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GroundUrMast 19-Oct-2010 5:55 AM

General Technical & Safety Information
 
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 20-Oct-2010 4:57 PM

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

GroundUrMast 20-Oct-2010 6:45 PM

Quote:

Originally Posted by John Candle (Post 3532)
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 20-Oct-2010 7:20 PM

Quote:

Originally Posted by John Candle (Post 3532)
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 20-Oct-2010 9:41 PM

Ground fault
 
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 20-Oct-2010 11:10 PM

(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 24-Oct-2010 7:49 PM

Grounding
 
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 25-Oct-2010 8:32 AM

Quote:

Originally Posted by John Candle (Post 3624)
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 26-Oct-2010 12:03 AM

Grounding
 
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 26-Oct-2010 3:32 AM

Grounding
 
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 26-Oct-2010 7:49 PM

Quote:

Originally Posted by John Candle (Post 3649)
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 13-Nov-2010 9:48 PM

?
 
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 17-Nov-2010 8:31 PM

Grounding
 
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 17-Nov-2010 8:41 PM

Grounding
 
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 30-Nov-2010 2:46 AM

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 28-Dec-2010 11:18 PM

Help With Grounding
 
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. :D 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 29-Dec-2010 6:40 AM

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 29-Dec-2010 7:45 PM

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 30-Dec-2010 4:54 AM

Quote:

Originally Posted by vms (Post 4849)
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 25-Oct-2012 8:12 AM

If the question is, 'Should I ground my antenna?'
 
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'.

teleview 2-Dec-2013 9:45 PM

changing methods
 
+=>
-------
The changing thinking and information and the "Correctness" of grounding.

There is and was a time when separate ground rods were the Correct action.

There is and was a time when cold water pipes were the correct action to take.

There is and was a time when connecting to the electric service ground was a Big No , do not do it.

The Correct thinking changes over time.

GroundUrMast 2-Dec-2013 10:38 PM

Quote:

There is and was a time when separate ground rods were the Correct action.
Yes, then it was realized that fault current flowing in one grounding system could raise the voltage to dangerous levels relative to the separate ground system. So the current codes call for bonding to prevent dangerous voltage differences from occurring.

Examples:
Quote:

250.4 General Requirements for Grounding and Bonding.
The following general requirements identify what grounding and bonding of electrical systems are required to accomplish. The prescriptive methods contained in Article 250 shall be followed to comply with the performance requirements of this section.
(A) Grounded Systems.
(1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

FPN: An important consideration for limiting the imposed voltage is the routing of bonding and grounding conductors so that they are not any longer than necessary to complete the connection without disturbing the permanent parts of the installation and so that unnecessary bends and loops are avoided

250.50 Grounding Electrode System. All grounding electrodes as described in 250.52(A)(1) through (A)(7) that are present at each building or structure served shall be bonded together to form the grounding electrode system. Where none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A)(4) through (A)(8) shall be installed and used.

(NEC - 2008 edition)
Quote:

There is and was a time when cold water pipes were the correct action to take.
Yes, and in the case of metal pipe that is buried in earth for 10' or more, that is still a grounding electrode and needs to be bonded to any other grounding electrodes.

Example:
Quote:

250.52 Grounding Electrodes.
(A) Electrodes Permitted for Grounding.
(1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall not be used as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system.

(NEC - 2008 edition)
Quote:

There is and was a time when connecting to the electric service ground was a Big No , do not do it.
Perhaps you can cite examples of that... was that an old version of the NEC, a local interpretation/modification by a city or state or a lay persons opinion?

OTAFAN 23-Jul-2019 2:20 AM

Quote:

Quote:
Do not neglect the part about connecting the new ground rod to your service entrance ground. That insures that the two ground rods maintain the same electric potential and prevents some serious issues from occurring with voltage differentials that could cause significant problems.

Please explain specifically what "some serious issues" could be. And what you mean by "electric potential." Any past examples of what has gone wrong when you don't follow your recommendations above that you could think of, would be helpful too.

I think this would help many people understand better in "real time" what issues you are raising concern about here. It would help translate code issues into everyday life.

Thanks Tim and GroundUrMast for your input!

(The above quote was from a current thread on reception issues and I was directed by Moderator GroundUrMast to post it here along with my questions.)

GroundUrMast 23-Jul-2019 4:47 AM

OTAFAN, Thanks for inviting more discussion about this...

Electrical potential is simply the voltage difference between two objects or points in an electrical circuit.

