Grounding a dish

Let me start over again.

My house is 35 years old with a 3 wire grounded electrical system. The dish is on the opposite side of the house from the service. The service is around 30 ft, the way the rat crawls, from the dish that is mounted on a banded bracket made especially for a chimney installation. The only way from the dish to the service is either over the house or through the attic. The short side around the house has a carport/driveway blocking burial. The back of the house is south where the chimney is.

What should have the installer done when he installed the dish to have the free professional installation that the dish package claims to come with?

The cheap way out for the dish system would be to mount the dish in my front yard but since I still have CATV as an option this is out of the question. The dish goes on my chimney or it just goes away.

Here is a link to the instruction manual that comes with the dish. I assume that the offer from dish makes them required to install the dish to meet the requirements of the owners manual.

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Reply to
Kilowatt
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In an earlier post you said you have a disability and have 15 years experience as an IBEW member. Is your disability a mental one? Because your question was answered in previous posts. So what is your problem? Can you read? Do you have a HS diploma?

Reply to
Mr. Smith

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Assuming it complies with manufacturer's instructions, look for a #10 (or fatter) copper or #8 (or fatter) aluminum conductor run either inside or outside the building in as straight a line as practical from the antenna to the service panel. If you have that connection, it meets code. If not, it still might - read on.

Dunno what the installer should have done with respect to grounding - the manual at the link you posted does not include page 94 (stops at page 17). According to the table of contents, grounding information appears on page 94. The National Electrical Code (NEC) requires that manufacturer's instructions be followed.

However, I can answer in general. Per the NEC, the grounding conductor must be connected to the home's grounding as follows (from 1999 NEC 810-21f) "1. To the nearest accessible location on the following: a. The building or structure grounding electrode system as covered in Section 250-50 b. The grounded interior metal water piping system as covered in Section 250-104(a) c. The power service accessible means external to enclosures as covered in Section 250-92(b) d. The metallic power service raceway e. The service equipment enclosure, or f. The grounding electrode conductor or the grounding electrode conductor metal enclosures; or" What follows the word or in the sentence above is for an ungrounded system. In addition from 810-21 g & h: (g) "The grounding conductor shall be permitted to be run either inside or outside the building." (h) "The grounding conductor shall not be smaller than No. 10 copper, No. 8 aluminum, or No. 17 copper-clad steel or bronze."

So the installer has to follow the instructions we can't see on the link you posted, as well as article 810-21.

He should follow the current code in use in your community, which could be the 2002 NEC. That changes b. and c. above to: b. The grounded interior metal water piping systems, within 1.52 m (5 ft) from its point of entrance to the building, as covered in 250.52 c. The power service accessible means external to the building, as covered in 250.94 as covered in Section 250-92(b)

Reply to
ehsjr

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I hope you don't mind if I get a second opinion. If you do mind then it is something you have to deal with.

Reply to
Kilowatt

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This kind of reminds me of reading the tax code again. How about the plumber recommending acid for cleaning pipes?

I didn't check for page 94 because all it really says is to install per NEC

810-40. The safety instructions on page vi have more of a visual of what is required. I really have read this section more than once but I have never finished it without my eyes glazing over and going into a trance. :)

I can read all this and I am a Journeyman Electrician. I am convinced that driving a ground below the dish meets the requirements. I am however concerned that another connection from the new ground rod back to the service might be required. I am sure this connection would be better but I am less convinced that it is necessary.

I do understand that attaching a grounding conductor to the inside of the house to pipe would make a proper ground but would do very little in case of lightening. They install satellite dishes every day an I know of no one yet that has ordered the lightning protection as part of the install package.

I guess my new question should be.......how are they installing these dishes every day without all this controversy? I know they ain't getting put in according to NEC 810-40.

Reply to
Kilowatt

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The link you posted does not contain the installation instructions, to be followed regardless of any advice given here, but if it helps at all:

I don't know what happens in the US (maybe the laws of physics are different there ;-), but all microwave/radar/satellite dishes I have ever seen are definitely *not* grounded at the dish itself.

Let me explain why: The dish is typically connected to the receiver using coaxial cable. The outer braid of this cable is connected to the dish at one end and the receiver at the other end.

Because of the high frequencies involved, the receiver circuitry is typically installed in a metal case, earthed to the supply earth via a standard 3-pin power cable. If you were to earth the dish as well as the receiver, you could (amongst other things) set up a ground loop in the coaxial cable which would interfere with the received signal.

