OTA Antenna grounding questions - AVS Forum
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post #1 of 17 Old 06-20-2012, 04:25 PM - Thread Starter
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Just a few questions....

1) Can you ground the antenna and the mast to the service panel inside the house?
2) Can you ground the antenna and the mast to the "main power panel" (sorry don't know exactly what it is called, the metal box that have a meter next to it) outside the house?
3) If you don't know exactly where is the main grounding electrode (mine is hidden under the basement), then do not drive a new grounding rod because you won't be able to bond them together?
4) Is it true that many DIYer (or even contractor) doesn't really ground them properly?

Thanks in advance.
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post #2 of 17 Old 06-20-2012, 06:08 PM
 
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Never ever ground to the inside panel, or inside water pipe. The antenna once connected to the mast, becomes grounded to the mast. You would run a bonding jumper from the mast to a ground rod, or the mast has to be in the ground past the concrete base, to be considered earth grounded.
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post #3 of 17 Old 06-20-2012, 06:14 PM
 
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810.12 Supports
Outdoor antennas and lead-in conductors shall be securely
supported. The antennas or lead-in conductors shall not be
attached to the electric service mast. They shall not be at-
tached to poles or similar structures carrying open electric
light or power wires or trolley wires of over 250 volts be-
tween conductors. Insulators supporting the antenna con-
ductors shall have sufficient mechanical strength to safely
support the conductors. Lead-in conductors shall be securely
attached to the antennas.

810.13 Avoidance of Contacts with Conductors
of Other Systems
Outdoor antennas and lead-in conductors from an antenna to
a building shall not cross over open conductors of electric
light or power circuits and shall be kept well away from all
such circuits so as to avoid the possibility of accidental con-
tact. Where proximity to open electric light or power service
conductors of less than 250 volts between conductors cannot
be avoided, the installation shall be such as to provide a
clearance of at least 600 mm (2 ft).
Where practicable, antenna conductors shall be installed
so as not to cross under open electric light or power conduc-
tors.

810.21 Bonding Conductors and Grounding
Electrode Conductors — Receiving Stations
Bonding conductors or grounding electrode conductors shall
comply with 810.21(A) through (K).
(A) Material. The bonding conductor or grounding elec-
trode conductor shall be of copper, aluminum, copper-clad
steel, bronze, or similar corrosion-resistant material. Alumi-
num or copper-clad aluminum bonding conductors or
grounding electrode 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 conductors shall not be installed
within 450 mm (18 in.) of the earth.
(B) Insulation. Insulation on bonding conductors or
grounding electrode conductors shall not be required.
(C) Supports. The bonding conductors and grounding
electrode 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 bonding conductors and grounding electrode
conductors shall be increased proportionately.

(2) In Buildings or Structures with Grounding Means. If
the building or structure served has no intersystem bonding
termination, the bonding conductor or grounding electrode
conductor shall be connected to the nearest accessible loca-
tion on the following:
(1) The building or structure grounding electrode system as
covered in 250.50
(2) 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
For more information on the use of a metal water piping sys-
tem, see the commentary following 250.52(A)(1).
(3) The power service accessible means external to the
building, as covered in 250.94
(4) The nonflexible metallic power service raceway
(5) The service equipment enclosure, or
(6) The grounding electrode conductor or the grounding
electrode conductor metal enclosures of the power ser-
vice
A bonding device intended to provide a termination
point for the bonding conductor (intersystem bonding) shall
not interfere with the opening of an equipment enclosure. A
bonding device shall be mounted on non-removable parts. A
bonding device shall not be mounted on a door or cover even
if the door or cover is non-removable.

(H) Size. The bonding conductor or grounding electrode
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 bonding conductor or
grounding electrode 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 struc-
ture served where separate electrodes are used.
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post #4 of 17 Old 06-20-2012, 07:25 PM
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Quote:
Originally Posted by gregzoll View Post

Never ever ground to the inside panel, or inside water pipe. The antenna once connected to the mast, becomes grounded to the mast. You would run a bonding jumper from the mast to a ground rod, or the mast has to be in the ground past the concrete base, to be considered earth grounded.

