Using old ground rod

Reply

  #1  
Old 03-11-14, 05:34 PM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
Using old ground rod

Recently got a new service. They drove a new ground rod. The old ground rod is about 2' away from the new one. I want to put a police scanner antenna on the side of the house.... can I use the old ground rod for my antenna? (because of the close proximity I thought I should ask)
 
Sponsored Links
  #2  
Old 03-11-14, 06:47 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 13,057
Received 73 Votes on 65 Posts
I can't think of any reason you can't.
 
  #3  
Old 03-11-14, 07:54 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,996
Received 39 Votes on 34 Posts
It should be bonded to the new rod.
 
  #4  
Old 03-11-14, 07:57 PM
Member
Join Date: Jun 2012
Location: USA
Posts: 1,437
Received 16 Votes on 14 Posts
You can use the old rod but it still should be bonded to the new one.

From NEC:
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.
 
  #5  
Old 03-11-14, 08:52 PM
Member
Join Date: Mar 2010
Location: USA
Posts: 3,757
Received 42 Votes on 40 Posts
The old ground rod may be used for any grounding purpose for which a rod might be used unless you have reason to believe that it is insufficient such as having less than 8 feet of buried length. (Shorter rods standing alone will likely work okay for radio and TV purposes.)

For any single building, all ground rods about it including this old rod, one cold water pipe (if metal) exiting the building underground, and one rebar (if any) in concrete foundation components below grade must be interconnected (bonded together) as part of the grounding electrode system.

This old rod will not qualify as the "second and last" ground rod needed to satisfy the 25 ohm impedance to ground given only the new ground rod because the two are less than 6 feet apart.
 
  #6  
Old 03-12-14, 08:43 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
can I use the old ground rod for my antenna?
It looks to me like the better option would be to terminate the antenna ground to the intersystem grounding bridge that your electrician should have installed at the GEC to the new ground rod. Your antenna is a good example of why the bridge is required by code.
 
  #7  
Old 03-12-14, 12:28 PM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
That was my concern Joe... I wasn't sure it was cool to add things to the ground rod I figured the ground rod was only for the electrical system.

So its safe/ok to add a clamp at the rod, running #6 up to the bridge, I can then put my tv, phone, scanner antenna or anything else that needs grounding there? And if lightning strikes my antenna, then my electrical system is still safe!

Thanks, please clarify if I am not grasping the concept from what I describe....
 
  #8  
Old 03-13-14, 11:15 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
So its safe/ok to add a clamp at the rod, running #6 up to the bridge,
You should already have a #6 going to the ground rod, that's where I'd install the intersystem bridge.
 
  #9  
Old 03-13-14, 11:26 AM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
You should already have a #6 going to the ground rod, that's where I'd install the intersystem bridge.
Its in conduit. Only a little bit of it is exposed right at the ground rod and the bridge I dont think is meant to dangle in mid air... its supposed to be mounted to the siding right?

Did I do something wrong adding the clamp and #6 solid?

This is the one I ended up using....

Intersystem Bonding Termination
 
  #10  
Old 03-13-14, 11:51 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
Its in conduit. Only a little bit of it is exposed right at the ground rod and the bridge I dont think is meant to dangle in mid air... its supposed to be mounted to the siding right?
What kind of conduit; PVC, EMT? Can you provide a picture? My first inclination would be to shorten the conduit, but I'd like to see a picture before recommending that. Yes, the bridge needs to be mounted to the siding.

Did I do something wrong adding the clamp and #6 solid?
I wouldn't do it that way and that's not what the instructions call for. I believe there is a bridge available for when the GEC is in PVC conduit.
 
  #11  
Old 03-13-14, 12:03 PM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
That GEC is in EMT. I don't want to cut it either, this is a new pro install and don't want to hack it up. Also this is bonding termination is not mandatory in our area, we are not on 2008 code cycle. But my stuff does need to get grounded.

The instructions mention that if you cant get on the GEC, its acceptable to ground to the meter enclosure or the metallic raceway....

The phone co. usually just clamps to that raceway. Would it be acceptable then to run a short length of #6 from the raceway to this device which is mounted right next to it?

And since the manufacture says it acceptable to ground to the metallic raceway, what type of clamp is best to use on a 1.5 inch raceway? The poco use a pipe strap with a copper/brass grounding terminal with a nut on it.
 

Last edited by ardmi; 03-13-14 at 12:47 PM.
  #12  
Old 03-13-14, 05:09 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
That GEC is in EMT.
That's a problem unless both ends of the metallic conduit are properly bonded by the GEC with appropriate bonding bushings. That's why the GEC to a ground rod is generally run open and surface mounted and secured with copper plated 1-hole straps OR run in PVC conduit.

