Grounding - Pole Mount 100 ft away

[TradeViceroy]

Evening:

I'm a little confused on grounding a pole mount that is approximately 100 ft from the house (due to LOS issues). I did some research here on grounding pole mounts, but I'm still uncertain. The cable entry is located on the back of the house which is an additional 25 ft. from the main electrical ground. I have checked out DBSInstall and it seems that my best bet is to use the main house electrical ground.


My questions are:

1. The coax grounding blocks are located at the cable entry point. Will #10 grounding wire from the blocks to the main house ground be enough (approx. 25 ft)? Can the cable be directly buried or will conduit need to be used?

2. Will the messenger (ground wire) in a dual RG-6 setup be satisfactory to ground a dish/pole 100 ft away? Where am I supposed to attach the dish/ pole ground on the cable entry end? I would rather not have to add a second ground rod at the rear of the house if it is not required.

Any help or advice would be appreciated. Thank you!

 

[damaged]

1) 10 AWG ground wire _is_ in accordance with 810.21, the wire can be bare or insulated. As for the conduit, yes use it, or if you don't, you should increase the size to make up for the lack of protection, also, if the conduit is metal:

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.

2) You cannot use a metal rod driven into the earth for grounding of the dish and lead-in cable, unless the metal rod is bonded with a 6 AWG conductor to the building grounding electrode system in accordance with 810.21(J)**.
In addition, the NEC does not allow you to use the local water pipe [810.21(F)(1)(b)].

In addition, the lead-in cable from an "outdoor antenna" must be provided with a listed antenna discharge unit (grounding block) located as near as practicable to the entrance of the conductors to the building [810.20]. The discharge unit must be grounded to an acceptable location in accordance with 810.21(F)(1)(a)* through (f)*, with a 10 AWG copper conductor (bare or insulated) that is run in as straight a line as practicable [810.21(E)] to the electrode.

Caution: If the lead-in from an outdoor antenna is not properly earth grounded, the receiver can be destroyed by voltage surges caused by nearby lightning strikes. If the mast is not properly grounded, the Low Noise Block (LNB), could be destroyed by voltage surges caused by nearby lightning strikes.

* (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.


** (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 arate electrodes are used."

 

[TradeViceroy]

1) 10 AWG ground wire _is_ in accordance with 810.21, the wire can be bare or insulated.

2) You cannot use a metal rod driven into the earth for grounding of the dish and lead-in cable, unless the metal rod is bonded with a 6 AWG conductor to the building grounding electrode system in accordance with 810.21(J)**.
In addition, the NEC does not allow you to use the local water pipe [810.21(F)(1)(b)].

In addition, the lead-in cable from an "outdoor antenna" must be provided with a listed antenna discharge unit (grounding block) located as near as practicable to the entrance of the conductors to the building [810.20]. The discharge unit must be grounded to an acceptable location in accordance with 810.21(F)(1)(a)* through (f)*, with a 10 AWG copper conductor (bare or insulated) that is run in as straight a line as practicable [810.21(E)] to the electrode.

Caution: If the lead-in from an outdoor antenna is not properly earth grounded, the receiver can be destroyed by voltage surges caused by nearby lightning strikes. If the mast is not properly grounded, the Low Noise Block (LNB), could be destroyed by voltage surges caused by nearby lightning strikes.

* (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.


** (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 arate electrodes are used."

Thanks for the reply. I know #6 grounding wire is needed to bond two ground rods. However, I don't think I need an additional ground rod in this case.

I'm still confused as to where I'm supposed to terminate the ground coming from the pole/dish. As I said earlier, the electrical ground is 25 ft from the cable entry point. So far, all I have is two dual grounding blocks (which will be hooked into the main house ground via #10 grounding wire) inside of the entry box.

Thanks.

 

[damaged]

The way I read it, you would terminate it as close as possible to an existing ground on the home. So you have a grounding block on your home for the coax entering, you have to have the mast/poles ground on the same (or close as possible) ground as the coax on that block. The idea is that all grounds must be at the same potential, having one ground (coax going in) at the home, and one ground (the masts ground) 100 feet away (and not bound together properly) is bad news. Basically you want _all_ ground wires to converge at the home as close as possible to the single ground being used on the home for the coax entry ground block, if you use metal conduit for the run(s), it too must be grounded to the same convergences. Also, the ground wire runs MUST be in a straight line, no bends!

 

[TradeViceroy]

So, should I terminate it to the ground block then? I thought I read that wasn't such a smart idea.

 

[damaged]

Well not to the block, but the same ground as the entry block.

Maybe this pic can illustrate better.
http://www.mikeholt.com/htmlnews/grounding/figure1.gif