The purpose of grounding is to provide a conductive path for current between the ‘grounded’ object and earth. In the early history of electrical distribution systems, grounding was not common. As a result, those early systems experienced problems with static build up and so would experience insulation break-down and the subsequent damage to distribution equipment and/or customer equipment when the static voltage rose too high. By connecting one of the distribution conductors to earth, the voltage difference can not rise to damaging levels on the rest of the system. An antenna system would be at similar risk if it's not grounded. The modern day electrical distribution systems in most parts of North America use the multi-grounded-neutral method which has a connection to earth at most if not every distribution station, pole, transformer and customer service entrance. This assures that even if there is a poor connection to earth at one or even many points in the system, overall, the system neutral conductor has a very low resistance (impedance) connection to the earth. As a result, there is very high confidence that static build up and the damaging effects of it can be prevented.

Bonding is not the same thing as grounding and grounding is not the same thing as bonding. However, they work together to reduce hazards. Bonding is simply connecting two or more conductive items with a conductor that has low resistance and that can safely carry current if one of the objects becomes energized through some fault or accident. If the source of fault current is from a circuit conductor, you would want the use a bonding conductor that could safely carry the current until the circuit breaker trips. This serves two purposes during the fault… First, the voltage difference between all the items bonded together remains very close to zero so if you were touching two bonded items during the fault, you wont experience a shock. Two, the fault condition generates enough current flow so as to ensure the breaker will trip and thereby disconnect what would have been a hazardous voltage on the item had it not been bonded.

The earth is a rather poor (high resistance) conductor in many areas. Here in the Northwest, we commonly encounter glacial-till (the deposits left by glaciers grinding mountains into sand and gravel). My property is pretty much glacial-till with a small amount of clay. The last time I drove a ground rod here, I applied 120 AC to it (before connecting it to any part of my existing electrical service) and then measured the current… and calculated the resistance of the rod. As I expected, that 5/8ths inch by 8 foot copper clad rod had about 1500 ohms of resistance. Pretty typical for this part of the country. That means that I would have to apply 1500 volts to that ground rod in order to make one amp of current flow. The method I used is dangerous and anyone attempting to duplicate some or all of the test just described could suffer serious injury or death.

If I were to rely on a ground rod with any significant resistance to protect my antenna system I would almost always have confidence that I was protected from static build up on the antenna system. Great… But if a nail of screw happened to be driven through a a power cable and my coax, the 120 volts shorted to my coax would not be able to force enough current into the earth to cause a fuse or circuit breaker to open… I could have 120 volts standing on the exposed part of my antenna system, including the TV connected to it. That would be an obvious shock hazard and it could remain there for an indefinite period of time.

By bonding my antenna system to the electrical service grounding system (which in turn bonds to the rest of the electrical system on my property), I can have high confidence that damaged Christmas lights or errant nails and screws can’t apply hazardous voltage to my antenna system.

For what it's worth, in my work over the years, I have encountered improperly boned/grounded systems in homes and businesses. One was a dentists office where an outlet receptacle had an open circuit neutral inside... rather than replace it, someone had connected the downstream receptacles to the the conduit in order to return circuit current to the panel. I found out when I was holding onto both sides of a loose conduit connection. Current traveled through both arms and my chest. I've also come across appliances that were wet inside and as a result, had enough leakage current through the wet insulation to make me 'wakeup'. Both examples demonstrated the danger of improper bond/ground connections. I would not have been shocked if the appliance ground had not been defeated or the conduit had not been used as a circuit conductor.

OTAFAN 23-Jul-2019 6:49 AM

Thanks for a thorough reply, GroundUrMast! I appreciate you taking the time to address this issue. And please accept my apologies, if you thought my previous post was out of place with new member John's thread. That was not my intention as I mentioned.

I'm rereading this entire thread again along with your above reply (several times now), so I can try to understand as clearly as possible this important issue better. I'll probably have more questions to ask you later as I think about this, so please be patient with my non tech background. But I think I have a grasp upon what you have written. We'll see, right?

Presently, I'm just glad you didn't turn into "Frankenstein" after the shock you received at the dentists office. Honestly, I don't know what people are thinking about when they try to "fix" such electrical issues as you mentioned. Obviously, they weren't thinking at all! I'm not a tech or electrician, but I've replaced enough outlets and such to know what not to do. And I have basic book sources to help me with related issues. And when an issue is out of my league, I call an electrician or other professional for proper help.

Anyway, I'm just trying to say that this grounding issue is too important to get into arguments over as one poster above obviously was. After some more rereading, I'll ask my questions and again, appreciate your very kind help and expertise, GroundUrMast.

