennas on houses. Do any have a - separate - wire attached to the antenna that could be connected to a ground. . Think about what you have found out."

I agree. Much of what I have learned has been by observing and then pondering over what I have seen. Sometimes I learn how to do 'it' right, sometimes I learn how not to do 'it'. So I try not to jump to conclusions, giving weight to the credibility and authority of each source.

[GroundUrMast]

Originally Posted by John Candle

http://forum.tvfool.com/showthread.php?t=860

"Also think about this , some houses have metal roofs , are the metal roofs grounded with ground wires. Also think about this , some houses have metal siding , is the metal siding grounded with a ground wires?"

When I observe installation such as metal roofs and siding I see important distinctions.

Unlike a metal roof system, the antenna system enters the occupied space, therefore reasonable steps should be taken to reduce (eliminate is impossible) the possibility that a fault condition could cause hazardous voltage to be present in the occupied space or that fault current could pose a fire threat.

In the case of metal siding, I know that codes address mobile-home grounding in-part because it is not desirable to permit the siding or frame of the trailer to become energized in a fault situation.

My hope is that more people will support OTA television and enjoy it safely.

[John Candle]

Ground fault does not mean there is a faulty ground in electric circuits. Ground fault and ground fault circuit interrupters CUT OFF the flow electricity FASTER then a fuse or circuit breaker. This is to prevent damage to the electric wiring or damage to people or animals. The actual metal of the ground wire from antenna to ground or the actual metal of the coaxial cable will need to be in actual contact with the actual metal of the wire that is carrying electric current. For a 110 volt electric circuit that wire is the black wire. To (connect up)(it's a pun) a lightning strike with this stretching it a bit. . Here is my suggestion for you - GroundUrMast- , Explain in detail different situations that can make what You suggest happen and stop trying scare people with vague statements.

[GroundUrMast]

(Please note, I agree with your statement "Ground fault does not mean there is a faulty ground in electric circuits." However I am not referring to ground fault interrupters or faulty grounds. I have added a citation to my opening post that provides an explanation of the term as I am using it.)

John, I am sorry that you think I am trying to scare anyone. "The only recommendation I am making here is that you comply with the codes governing your lo-cal." I make the suggestion sincerely and in good faith.

In day to day operation, grounding will keep static charges from building up - that will reduce the possibility of electrostatic discharge damage to equipment. If that were the only thing to protect against, a light gauge grounding wire would be quite adequate.

If an energized conductor (a black wire for example) comes in contact with the antenna system (during a storm or failure of power pole due to some accident or even a faulty extension cord used near the antenna [Christmas lights for example]), then the current in the antenna system ground wire could be very high until the source of power is disconnected. The codes require relatively heavy gauge ground wire, apparently so the ground wire can carry enough current, long enough, to trip a breaker or blow a fuse. I presume that the code limits the distance an antenna ground wire may penetrate a building because, during an extreme fault condition (like the service drop wire in direct contact with the antenna system), even a 10 or 8 AWG wire could be heated to the point of failure (if that happens outside the building - bad, inside - really bad, a risk of fire in either case, but a strong reason not to run the antenna system ground inside the building if it can be avoided).

A direct hit by lighting is also an extreme situation were I would expect a code compliant installation to suffer significant damage. Still, I will sleep better if I know I have taken reasonable steps to reduce the possibility of equipment damage, electrical shock and/or fire.

[John Candle]

Some houses have partial metal roofs , houses other then mobile homes have full or partial metal siding. If a nongrounded metal roof is struck by lightning , the electric lightning is in the metal roof , the electric lightning will leave the metal roof and go where? . Also the metal vent pipes that are sticking up out of the tops metal and nonmetal roofs these are not grounded with a -separate- ground wire.

[GroundUrMast]

Originally Posted by John Candle

Some houses have partial metal roofs , houses other then mobile homes have full or partial metal siding. If a nongrounded metal roof is struck by lightning , the electric lightning is in the metal roof , the electric lightning will leave the metal roof and go where? . Also the metal vent pipes that are sticking up out of the tops metal and nonmetal roofs these are not grounded with a -separate- ground wire.

Good points & questions. However, I think that grounding of metal roofs and siding are topics for a different forum.

Perhaps http://forums.mikeholt.com/

[John Candle]

You are the one that Started this. And now You are Dancing Around. .The metal vent pipes stick up out of the roof , the top side of the roof , the metal vent pipes are not grounded with a -separate- ground wire. The metal vent pipes provide an easy path for lightning to travel to the metal housing that holds vent motors in the bath rooms , laundrey room , kitchen and etc. and etc. . The vent motors are connected to the electric wiring of the house. And then there are the metal vents that are on/in the roofs of many houses , the metal vent is on the out side/top side of the roof , these metal vents allow heat to escape out of the attic. These metal vents are not grounded with a -separate- ground wire. And then there are the many nails that have the points of the nails pointing in to the attic space , the points of these nails act as lightning directors that spray electric lightning all over the houses electric wiring that is in the attic.

