NEC 820-40

The satellite guys say that because they have connected their ground wire
into the AC disconnect that they are grounded according to NEC. I say they
have to drive a 8' ground rod and bond this to the service. I don't have a
code book and every article I have found is not really clear how this is
done.
Anyone want to comment?
Reply to
Kilowatt
Loading thread data ...
From what I read I believe you already have a grounding electrode for you home right? If they carried a #14 or larger ground wire out to the dish and connected that ground wire in your service I think you covered.
An additional ground rod is a messy business.
Reply to
SQLit
Isn't the key connecting it to the service? They have an insulated 8 stranded draped over the side of the house swinging and then striped and rapped around the lock hole in the AC disconnect.
They should either drive a ground rod below the dish or run the conductor to the service panel. Right?
Reply to
Kilowatt
There isn't a lot of information given here, but I suspect the "satellite guys" may not be licensed or even qualified to be engaged in electrical work. At best I envision them having low voltage qualifications which isn't a bad thing, but it might be informative to ask what license they possess.
It would be interesting to know if the disconnect they connected the ground wire to serves the dish, or how they terminated the ground wire its self.
With the limited information supplied it's difficult to armchair the work of the dish installers, but I doubt a ground rod would be required for this installation. Installing a ground rod isn't a problem, and the addition to the grounding electrode system would be a good thing, just not necessarily required. If a ground rod is installed for the dish system it will need to be properly connected or bonded to the existing grounding electrode system/electrical system ground with a minimum #6 Cu conductor in an approved manner.
If you call the electrical inspector having jurisdiction for your area they are usually very helpful, and willing to discuss situations such as this with you. You've cited NEC Article 820, but that is normally applied to CATV systems. I would expect that the inspector would look to article 810 if your installation is serving a single occupancy structure. If the work by the dish vendor isn't suitable the inspector would also be able to address that. It might be helpful to review article 810 before calling the inspector.
If this dish is on the roof it is likely one of the higher metallic elements of the structure, and might present concern as a target for a lighting strike. You might consider having the installation evaluated by someone versed in electrical grounding/bonding, and lightning mitigation if your area has a history of electrical storm activity.
Louis-- ********************************************* Remove the two fish in address to respond
Reply to
Louis Bybee
820.40 Cable Grounding. Where required by 820.33, the shield of the coaxial cable shall be grounded as specified in 820.40(A) through (D). (A) Grounding Conductor. (1) Insulation. The grounding conductor shall be insulated and shall be listed as suitable for the purpose. (2) Material. The grounding conductor shall be copper or other corrosion-resistant conductive material, stranded or solid. (3) Size. The grounding conductor shall not be smaller than 14 AWG. It shall have a current-carrying capacity approximately equal to that of the outer conductor of the coaxial cable. The grounding conductor shall not be required to exceed 6 AWG. (4) Length. The grounding conductor shall be as short as practicable. In one- and two-family dwellings, the grounding conductor shall be as short as practicable, not to exceed 6.0 m (20 ft) in length. Exception: In one- and two-family dwellings where it is not practicable to achieve an overall maximum grounding conductor length of 6.0 m (20 ft), a separate ground as specified in 250.52(A)(5), (6), or (7) shall be used, the grounding conductor shall be grounded to the separate ground in accordance with 250.70, and the separate ground bonded to the power grounding electrode system in accordance with 820.40(D). (5) Run in Straight Line. The grounding conductor shall be run to the grounding electrode in as straight a line as practicable. (6) Physical Protection. Where subject to physical damage, the grounding conductor shall be adequately protected. Where the grounding conductor is run in a metal raceway, both ends of the raceway shall be bonded to the grounding conductor or the same terminal or electrode to which the grounding conductor is connected. (B) Electrode. The grounding conductor shall be connected in accordance with 820.40(B)(1) and (B)(2). (1) In Buildings or Structures with Grounding Means. To the nearest accessible location on the following: (1) The building or structure grounding electrode system as covered in 250.50; (2) The grounded interior metal water piping system, within 1.52 m (5 ft) from its point of entrance to the building, as covered in 250.52; (3) The power service accessible means external to enclosures as covered in 250.94; (4) The metallic power service raceway; (5) The service equipment enclosure; (6) The grounding electrode conductor or the grounding electrode conductor metal enclosure; or (7) The grounding conductor or the grounding electrode of a building or structure disconnecting means that is grounded to an electrode as covered in 250.32. (2) In Buildings or Structures Without Grounding Means. If the building or structure served has no grounding means, as described in 820.40(B)(1): (1) To any one of the individual electrodes described in 250.52(A)(1), (2), (3), (4); or, (2) If the building or structure served has no grounding means, as described in 820.40(B)(1) or (B)(2)(1), to an effectively grounded metal structure or to any one of the individual electrodes described in 250.52(A)(5), (6), and (7). (C) Electrode Connection. Connections to grounding electrodes shall comply with 250.70. (D) Bonding of Electrodes. A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected between the antenna systems grounding electrode and the power grounding electrode system at the building or structure served where separate electrodes are used. Exception: At mobile homes as covered in 820.42. FPN No. 1: See 250.60 for use of air terminals (lightning rods). FPN No. 2: Bonding together of all separate electrodes limits potential differences between them and between their associated wiring systems.