JoeAZ 23-Jul-2019 12:27 PM

Lots of terrific information above. Thanks for the explanations and good detail.
I cannot help but wonder the following: If grounding as above is not feasible or
possible, would the following work??? Turn the power off to an outlet near the
tv and/or cable inside the home. Insert a grounding block or splitter if needed.
Run a 12 gauge or possibly a 10 gauge wire to the ground on the outlet. Turn
the power back on. Probably not the best scenario but would if help discharge
static electricity????

rabbit73 23-Jul-2019 2:26 PM

Equipment Leakage Current
 
1 Attachment(s)
Quote:

Originally Posted by JoeAZ (Post 61857)
I cannot help but wonder the following: If grounding as above is not feasible or possible, would the following work???

Turn the power off to an outlet near the tv and/or cable inside the home.

Insert a grounding block or splitter if needed.

Run a 12 gauge or possibly a 10 gauge wire to the ground on the outlet.

Turn the power back on.

Probably not the best scenario but would if help discharge
static electricity????

http://i.imgur.com/RT41tXx.gif

That wouldn't be according to code, but it would connect the coax shield to the house electrical system ground if done properly.

However, it wouldn't connect the mast to the house electrical system ground to drain the static charge. The code requires two 10 gauge wires connected to the house electrical system ground, one for the coax shield using the grounding block and the other for the mast.

As a temporary (only) measure, I have connected the coax shield to the house ground using a spare 3-wire plug. Of course, the outlet must be a properly wired 3-wire receptacle. Using the plug avoids messing with the receptacle wiring.

https://i.imgur.com/3UvyYuR.jpg

I have had three close calls with electrical shock, so I think it is a good idea to connect the coax shield to the house electrical system ground, even for an indoor antenna.

The antenna coax is connected to AC operated equipment. All AC operated equipment has leakage current, even when operating properly. We can't feel it because it is below our level of perception. If the equipment has a 3-wire cord and is connected to a properly wired 3-wire receptacle, any leakage current will be shunted to ground.

If the equipment has a 2-wire power cord, any leakage current will go through you to ground. If there is a defect in the equipment, grounding the coax will protect you from shock.

When I was calibrating two converter boxes, I felt a tingle when I touched the coax shield and a grounded metal strip on the counter. The antenna system had not been grounded for the tests.

https://i.imgur.com/mGa4qj0.jpg

I wanted to find out why I was being shocked, so I made some measurements with my Simpson 229 Leakage Current Tester. The meter showed almost 200 µA (200 microamperes or 0.2 mA) of leakage current.

https://i.imgur.com/qBCt9cO.jpg

When I grounded the coax with the plug shown above, the leakage current went to zero.

Details of tests in attachment.

RMinNJ 23-Jul-2019 2:59 PM

So the ground block for the coax should;

a.) Not be up by the antenna or in the house?
b.) Should not be in series with the the mast ground wire ?

What that means for me is running more coax from the antenna down near the grounding rod and where my cable TV input already has a ground block. I had always thought the best way was to put the coax directly into the house from the antenna and keep it short as possible.

GroundUrMast 23-Jul-2019 3:10 PM

OTAFAN, I'm glad you asked about this and don't think you were wrong to pose the question in the help with reception area of the forum. Just trying to maintain some organization.

GroundUrMast 23-Jul-2019 3:52 PM

Quote:

Originally Posted by RMinNJ (Post 61859)
So the ground block for the coax should;

a.) Not be up by the antenna or in the house?
b.) Should not be in series with the the mast ground wire ?

What that means for me is running more coax from the antenna down near the grounding rod and where my cable TV input already has a ground block. I had always thought the best way was to put the coax directly into the house from the antenna and keep it short as possible.

There are often competing factors to deal with. Whether it's a family member that wants the antenna to be hidden from view or keeping costs under control...

While keeping coax length to a minimum makes sense in terms of signal quality, the safety of the installation may argue for a less than ideal length of coax.

To your points specifically,

I have concluded that placement of the coax ground block very near the electrical service ground makes very good sense in most cases. Should the coax be struck by lightning or get crossed up with power, I don't want the fault current to have to travel inside the building on it's way to the ground connection. Mounting the antenna away from power lines is an obvious step that will reduce the chance of ever getting crossed up with heavy power... But if that did occur one could expect the coax to act as a fuse which is why I would take steps to make that occur outside the building. After the ground connection, I want as little coax exposed to the outside as possible. The most likely source of fault current inside the building would be from electrical branch circuits which have a breaker or fuse to limit the time a high current fault can last.

