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Old 12-31-2011, 11:59 AM   #1
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Separate ground rod for coax splitter?


Hi all,
My service panel has a new ground rod located right next to the panel. It uses 4 gauge wire (100a panel). I installed the new rod because I thought the existing rod was too far away from the panel (about 40').

My question has to do with a coax splitter where the line comes in from the pole into my house, and is split to the modem & cable box. There is a ground screw on the splitter, so it appears it is designed to take a ground wire. The splitter & coax service line is located about 25' from the main service panel and new ground rod.

The old ground rod is about 15' from the splitter.

I've read that you should never use two ground rods, but would this include having the panel on one rod, and the splitter on a different rod? Or should I just run a 25' section of copper grounding wire and tie into the service panel grounding rod?

Thanks in advance.

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Old 12-31-2011, 12:09 PM   #2
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Separate ground rod for coax splitter?


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Originally Posted by sheslostcontrol View Post
Separate ground rod for coax splitter?
Attach the splitter to the bare ground wire (#12 is OK)...
or to the old rod if that is closer.

Quote:
I've read that you should never use two ground rods...
You read wrong. There are all sorts of reasons to use two rods.
Some are even good reasons.

BTW... if you get a wild hair and feel compelled to run a wire between the two ground rods you have... don't use anything less than a #6 wire.

hth


Last edited by TarheelTerp; 12-31-2011 at 12:15 PM.
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Old 12-31-2011, 12:16 PM   #3
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Separate ground rod for coax splitter?


Quote:
Originally Posted by sheslostcontrol

I've read that you should never use two ground rods

Thanks in advance.
Thats not true you can use as many ground rods as you want
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Old 12-31-2011, 12:24 PM   #4
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Separate ground rod for coax splitter?


The two rods do need to be connected together.
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Old 12-31-2011, 12:34 PM   #5
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Separate ground rod for coax splitter?


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Originally Posted by TarheelTerp View Post
BTW... if you get a wild hair and feel compelled to run a wire between the two ground rods you have... don't use anything less than a #6 wire.
Hopefully he does, because it's required. No matter how many ground rods are installed (and usually two are required), they all MUST be connected together and bonded to the system neutral conductor.

Installing extra ground rods and connecting things to them without bonding them to the system is not code compliant, and can be more dangerous than having no ground rod under certain fault conditions.
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Old 12-31-2011, 12:50 PM   #6
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Separate ground rod for coax splitter?


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Hopefully he does, because it's required.
That is plainly untrue. I get your point but it's too simplistic.
There are millions of old services functioning perfectly well without the second rod.

Some jurisdictions (and contractors) have gotten into the practice of accepting two rods rather than going through the trouble of testing the impedance or resistance with one rod... and/or the metal water pipe issues etc (250.53, .56) (Not that the second rod does anything wrt improving inadequate impedance.

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No matter how many ground rods are installed (and usually two are required), they all MUST be connected together and bonded to the system neutral conductor.
Er no, not quite. More than two is never required...
but on jobs where the second rod is called for.... is it ever set 40 feet apart from the first? No.

Last edited by TarheelTerp; 12-31-2011 at 01:00 PM.
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Old 12-31-2011, 12:55 PM   #7
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Separate ground rod for coax splitter?


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Originally Posted by sheslostcontrol View Post
Hi all,
My question has to do with a coax splitter where the line comes in from the pole into my house, and is split to the modem & cable box. There is a ground screw on the splitter, so it appears it is designed to take a ground wire. The splitter & coax service line is located about 25' from the main service panel and new ground rod.

The old ground rod is about 15' from the splitter.
I'm a belt-and-suspenders kind of a guy. I would bond old rod to new with 4 ga. copper or better, and bond the splitter to the old one with 8 ga. copper. (IIRC: NEC requires either 8 ga. aluminum or 10 ga. copper for antenna grounding. So I go it one better and use 8 ga. copper.)

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Originally Posted by sheslostcontrol View Post
I've read that you should never use two ground rods, but would this include having the panel on one rod, and the splitter on a different rod?
Yes. Two separate grounding systems is regarded as a Bad Thing, by many. (May even be against code? Dunno.) Two reasons: 1. Not all grounds are created equal. You can actually get voltage differentials between different grounds, and 2. If your service ground degrades, then the path to the other ground may see current flow for which it's not designed.