Because proper earthing is essential to minimise interference, many receivers have a separate ground lug on the outside of the receiver case - and it is this lug which should be connected to a good earth point.

If you are worried about lightning strike (a separate issue) you can purchase and install in-line surge filters on the coaxial cable near the receiver end. Some receivers have built-in surge proitection - and obviously if you earth the dish, this won't work.

I hope this helps, Cameron:-)

Reply to
Cameron Dorrough

Lightning has traveled how many miles through non-conductive air? Now lightning will be stopped by a silly little 'surge filter' when miles of air could not? Appreciate the technical fiction of surge filters.

If a surge 'filter' is on cable, then a dish signal is also filtered - stopped. Obviously, surge 'filters' don't exist. They are not filters. Transient protection devices are shunt mode devices - not filters. But the fiction sells protection devices at excessive price. Too many really don't know what a surge protector (surge filter) really does.

"proper earthing is essential to minimise interference" just is not true. Grounding to receiver case minimizes interference. Grounding and earthing are separate functions. Furthermore, that long connection from receptable safety ground to earth is not an earthing connection at frequencies being discussed. Long wire instead is an antenna (at frequencies being discussed) that would only receive more interference.

Earthing and grounding are separate issues that often share same wires. Earthing is not for interference. Earthing is for safety - both human and transistor.

That external ground lug permits single point grounding of adjacent equipment as a solution to ground loop problems. Ground loop solution also does not involve earthing. For effective earthing, incoming wire must make a less than 3 meter (10 foot) connection to single point ground. That receptacle safety ground has too many sharp bends, too many splices, is bundled with too many other wires, and is too long to be an effective earth ground. That receptacle ground is for human safety - a connection to breaker box.

Again, if it was a "surge filter", then it would also filter out dish signals. In real world transient protection, there is no filter. There are shunts to earth - which plug-in protector manufacturers don't want understood to sell their ineffective devices. Effective surge protectors are only temporary connections to earth ground - if properly installed with a less than 10 foot connection to earth. There is no effective surge filter. And there is no effective earthing in a wall receptacle.

This and kilowatt's questi> The link you posted does not contain the installation instructions,

Reply to
w_tom

Zero. Zilch.

It might have travelled quite some distance through ionised air.

Reply to
Airy R. Bean

Reply to
w_tom

And what would be the mechanism of destruction?

Electrostatic breakdown causing ionisation, perhaps?

Reply to
Airy R. Bean

I have learned to ask the question is a more simple manner. The instructions that come with the dish say to ground the dish according to NEC 810-40. My thought is that dishes are being installed every day. If I pose no restrictions on the installer and just tell him here is the TV make it work.

How many installs per year are installed in a professional manner. Since the instruction booklet even has a section to "remind" the installer to install the dish according to NEC810-40 I would say this would be a requirement of the free install.

It don't happen.

FYI. Just because this has been asked more than once doesn't mean it is a redundant conversation. When you get one yes and one no to the same question that kind of makes room for a little more discussion.

Want to talk about abortion? Want to settle that today too?

Reply to
Kilowatt

The "surge filters" I am thinking of (yes, that is what they are called) consist of a series impedance (usually a small inductor) with gas discharge devices and metal-oxide varistors (MOVs) on either end to shunt any surge to earth. The other way to protect a dish is to use a tuned 1/4-wave stub, configured to be transparent at the selected operating frequency whilst offering a short circuit path to earth for a lightning strike.

You usually need a combination of both types for full protection, and neither one will protect the cable on a direct hit - only the equipment it is connected to (yet another reason not to earth the dish).

Have a read of

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The devices I have used on similar applications are the CN-90 and CN12-STUB.

Cameron:-)

Reply to
Cameron Dorrough

I don't live in the US and am not familiar with the code you mention, but:

Assuming this code *is not* specific to the installation of dishes on houses, over here it is common practice to require installers to comply with relevant Wiring Rules / local Regulations when installing *any* item of electrical equipment.

The sole reason for doing that is to protect the manufacturer's collective butt when someone who is not properly trained and doesn't know what they are doing installs something "in an unsafe manner" and burns the house downs and/or kills someone.

This has nothing to do with earthing or anything else - the Manufacturer's Instructions should cover that. If they don't then it is not required. End of story.