[John Candle]

And what if the television antenna is mounted on a metal roof , a full metal roof or a partial metal roof? Is this now the topic for a different forum?? .

[GroundUrMast]

Originally Posted by John Candle

And what if the television antenna is mounted on a metal roof , a full metal roof or a partial metal roof? Is this now the topic for a different forum?? .

I think it's relevant enough. My personal opinion is that I would be willing to spend my money on grounding conductive stuff on my property if it's called for by the code in my lo-cal.

[John Candle]

To show how this lightning safety issue can get out of hand real quick , http://www.lightningsafety.com/nlsi_...protection.pdf and if you think you understand it 100% then go to the home page , http://www.lightningsafety.com

[John Candle]

So now as we are thinking this through , we begin to understand that lightning likes a easy path to ground. And as it shows in the Legend , the house with all the numbers around it , the house is well grounded. And lets say that the houses on both sides have no grounding , and as you remember lightning likes a easy path to ground. And at the minimum the lighting strike will melt wires , and you begin to understand that the house with the grounding is target for lighting. Not the houses on either side that have no grounding.

[John Candle]

Is lightning interested in the code at any lo-cal?? So you say to the lightning , Ok lightning , strike here , here and here , but not there , there and there because that is what the code says.

[GroundUrMast]

Anyone who reasons that a grounded antenna and mast may be attractive to atmospheric static is quite right.

However, reasoning that the antenna system will be safer if no effort is made to purposely ground and bond it, is flawed reasoning. In the case of a typical outdoor antenna installation, the antenna system is grounded the moment the coax is connected to the tuner input. This is because the coax offers a low impedance path from the antenna and mast, into the building, through the tuner and then to ground through the AC power wiring. Example cited previously: http://forum.tvfool.com/showthread.p...2917#post32917

Though the matching transformer at the antenna may offer a high resistance between the balanced input and unbalanced output, the breakdown rating of the insulating material is certainly not sufficient to stop a moderate static charge. Virtually all modern televisions employ power supply designs that provide isolation between the AC line and the chassis, but the amount of insulation used only provides safe isolation of normal power line voltages, not the high voltages that result from atmospheric activity.

If someone plugs their nice new TV into the wall, then mounts an antenna on their roof, runs the coax through the most convenient opening and then connects it to the TV, whats going to happen? In the vast majority of cases, the TV will work... for years. But for a few unlucky folks, unexpectedly, the TV just quits, because a small arc inside the tuner fried some bit of electronics (cost: repair or replace the TV). For an extremely unlucky few, a more spectacular event... perhaps a significant portion of a lighting bolt accepts the open invite to follow the coax into and through their home (cost: ????).

My point is that by choosing to run the coax from an outside antenna, the choice has been made to ground the antenna. That leaves one to consider whether it is worth spending a few dollars and maybe choosing a less convenient path for the coax run to dramatically reduce the risk of equipment damage and in a few very rare cases even protect against electrical shock or fire.

[vms]

I've read the HDTV Primer about grounding and I've been researching a lot the last few days about how to properly ground your mast, as you say. There seems to be a lot of possible scenarios that not all are discussed.

This is kind of a long post but it's hard to explain it all clearly without going into details.

My situation is that I'll likely have to install a new antenna on the back part of the house. I live in a manufactured home park and not sure yet where and how large an antenna I can erect. I was thinking that I would put it at the peak of the roof at the back. We have 3 satellite dishes that were here when we moved in a few months ago which none seem to be grounded. The entry point of the coaxial is on the side of the house. I was thinking of using that entry point in my antenna system, though I'd consider a new one if need be. I realize that the ground wire should be as straight as possible and as short as possible but I've been wrestling about what to do in my situation.

I was thinking that I would run one ground wire from the mast, under the eve(with as little bending as possible) and along the wall down toward the corner of the house and to a ground rod that will be buried there near the corner. Does this sound good so far? Along that same back wall and going around the corner would be coax which would eventually go into the house at about 17ft from the corner, which is where the grounding block would be installed.

Roughly out 10 feet from the grounding block is my electrical meter, which is on a post, which I assume there is a ground rod below it that I could attach my new ground rod(the one near the corner of house) via a grounding wire. Since all this will be outdoors, it sounds reasonable to me that that grouding wire would go underground between rods. Is that a right way to do it? If so, how deep should the ground wire be?

Back to the mast and the grounding block, I think I'm supposed to run another ground wire from the mast to the grouding block, with the coax cable, right? From the grounding block, from what I read, a ground wire is connected to the new ground rod. In my case, it would be going away from the electrical meter(at a 90-degree angle) and also back from where it came from except to a lower level. It would be actually closer and in a more linear direction(actually a 90-degree right turn) to continue through the grounding block and to the electrical meter(assuming it has a ground rod which I think it would, right?) But, I'm not sure that would be a correct way to route it. From what I read, you should run that ground wire to the new ground rod and then to the electrical meter ground rod(I guess that rod that is called the house ground).