Reply to
Gerald Newton
I'm confused, are they runnig 120V out to the dish or just the ground wire?. Is the discconect for the dish or just somthing convient. Is the dish metal.? Maybe this wire is a lighting ground (a different issue).
Reply to
deanmk
What should the installer do to ground the dish properly? My sister had 2 tvs struck by lightning before she found out her dish was not grounded (at all) properly. She said they came out and drove a ground rod at the dish and bonded it there. No connection was made to the house. She hasn't been hit again but the ground rod at the dish is ok?
Reply to
Kilowatt
Ok. I saw all that but I am still unsure what the guy should do to attach the dish ground to my house.
Does this mean that he should run a wire through the attic and open my service panel and attach there? Can he go in the basement and bond to any water pipe? Is the connection he made to my AC disconnect considered connected to be grounded?
I really don't want lightning to fry my TV.
Reply to
Kilowatt
The AC is just something convent for a ground, I guess. They told me that the 3 prong plug is what they are using for the ground. I told them that because my sister lost 2 tvs to lightning that the 3 prong plug won't fly. I really don't know what they should but I know that the 3 prong plug didn't protect my sister's tv.
Reply to
Kilowatt
Your grounding electrode conductor and main bonding jumper should be in the service disconnect enclosure. That is exactly where the bonding to the satellite should go It just needs to be brought inside the enclosure to the ground bus bar.
Reply to
Greg
Just read the section - it answers all your questions. Basically, you run a No.14 to the service if it is not more than 20 feet away or you install a separate grounding electrode. The no. 14 is bonded to the service disconnect on the outside using a small split bolt stud. If you think the No. 14 is subject to damage use a No. 6 or even a No. 4 solid copper and staple along the way. You can use a separate ground rod , but if it is less than 20 feet from the service ground rod they must be bonded together. I would do this using a direct buried No. 6 solid copper bonding jumper. This is not the least expensive way nor is it required. But remember the NEC is a minimum safety standard. There is no problem in being better than the NEC.
Reply to
Gerald Newton
This definitely is not to Code! Most dish people do not know the frist thing about grounding. Call your local inspector or get an electrician to do it right.
Reply to
Gerald Newton
In a new installation the electrician would have had to install one of the means in 250.94 of the US NEC to provide a place to bond other systems such as your receiving station antenna. That is what it is by the way rather than a cable television system. The US NEC allows the grounding conductor to run inside or outside but it must connect to the service equipment, electrical service Grounding Electrode Conductor (GEC), an electrical service grounding electrode, the accessible means covered in 250.94, or to a separate grounding electrode that is then bonded to the electrical service grounding electrode system. The sections that would seem to apply are quoted below. Attaching the grounding conductor to the Air Conditioning disconnect is not an acceptable method of grounding the antenna structure or the discharge unit for the lead in. -- Tom H
"250.94 Bonding for Other Systems. An accessible means external to enclosures for connecting intersystem bonding and grounding conductors shall be provided at the service equipment and at the disconnecting means for any additional buildings or structures by at least one of the following means: (1) Exposed nonflexible metallic raceways (2) Exposed grounding electrode conductor (3) Approved means for the external connection of a copper or other corrosion-resistant bonding or grounding conductor to the grounded raceway or equipment."
"810.15 Grounding. Masts and metal structures supporting antennas shall be grounded in accordance with 810.21.
810.21 Grounding Conductors -- Receiving Stations. Grounding conductors shall comply with 810.21(A) through (J). (A) Material. The grounding conductor shall be of copper, aluminum, copper-clad steel, bronze, or similar corrosion-resistant material. Aluminum or copper-clad aluminum grounding conductors shall not be used where in direct contact with masonry or the earth or where subject to corrosive conditions. Where used outside, aluminum or copper-clad aluminum shall not be installed within 450 mm (18 in.) of the earth. (B) Insulation. Insulation on grounding conductors shall not be required. (C) Supports. The grounding conductors shall be securely fastened in place and shall be permitted to be directly attached to the surface wired over without the use of insulating supports. Exception: Where proper support cannot be provided, the size of the grounding conductors shall be increased proportionately. (D) Mechanical Protection. The grounding conductor shall be protected where exposed to physical damage, or the size of the grounding conductors shall be increased proportionately to compensate for the lack of protection. Where the grounding conductor is run in a metal raceway, both ends of the raceway shall be bonded to the grounding conductor or to the same terminal or electrode to which the grounding conductor is connected. (E) Run in Straight Line. The grounding conductor for an antenna mast or antenna discharge unit shall be run in as straight a line as practicable from the mast or discharge unit to the grounding electrode. (F) Electrode. The grounding conductor shall be connected as follows: (1) To the nearest accessible location on the following: a. The building or structure grounding electrode system as covered in 250.50 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 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 (G) Inside or Outside Building. The grounding conductor shall be permitted to be run either inside or outside the building. (H) Size. The grounding conductor shall not be smaller than 10 AWG copper, 8 AWG aluminum, or 17 AWG copper-clad steel or bronze. (I) Common Ground. A single grounding conductor shall be permitted for both protective and operating purposes. (J) Bonding of Electrodes. A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected between the radio and television equipment grounding electrode and the power grounding electrode system at the building or structure served where separate electrodes are used." Copyright 2002 National Fire Protection Association.