Reply to
Cameron Dorrough

You don't live in the USA and you don't know what the code section says but you some how feel you have said all that needs to be said. End of story.

Forgive me but that is bullshit. End of story. PLONK

Reply to
Kilowatt

You haven't learned anything!

Manufacturer's

Forgive me for trying to assist a self-opinionated yankee troll. End of story.

Cameron:-)

Reply to
Cameron Dorrough

See 810.21F. An isolated ground rod is not one of the allowed methods unless there is no other grounding means. For good reason too. You don't want to be electrically in between the two grounds (like when changing out home theater components) when a fault occurs. "Professional Dish installers" have not gone through an electrical apprenticeship program, and are satisfied when the signal strength looks good. Guess they haven't been sued yet.

The metallic water pipe is also no good unless you catch it near its entrance.

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Reply to
Steve Alexanderson

A filter can be designed to pass at one frequency spectrum, and block or shunt at others. Perhaps "filter" is a poor terminology choice, but there are series mode surge suppressors, or transient protectors, available that filter or absorb damaging voltage excursions and RF from electrical circuits they are applied to. A simple description of them would be a lc filter in various forms depending on the supplier.

I too share your distain for the commonly available shunt mode surge suppressors. I believe in most applications they cause more damage than good. As you so correctly describe, shunting extreme voltage excursions to an equipment grounding conductor great distances from the earth ground point is very undesirable, and frequently results in severe damage. Additionally as you also point out, having a defective or improperly effected single point earth ground for a system is particularly hazardous, and results in the other efforts to protect against lighting/surge activity being for the most part ineffectual.

I have evaluated a large number of transient or surge protection devices, some of them being plug connected devices. Connecting these devices to a high capacity surge generator left most destroyed. ALL of the cheap M.O.V. plug strip devices I tested were destroyed with little effort, and the devices plugged into the were also destroyed, or damaged. Some of the series mode suppressors I tested were capable of withstanding repeated or continuous high level surges, and in addition protected the devices plugged into them.

I also agree with your portrayal of lightning/surge protection as a system wide approach, and have a good laugh when even technically trained people try to apply protection in a piecemeal manner sometimes without even verifying/examining the remainder of the system that should be considered as well.

If you are bored, and want a real laugh read one of the warrantees that come with many of the ineffectual shunt mode surge suppressors! I doubt that many have collected on these due to the hoops that have to be jumped through. It has also been explained to me that it's a common business practice to place warrantees on surge devices that they know wont provide secure protection, and depend on the fact that most wont go through the bother jumping through the hoops necessary to collect, and pay off those that do considering it a cost of doing business. Kind of like the rebate process on many consumer items.

Louis

Reply to
Louis Bybee

All of the electrodes at any given structure must be bonded to each other. That even applies to lightning grounding electrodes. If you have two or more grounding electrode systems then the voltage difference between the different systems will equalize through the very equipment that you are trying to protect. You will have to bond the new grounding electrode to the electrical grounding electrode system. Remember that the neutral conductor of the service is grounded via the main bonding jumper to the electrical grounding electrode system. So if a lightning event energizes your stand alone ground rod it will equalize through the satellite receiver's and television power cord neutral conductors to the electrical grounding electrode system. If on the other hand you bond the new electrode to the electrical grounding electrode system the voltage on both sides of the receiver will rise and fall in unison as the lightning current dissipates and no destructive current flow will occur.

If what you really want is absolution for doing it wrong then it is your television so do what you please.

-- Tom H D841733 Local 26, IBEW

Reply to
hornetd

Sorry. I guess you will need to get a professional who does understand it to look at your situation and provide on site assistance, since describing it over the internet isn't working for you.

As a Journeyman Electrician, please read article 250-50. It says, in part: "If available on the premises at each building or structure served, each item (a) through (d), and any made electrodes in accordance with Sections 250-52(c) and (d), shall be bonded together to form the grounding electrode system."

If tat reads like tax code to you, it nets out that a proper connection from the new ground rod to the existing grounding electrode system IS required, per the quoted article.

I don't know how they are installing all these dishes. How "they" are doing it is not at issue. What is at issue is how to do it right. There is NO controversy - there are rules that must be followed, per the NEC. At a minimum, those rules must be followed.

Reply to
ehsjr

See that is the thing. The dish comes with a free

Reply to
Kilowatt

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