You'd do best to simply quote the relevant NEC sections instead of trying to interpret or condense it since it appears you don't understand it...
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post #5 of 17 Old 06-20-2012, 07:39 PM
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Quote:
Originally Posted by elty View Post

4) Is it true that many DIYer (or even contractor) doesn't really ground them properly?
Yes.
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post #6 of 17 Old 06-20-2012, 07:45 PM
 
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Quote:
Originally Posted by ProjectSHO89 View Post

Quote:
Originally Posted by gregzoll View Post

Never ever ground to the inside panel, or inside water pipe. The antenna once connected to the mast, becomes grounded to the mast. You would run a bonding jumper from the mast to a ground rod, or the mast has to be in the ground past the concrete base, to be considered earth grounded.

You'd do best to simply quote the relevant NEC sections instead of trying to interpret or condense it since it appears you don't understand it...
I probably understand the sections I posted better than you. I have dealt with Section 800 for over 35+ years. You can think that how someone posts something is condescending, but you have to look at it from someone that has dealt with this stuff in the Military, and also does it as a consultant for people, especially when it comes to running networks between buildings, that have to be wired.

Again, may want to go back and read through if you wish the section that I posted, which is relevant to what the person asked about. And the point I made about not connecting to the panel ground bus bar is not the correct way to do this. There is a reason why in commercial installations, that you have a grounding bus for communications to connect to. That bus may be a Ufer ground, or with a run of stranded copper to a main grounding bond point, outside of the structure, depending on the size of the structure.

If the building is set up properly, it should have a bus connection outside for all communication systems to ground to for static discharge, but for grounding an antenna & mast, if it is near the earth bond ground for the structure, you ground there. Otherwise, you have to bond the ground per the appropiate section in the NEC regarding that matter.
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post #7 of 17 Old 06-21-2012, 04:17 AM
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I probably understand the sections I posted better than you.

Probably, because you're not sure. You make many condescending posts, and many of them are fraught with incorrect information. The biggest problem is that you refuse to learn when you are corrected.
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post #8 of 17 Old 06-21-2012, 01:37 PM - Thread Starter
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Actually I have read the relevant section. I guess the thing I don't understand is "service equipment enclosure". Does it mean the panel inside the house, the panel (where the meter is) outside the house, or something completely not related?

Also, is it a bad idea to join 2 grounding wire together (so like forming a Y connection to a ground)? From what I read it seems to be not allowed, but it was not really explained why other than "code said no".
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post #9 of 17 Old 06-21-2012, 01:40 PM
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Quote:
Originally Posted by gregzoll View Post

...but you have to look at it from someone that has dealt with this stuff in the Military...
Reminds me of an old quote: "There is the right way, the wrong way, and the army way." Sorry, couldn't resist.
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post #10 of 17 Old 06-21-2012, 01:56 PM
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Quote:
Originally Posted by elty View Post

...I don't understand is "service equipment enclosure".
Understandable. NEC was not written to be a tutorial, but rather a model legal code. Service equipment is the switches, fuses, breakers, etc. connected to the load end of the service conductors (the utility company drop) , used to disconnect your house from the power grid. So, in most houses, the service equipment enclosure will be where the main breaker or main fuses reside.
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post #11 of 17 Old 06-21-2012, 02:10 PM - Thread Starter
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Quote:
Originally Posted by Colm View Post

Understandable. NEC was not written to be a tutorial, but rather a model legal code. Service equipment is the switches, fuses, breakers, etc. connected to the load end of the service conductors, used to disconnect your house from the power grid. So, in most houses, the service equipment enclosure will be where the main breaker or main fuses reside.