Reply to
Tom Horne
As I indicated in my previous post, I doubt that the dish installers have the expertise to address the grounding/bonding as evidenced by the manner of their work so far.
If I were in your shoes I would do the following (as I suggested earlier) in the following order:
1) Read article 810 of the NEC, and then call your local electrical inspector asking for an evaluation of the work so far.
2) Contact an electrician, or other qualified electrical professional to advise/correctly complete the installation.
3) Although the NEC allows the Grounding Wire to be run inside/outside the structure, I would run it, and the Bonding of Electrode where required, from the dish outside the structure as straight as possible directly to the ground. From there direct buried to the service location. It isn't necessary to enter the service equipment to make the connection, but is one of the permissible methods. If present I would connect to the Grounding Electrode Conductor outside the building with an exothermic, or other approved method. You could drive a ground rod and bond it as well, but I believe the direct buried conductor would be far more effective than a driven ground rod. Running the grounding/bonding conductor inside the home before connecting to the electrical system grounding grid is asking for trouble in an area where lightning activity is likely.
Louis
Reply to
Louis Bybee
If the installation does not meet NEC requirements (as others have suggested), then installer can be held accountable to repair an installation at his cost. But NEC only addresses human safety issues. You are concerned also about transistor safety - from lightning. Why was your sister's TV damaged? Lightning sought earth ground. Best path to earth was through her TVs.
I must make assumptions about your installation. For example, dish is atop the roof. For lightning protection, a direct ground wire from dish is earth ground rod is necessary - as if the dish were a lightning rod. Lightning seeking the electrically best path into earth would prefer a shorter path (assuming well earthed ground rod) rather than the longer path via TVs.
Coax is more than 20 feet down from roof. Therefore the coax must route to and enter building at service entrance so that coax grounding block (available everywhere from Home Depot to Radio Shack) makes a less than 10 foot connect to AC electric and telephone earth ground rod - the building's central earth ground. This connection serves two masters. First, meets NEC requirements for human safety. Second, earths incoming transients before getting near to TV.
Think of the installation as if it were two structures. One is your building; other is the dish. Each therefore must have its own central earth ground. That short 14 AWG (or larger) ground wire from dish to dedicated ground rod would be the dish's connection to its central earth ground. Same concept is demonstrated in this figure where building and tower are each earthed as if separate structures:
formatting link
Notice that both central earth grounds are connected. That makes the earthing system that much more effective. Dish's ground rod connected to building's ground by a buried, bare copper wire. How good does you earthing system need be? A function defined by neighborhood experience and geological conditions. But protection is defined by what people forget because they don't see it - the earthing system. Interconnecting those ground rods by a buried copper wire can only enhance the earthing system significantly - if neighborhood history recommends it.
NEC requires telephone and cable to connect less than 20 feet to the same AC electric earth ground. That for human safety. You want to exceed NEC requirements to protect transistors. Therefore connections to a central earth ground (by hardwire or via surge protector) must be less than 10 feet. Not ten feet to main disconnect. Ten feet to main disconnect AND additional feet to earth ground. That earth ground (and connections to it) determines probability of lightning damage.
Recently had a long discussion with two CATV installers. As I explained this, the installer was having revelations. They had 'sort of' taught him this, but it was not understood. For example, he was running a CATV wire directly into second floor TV. Wrong. First the CATV wire must drop down to central earth ground so that earthing connection (from ground block to earthing rod) is less than 10 foot. Only then does CATV wire rise back up to enter second floor. Furthermore, the dropping CATV wire must be separated from the rising wire - so as to not induce transients on wire after ground connection. He was installing CATV wire correctly according to NEC requirements - a 20 foot connection to earth. But for transient protection, cable must first drop to make an earth ground connection.
They connected your dish to some earth ground? Some installers connect to a water faucet. Look at that connection. How many feet from faucet to earth ground? That length increases with each copper pipe solder joint and each 90 degree bend. IOW that faucet connection is not an earth ground from the perspective of transients. And it is no longer acceptable as an earth ground from perspective of NEC. That third prong on an AC electric plug is also not an earth ground - for same reasons. And yet many cable installers will deny this. All utilities (including dish cable) should enter building at a common service entrance so that all can be earthed, less than 10 foot, to a single point earth ground. Those are the concepts. Hope they are appropriate for your solution.
Kilowatt wrote:
Reply to
w_tom
For some arbitrary reason, manufacturer decided to change this URL:
formatting link
w_tom wrote:
Reply to
w_tom

Site Timeline

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.