I would keep the mast ground separate from the coax ground because the sources of fault current in contact with the mast are outdoors so likely not fused. If I connect the mast to my coax, the coax will be forced to conduct some of the current if a fault exists. I'd rather provide my mast a single path to ground, entirely outside the building and with no connection to the interior.

When the mast and coax grounds come together at the electrical service ground, there is a minimum amount of resistance between each part of the antenna system and ground... Therefor, if fault current flows the voltage drop will be as low as possible.

Tim 23-Jul-2019 4:34 PM

A large static discharge is always going to take the path to ground with the least amount of resistance. That is the reason for the large ground conductors going directly to the ground rod.

As far as using the ground connection on one of the outlets in your home, I would not recommend it. The wires connected to that outlet travel through the walls of your home on the way back to the service entrance and do not provide a low impedence path to ground. You would not want that large static discharge travelling through the walls of you home with the possibility of damaging other electronic equipment connected to the wiring or even starting fires.

We are dealing with two different ground systems. The ground for your electrical system and the ground for your antenna system.

The one for your antenna system should be kept outside as much as possible and connected to the electrical system ground only at the service entrance.

OTAFAN 23-Jul-2019 11:11 PM

General Tech & Antenna Safety
 
Quote:

GroundUrMast
OTAFAN, I'm glad you asked about this and don't think you were wrong to pose the question in the help with reception area of the forum. Just trying to maintain some organization
.

Thanks, GroundUrMast. But I get it. I wasn't aware of this thread before you directed me to it and as a Moderator you were doing your job--something I would not be qualified for and I appreciate your efforts in said position.:)

Quote:

Details of tests in attachment.
Wow, I would really like to visit rabbit73s laboratory! May I come to Virginia and hang out with you, Bro???:D

Ok.....after rereading several times this thread plus today's additional posts by all you fine Techs, I think I have a better understanding of this rather complex or multifaceted subject. I would not debate the NEC since as Mr. Spock has said in the Star Trek movie franchise, "That would not be logical."

However, there appears to be some variance given for particular situations that just cannot match up with that pristine house antenna grounding diagram, that rabbit73 posted from the NEC. I wish all homes were set up to match the diagram. It would make things quite easy.

But many homes do not fit that easily into the diagram. And after reading many posts across the Net and discussions with neighbors and friends here locally, the preponderance of opinion seems to come down to, "follow the NEC as much as is practical, but if you have to make some variance do it."

For instance, you can peruse the comments from posters below on this Amazon link:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I think these folks probably represent many OTA enthusiast's across the country and for better or worse, we need to offer not only the law, or NEC in this case, but the smartest and safest options available, IMHO.

Now, there were several key points that GroundUrMast, Tim and others kept repeating in this thread. And BTW, I agree with them. Among them were keeping your antenna system grounded outside your home, separating your mast grounding from your coax and tying them both into your service entrance ground so as to keep the electrical potential resistance as low as possible. I hope I'm understanding this correctly guys, and I'm sure there was other important points too. Like I previously mentioned, I'm no tech or electrician but I think I have a fair amount of common horse sense, no offence to horses! LOL!

However, as previously mentioned above, not all if many home situations match up to the NEC. So, what is your best advice?

GroundUrMast 24-Jul-2019 5:23 AM

I suppose I've repeated myself several times in this thread...

After scanning through the comments you linked to, I came away with the impression that many people have the misconception that grounding without bonding is sufficient. It makes me recall a news item from a few years ago which reported the case of a dog being electrocuted when it touched a metal street light pole (sad situation but I'm glad that no person was injured or killed). In an effort to eliminate this hazard, the city tried installing ground rods at each of the poles in the area. However, they did not bond the metal light poles to the grounding system of the service supplying the lights. Therefor, the fault remained due to the high resistance of the new ground rods and no fuse or breaker would open due to the current to ground being lower than the fuse or breaker rating.

My take away from such examples is that any added ground rod that is not properly bonded to the rest of the system will leave people with a false sense of security. Assuming that the electrical service is already grounded correctly, additional ground rods do far less than one might expect. Bonding to the existing service ground will in almost all cases be far more effective protection from static buildup and faults to a source of power. The bottom line is, an isolated ground rod can never be depended on to do the job of of a properly sized bonding conductor... The resistance of a lone ground rod is nearly always too high for it to serve as an effective part of a bonding connection.

In the end, I'm not on a crusade to check everyone's antenna ground/bonding. I make references to the code because I believe it's based on sound reasoning and many real world case studies. My conscience wont alloy me to recommend grounding/bonding methods that don't meet the minimum standards specified in the code in your area.