I saw the cable and phone company ground their wire outside the house to the box there, so I guess that is the "service panel enclosure" I am looking for?

Also, side question - is it common to have a service panel to have 2 grounding wire? I just notice my service panel has 2 non insulated copper wire - one leads to a water pipe, the other leads into the basement ground (presumably something is hidden down there).
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post #12 of 17 Old 06-21-2012, 02:58 PM
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Quote:
Originally Posted by elty View Post

I saw the cable and phone company ground their wire outside the house to the box there, so I guess that is the "service panel enclosure" I am looking for?
Only if that is the location of the main breaker or main fuses, or a disconnect switch. If it is only a meter, then no.
Quote:
is it common to have a service panel to have 2 grounding wire? I just notice my service panel has 2 non insulated copper wire - one leads to a water pipe, the other leads into the basement ground...
Yes.
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post #13 of 17 Old 06-21-2012, 03:58 PM
 
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Quote:
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Quote:
Originally Posted by Colm View Post

Understandable. NEC was not written to be a tutorial, but rather a model legal code. Service equipment is the switches, fuses, breakers, etc. connected to the load end of the service conductors, used to disconnect your house from the power grid. So, in most houses, the service equipment enclosure will be where the main breaker or main fuses reside.

I saw the cable and phone company ground their wire outside the house to the box there, so I guess that is the "service panel enclosure" I am looking for?

Also, side question - is it common to have a service panel to have 2 grounding wire? I just notice my service panel has 2 non insulated copper wire - one leads to a water pipe, the other leads into the basement ground (presumably something is hidden down there).
The telco & catv should run to the ground rod outside, if avail. If not, then it should be a common wire to ground to a cold water pipe, that is a not connected to pvc, or something that will break the bond with earth, once it exits the structure.

I ended up moving my NID & catv to the back of the house, so that it was nearer to where my network rack is inside the basement, and I could also ground them to a common block, so that they would be grounded to the earth ground, which the meter pan is also grounded to. I just ended up using some #6 solid that I had laying around, from when we rewired the house a few years back. Between the NID & CATV ground block is a run of #10, that also on the catv is a Gas Discharge, to further protect the incoming catv line.

The way that the 2011 NEC states, is any/all communications, including OTA needs to all connect to a common grounding point, that the ground can be connected to either earth bond, or cold water pipe, with earth ground or Ufer being the best.
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post #14 of 17 Old 06-21-2012, 05:11 PM
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Uh, which is it?
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Originally Posted by gregzoll View Post

Never ever ground to...inside water pipe..
Quote:
the bonding conductor or grounding electrode
conductor shall be connected to the nearest accessible loca-
tion on the following:...
(2) The grounded interior metal water piping systems...
Quote:
...ground to a cold water pipe...
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post #15 of 17 Old 06-21-2012, 06:02 PM
 
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It depends on the situation, but if you can, you always bond to earth ground over water pipes. Electrical strikes have been known after time, to cause pinhole leaks in copper pipes. Plus, with the use of PEX becoming more common place, both outside of the house, and within, you should always bond to earth ground rod. Not the outside of the meter pan, not a faucet you see on the side of the house, not a piece of conduit, but on the ground rod itself, that the meter pan and power panel grounds to.
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post #16 of 17 Old 07-04-2012, 09:56 AM - Thread Starter
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What will happen if you install a separate ground rod, but do not bond it to any nearby existing ground? (other than "the code doesn't allow this")

Is it because if say you stand in between those 2 ground rods, then when something hits rod A the electricity will travel to rod B since they are nearby and hit you in the process?
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post #17 of 17 Old 07-04-2012, 10:38 AM
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What will happen if you install a separate ground rod, but do not bond it to any nearby existing ground?
You will have a difference in ground potential, which can be a safety issue and one reason that NEC requires bonding of ground rods. There is also the issue that the earth is not a particularly good conductor and generally won't carry enough current to clear a fault (trip a breaker).
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