I figure bonding them, as I would do, makes both those problems go away.

Properly bonded together: More ground rods are better than fewer. (Assuming they're all effective, which, depending upon a variety of factors, isn't necessarily a given.)

Jim
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Old 12-31-2011, 01:22 PM   #8
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Separate ground rod for coax splitter?


Article 250 of the NEC clearly requires any and all grounding electrodes to be bonded together. If there are 2 rods they need to be connected together. You cannot use one for the service and one for the cable and/or phone.
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Old 12-31-2011, 01:35 PM   #9
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Separate ground rod for coax splitter?


Does nec require grounding coax?
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Old 12-31-2011, 01:41 PM   #10
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Separate ground rod for coax splitter?


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Does nec require grounding coax?
Clarify, please. "Coax" can mean anything from cable TV, to outside antenna, to the coax used to connect together various home theater components.

That last instance (HT components): No. Outside antenna: Definitely yes, along with a lightning arrestor. Cable TV: I honestly do not know. (My cable company installer did, however.)

Jim
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Old 12-31-2011, 01:47 PM   #11
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Separate ground rod for coax splitter?


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Article 250 of the NEC clearly requires any and all grounding electrodes to be bonded together. If there are 2 rods they need to be connected together. You cannot use one for the service and one for the cable and/or phone.
This opens another can of worms. Fixing the original issue by tying old and new rods together with #4 copper is easy enough (except for the cost of the wire ugh).

I have a detached garage with its own service panel and separate power feed from the street. It has its own ground rod and was originally not connected with the house in any way. Then I wanted to extend coax, cat5 and security system wiring to the detached garage, which I did using appropriate underground cable and 4" bury-able conduit.

Sounds like I have a new problem I didn't see before. That coax & ethernet wire creates a path for electricity to follow, if things were to degrade with the right conditions.

Pulling #4 copper wire through 50' of conduit with two 45s is going to be pure hell. That is if I don't damage the existing wiring (one of the security feeds is 24 gauge).

Is it OK to bury ground wire direct in the dirt (between the house & garage), or does that negate the purpose of having a single ground rod?

Last edited by sheslostcontrol; 12-31-2011 at 01:52 PM.
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Old 12-31-2011, 01:53 PM   #12
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Separate ground rod for coax splitter?


Quote:
Originally Posted by More Power!
Clarify, please. "Coax" can mean anything from cable TV, to outside antenna, to the coax used to connect together various home theater components.

That last instance (HT components): No. Outside antenna: Definitely yes, along with a lightning arrestor. Cable TV: I honestly do not know. (My cable company installer did, however.)

Jim
Well what I was trying to get at is assuming what the OP wants to ground is not regulated by the nec, then he can connect it to a separate grounding rod.
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Old 12-31-2011, 02:03 PM   #13
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Separate ground rod for coax splitter?


You should not have both 120/240 and security wiring in the same conduit.

The grounding conductor does not have to be solid. In fact larger than #8 is stranded anyway. The bare or green solid is used outside of a conduit due to its lack of flexibility.
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Old 12-31-2011, 02:16 PM   #14
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Separate ground rod for coax splitter?


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Well what I was trying to get at is assuming what the OP wants to ground is not regulated by the nec, then he can connect it to a separate grounding rod.
No, he cannot. The shield from that coax is going to be connected to the chassis ground on the cable modem and converter boxes, thus to ground (and most likely neutral, btw) on the inside wiring. This is precisely the problem that the NEC seeks to address by prohibiting separate grounding systems.

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Old 12-31-2011, 02:24 PM   #15
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Separate ground rod for coax splitter?


Quote:
Originally Posted by More Power!
No, he cannot. The shield from that coax is going to be connected to the chassis ground on the cable modem and converter boxes, thus to ground (and most likely neutral, btw) on the inside wiring. This is precisely the problem that the NEC seeks to address by prohibiting separate grounding systems.

Jim
Ok I'll take your word for it cuz its out of my field

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