And since the manufacture says it acceptable to ground to the metallic raceway, what type of clamp is best to use on a 1.5 inch raceway? The poco use a pipe strap with a copper/brass grounding terminal with a nut on it.
In that case, I'd run it to inside the meter socket and install a grounding lug to the box.
 
  #13  
Old 03-13-14, 05:54 PM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
Maybe you would, but your ok with opening the meter socket... not sure that's DIY friendly for me... lol.

As I describe it though, grounding to the raceway is also acceptable no? And if it is not, please explain.

ps- the conduit is bonded, it passed an inspection.
 
  #14  
Old 03-13-14, 05:59 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
ps- the conduit is bonded, it passed an inspection.
At both ends? This means the open end near thr ground rod too.

As I describe it though, grounding to the raceway is also acceptable no? And if it is not, please explain.
Rather than try to attach to a larger conduit, I think I'd go back to what you first mentioned and run a #6 over to the ground rod. That's my 2nd choice, 1st choice is the ground lug inside the socket.
 
  #15  
Old 03-13-14, 06:23 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,996
Received 39 Votes on 34 Posts
The meter socket should be sealed by the power company. Any additional conductor could be run from the panel to connect the intersystem bond.
 
  #16  
Old 03-14-14, 04:12 AM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
Thanks again!

What about the 1.5" rigid conduit raceway between the socket and the panel. Nobody commented on that. Is that not acceptable or compliant?

The directions for the ICB says that is OK. Also the teleco grounds to that raceway on every installation in our area. (In fact, if you put in an ICB they would still ground to the raceway and ignore the device).

So is there a reason I shouldn't have the ground on the raceway?
 
  #17  
Old 03-14-14, 06:06 AM
Member
Join Date: Mar 2010
Location: USA
Posts: 3,757
Received 42 Votes on 40 Posts
Don't cut any of the existing grounding electrode conductors.

The equipment will be electrically grounded when the ground wire from the equipment is attached (e.g. clamped) to any point on the grounding electrical system for example to one of the ground rods that is already bonded to the electrical system neutral (using a GEC), or to a GEC.

Your newly installed grounding electrode system has to be connected to the system neutral. If you cannot make that connection in the meter box then you must extend additional wire as grounding electrode conductor to the next panel downstream. If you only have #6 existing GEC and you need to add a fatter GEC say from a water pipe or rebar, then the fatter GEC has to continue, perhaps alongside the exisiting GEC, to the system neutral.
 
  #18  
Old 03-14-14, 06:37 AM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
I somewhat understand that... but that is not the protocol of the telephone company. It is acceptable practice to ground their phones to the raceway as I describe and is done that way on all houses here. My area does not have code requirements for the IBD either.

So to confirm, it is alright to ground to the raceway between the meter and the panel? Or is my stuff going to fry?....
 
  #19  
Old 03-14-14, 11:11 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
So to confirm, it is alright to ground to the raceway between the meter and the panel? Or is my stuff going to fry?....
I am not aware of any U.L. Listed clamp for the purpose you are asking, connecting to 1 1/2" conduit.

Also the teleco grounds to that raceway on every installation in our area. (In fact, if you put in an ICB they would still ground to the raceway and ignore the device).
Most telephone companies do not have a reputation for code compliance or even neat workmanlike installations and that's a tricky subject because they are generally considered a regulated utility and not subject to requirements/inspections of the AHJ. In their minds they don't have to comply with any stinkin codes.
 
  #20  
Old 03-14-14, 01:11 PM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
They are called galvanized grounding straps or something similar.... they have a split bolt type connection and are UL listed, they are standard for most catv, sat. and phone installers.


And what is not "neat or workmanlike" about grounding to the raceway if its code compliant?

You mention the Telco doesn't follow the NEC but I don't see what is not compliant in the installation I describe? (Again, we are not on the 2008 code cycle so the intersystem bonding termination is not mandatory)

And about putting it on the raceway in general, nobody commented about that, what is not electrically sound about that?
 
  #21  
Old 03-14-14, 04:00 PM
Banned. Rule And/Or Policy Violation
Join Date: Jul 2009
Location: usa
Posts: 102
Received 0 Votes on 0 Posts
> It is acceptable practice to ground their phones to the raceway as I describe
> and is done that way on all houses here. My area does not have code
> requirements for the IBD either.

Two completely different functions are addressed by earth ground. Code addresses human safety. Therefore code says where an antenna must be earthed, that all earth electrodes must be internconnected, distance that must exist between multiple electrodes, how thick an earth ground wire must be, and even why a telco NID (subscriber interface) must be earthed.