OTAFAN 24-Jul-2019 5:55 AM

Quote:

I suppose I've repeated myself several times in this thread...
Sorry for having you go back to the same well again, GroundUrMast. I'm not trying to get you to say something you just cannot do, especially in good conscience. I understand better now after having reread your thread several times.

Safety first cannot be overemphasized, especially when it comes to electricity. I think your observation that many people believe grounding without bonding is sufficient is spot on. And in the end, each person will have to judge their particular situation and assume "responsibility"--oh, that's a rare concept these days!

Thanks for taking the time again to answer my questions. Time is among the most precious things we have in this life and you have been gracious with your time.

Perhaps others will chime in with any creative ideas they have, but it appears that the NEC is there for a very good reason.

rabbit73 24-Jul-2019 1:34 PM

Quote:

Originally Posted by GrounUrMast (Post 61866)
After scanning through the comments you linked to, I came away with the impression that many people have the misconception that grounding without bonding is sufficient.

My take away from such examples is that any added ground rod that is not properly bonded to the rest of the system will leave people with a false sense of security.

The bottom line is, an isolated ground rod can never be depended on to do the job of of a properly sized bonding conductor... The resistance of a lone ground rod is nearly always too high for it to serve as an effective part of a bonding connection.

In the end, I'm not on a crusade to check everyone's antenna ground/bonding. I make references to the code because I believe it's based on sound reasoning and many real world case studies. My conscience wont allow me to recommend grounding/bonding methods that don't meet the minimum standards specified in the code in your area.

Well said; my feelings exactly on the subject of grounding.

rabbit73 24-Jul-2019 2:27 PM

Quote:

Originally Posted by OTAFAN (Post 61867)
Perhaps others will chime in with any creative ideas they have, but it appears that the NEC is there for a very good reason.

The National Electrical Code, produced by the NFPA, contains guidelines for electrical safety. It is the responsibility of AHJ (Authority Having Jurisdiction), who is usually the electrical inspector, to interpret the guidelines. His interpretation then becomes the local law that is binding on the electricians and homeowners in his jurisdiction.

If you have any doubts about the correct method of grounding, the electrical inspector should be consulted. However, since some inspectors are more friendly than others, you might want to ask a local electrician first what the inspector requires.

If you want to look at the NFPA 70®, National Electrical Code®, you should be able to find a copy of the 2014 or 2017 Code in the reference section of your local library. The Code is difficult reading because it uses special language aimed at electrical professionals. ARTICLE 810 is about Radio and Television Equipment (OTA) and ARTICLE 820 is about Community Antenna Television and Radio Distribution Systems (Cable).

If you want to learn more about the controversial topic of grounding, take a look at this reference:
Antenna System Bonding and Grounding Requirements in the USA
Whitham D. Reeve (© 2012 W. Reeve)

http://www.reeve.com/Documents/Artic...quirements.pdf

see also:
Satellite System Grounding
Part 2 - NEC Overview
Presented by Todd Humphrey
http://www.dbsinstall.com/diy/Grounding-2.asp

Todd Humphrey doesn't speak for the NFPA that publishes the NEC code, but he has some ideas that are helpful.

The latest device to make connections to the house ground is the ERICO IBTB. It has a lay-in clamp for the house ground wire which must never be disconnected when your electrical system is energized:

https://i.imgur.com/jOLzHcG.jpg

https://i.imgur.com/ffKm9j1.jpg

This Old House on PBS showed one being installed.

OTAFAN 24-Jul-2019 11:14 PM

Thanks for the above references, rabbit!

I've printed them off for my files. They will be quite helpful regarding these grounding issues, et al.

I'm very glad you fine Techs are here on TV Fool, so that many of us across the country can continue to enjoy OTA TV safely, save money and all that goes along with these matters!

All the best as always.....

GroundUrMast 2-Aug-2019 1:37 AM

Here is the 20017 edition of the NEC (NFPA-70). Chapter 8, Article 810 is the primary portion that deals with antenna systems used for TV and Satellite reception.

https://www.tooltexas.org/wp-content...NEC-Code-2.pdf (7.4 MB)

rickbb 2-Aug-2019 5:59 PM

One thing this post shows is, I've done it wrong and now get to correct it. :(

OTAFAN 11-Aug-2019 12:13 AM

General Tech & Antenna Safety
 
Can an antenna ground stake be checked for resistance with a multimeter, or would one have to use the expensive test equipment with multiple leads as seen on various websites discussing ground testing?

And if one could use their multimeter, where would the leads be placed for resistance reading?

Thanks in advance for any kind help!


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