I hope I've explained it clearly enough. So, that is what I've come up with so far and have questions about. Would there be a better way to configure all this?

Thanks

[GroundUrMast]

vms, I think of the mast ground as step one, the coax ground as step two.

Based on your description, it sounds like you are on the right track except, I would not run the mast ground to the coax ground block. I would run the mast ground to the nearest ground rod that is a part of electrical service GES (grounding electrode system). If the existing electrical service ground is quite distant from the mast location, a supplemental ground rod can be added to your existing GES. Any new ground rod needs to bond to the existing GES with #6 AWG or larger copper wire which needs to be protected from damage (the 'required' burial depth of your local code is based on factors such as freeze/thaw depth), the connectors used need to be rated for burial if they are going at or below grade. I suggest that you verify what the code calls for and use that rather than any general advise I or anyone else offers.

The second step, coax ground, ideally occurs just before the coax enters the building and close to the point were the electrical service connects to the GES (the ground rod next to your meter in your case).

Step one should provide a low impedance/resistance from the mast to ground so that if current flows in the ground conductor, little voltage difference is developed throughout the GES. Step two is the next line of defense, by using the shortest possible length of ground wire, the voltage difference between the coax shield and the GES will be held as low as possible should fault current ever flow through the coax shield. A primary goal of grounding and bonding is to minimize the voltage difference between any two 'grounded' points on the premises if there is an electrical fault.

[vms]

I see, I had one ground wire too many-the one that was running with the coax.

So, instead of running the ground wire from the grounding block to the new ground rod, I should run it to the GES? I read that the ground wire should go from the grounding block to the new ground rod, which of course is connected with the #6 AWG copper wire to the GES. Either way will work for me; I just want to make sure I have this right.

How do I find out what the codes are in my area?

Do you think that if I install one ground rod that will suffice? I was thinking of installing the first one near the corner of the house so that I would eliminate an additional bend in the ground wire.

[GroundUrMast]

Originally Posted by vms

I see, I had one ground wire too many-the one that was running with the coax.

So, instead of running the ground wire from the grounding block to the new ground rod, I should run it to the GES? I read that the ground wire should go from the grounding block to the new ground rod, which of course is connected with the #6 AWG copper wire to the GES. Either way will work for me; I just want to make sure I have this right.

How do I find out what the codes are in my area?

Do you think that if I install one ground rod that will suffice? I was thinking of installing the first one near the corner of the house so that I would eliminate an additional bend in the ground wire.

Ideally, locate the coax ground block close to the ground rod that is closest to the electrical service.

Ideally, the mast ground would connect to the same ground rod, close to the electrical service. However, you, I and many others need to locate the mast some distance away and so we expand the GES buy adding a ground rod close to the base of the mast. As I mentioned previously, all ground rods should be connected together, forming a single ground system. I can't think of a reason to add two rods... but, if you want to, cool.

http://bulk.resource.org/codes.gov/

Some cities or counties will take a phone call and be quite helpful, others seem less service oriented and more interested in revenue and heavy handed enforcement. Try for the first, without giving your name and address. If you have an unfriendly government, try investing in a beer or two with a local electrician.

[GroundUrMast]

My stock answer is, Grounding/bonding the mast and coax shield are prudent and relatively inexpensive steps that limit the buildup of static-electricity which can damage the tuner. When done correctly, grounding/bonding can also reduce the risk caused by a nearby lighting strike as well as a power line fault that would otherwise energize the antenna system.

http://forum.tvfool.com/showthread.php?t=901

Grounding/bonding in a basic system is a two step process:

1) Connect a #10 gauge copper wire to the antenna mast. A bronze ground clamp such as the Halex #36020 is well suited for this application. Run this bonding wire directly to the electrical service ground. Avoid sharp bends in the wire. (If the ground wire between the service panel and ground rod is accessible, an Intersystem Bonding Device can be placed onto the ground wire without cutting or disconnecting it. This provides a means to connect the #10 mast ground/bonding wire to the existing ground wire close to the ground rod outside the building. If possible, avoid running the new ground/bonding wire inside the building, energy from static or electrical storms is best directed to ground before it has any path into the building. The mast ground/bond wire can be bare or insulated, your choice.)

2) Run the coax from the antenna to a location close to the electrical service ground (ideally, 10' or less). Install a ground block and with another piece of #10 wire, connect it to the electrical service ground at the same point you connected the mast ground/bond.

I don't recommend short-cuts such as driving a new ground rod that is not connected to the existing electrical service ground. An isolated ground rod often has a high resistance that provides very limited ground connection. The goal is to connect to the same ground/bonding system that protects the rest of the home.

Surge protectors located inside outlet strips at the TV, computer or similar devises are worth consideration. A surge protector with a high joule rating is able to absorb more fault energy than a unit with a lower joule rating. Some surge protection units include phone jacks and F-connectors to enable protection of a phone line, coax cable and the power cable(s). However, in the case of an outdoor mounted antenna, this type of protection should not be considered a 'first-line of defence'.