Second function means an earth ground must also exceed code requirements for transistor safety. That means a ground wire from breaker box to earth ground electrode must be as short as possible (ie 'less than 10 feet'), no splices or sharp bends, not inside metaillic conduit, and separated from non-grounding wires. Ground for each incoming utility wire (cable, telephone, satellite dish, AC electric, exterior antenna) must be earthed as short as possible to the same earth ground before entering a building.

For example, a ground wire for a telco NID should be routed separately to earth meeting all other ground wires at the electrode. With no sharp bends. Even a connection to a raceway typically increases impedance; compromises protection.

The original post asked about installing an antenna. This must have a 'short as possible' connection to earth. And its antenna lead must route to the single point earth ground so that (if coax) its shield makes short as possible connection. Code even defines the color and gauge of this connecting hardware - typically 10 or 12 AWG. Not to be confused with another ground wire to that antenna.

Code defines what is miminally acceptable for human safety (and that a water pipe ground is insufficient for earth ground). Additional requirements (as discussed above) must be implemented for transistor safety. Code is about protecting humans; does not care about protecting transistors. Protecting transistors is your concern.
 

Last edited by westom; 03-14-14 at 04:32 PM.
  #22  
Old 03-14-14, 06:54 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
They are called galvanized grounding straps or something similar.... they have a split bolt type connection and are UL listed, they are standard for most catv, sat. and phone installers.
The ones I have seen look more like they were fabricated on site from galvanized pipe strap and short bolt and usually fit loosely around the conduit or pipe. I have never seen a commercial one, but if you'd provide a link I'd like to see one.

And what is not "neat or workmanlike" about grounding to the raceway if its code compliant?
I haven't seen your installation, but as described it didn't sound like a neat installation. I have however seen many a telephone company hack job such as cable running up and over a gabled roof to cross to the other side of a house and cables run through bored holes in concrete block walls with no sleeve.
 
  #23  
Old 03-15-14, 08:35 AM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
Again, nobody addresses the raceway. What is not electrically sound about grounding to the metallic conduit between the meter and the panel? Hasn't this been a code compliant method for ever?


As for the grounding strap, how do they say it these days? Google it.... theres a load of different UL ones available... heres one made by Thomas betts (A name I recokgnize) Thomas & Betts DIRECTV Approved 12" Galvanized Ground Strap
 
  #24  
Old 03-15-14, 01:38 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
Again, nobody addresses the raceway. What is not electrically sound about grounding to the metallic conduit between the meter and the panel? Hasn't this been a code compliant method for ever?
I thought that was what we've been discussing. As far as saying the T&B strap is the proper connection to the rigid conduit, I'll not say so unless there is more documentation. The T&B strap you linked to is for a water pipe. As far as I am concerned, grounding to a 1 1/2" rigid steel conduit is not a normal installation. Someone else might have a different opinion.

Product Description

The Thomas & Betts SC13BZ3 12" Galvanized Ground Strap is used to provide a fixed and permanent connection between a steel water pipe to a copper ground wire.
Thomas & Betts DIRECTV Approved 12" Galvanized Ground Strap
 
  #25  
Old 03-15-14, 02:01 PM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
Heres another UL approved one that says it can go on service masts
Skywalker Signature Series Galvanized Ground Strap 8in UL Listed - Skywalker

As far as I am concerned, grounding to a 1 1/2" rigid steel conduit is not a normal installation. Someone else might have a different opinion.
The phone company and the local ahj certainly do. Does the NEC say you cant do it? I believe the outdated book I have shows that this is acceptable but I am not sure how that has changed in the last decade.... so what is the NEC opinion on this?

What is not electrically sound about it? Surely this is done every day around here it cant be a hazard or safety condition?
 
  #26  
Old 03-15-14, 10:40 PM
Banned. Rule And/Or Policy Violation
Join Date: Jul 2009
Location: usa
Posts: 102
Received 0 Votes on 0 Posts
Are you asking about only meeting code requirements for human safety? Or do you also want transistor safety? I thought that point and what exceeds code requirements was obvious

What is required to protect transistors must exceed what code requires. Code is only minimal requrements. Specifically, what problem or threat is to be addressed?

Just because some technician (electrician) only does what is minimally sufficient does not mean that is acceptable. Remember, they only meet code requirements ... to do what? Is that all you want? Or do you want to earth that antenna so that attached electronics are also safe?
 
  #27  
Old 03-16-14, 07:39 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
The phone company and the local ahj certainly do. Does the NEC say you cant do it? I believe the outdated book I have shows that this is acceptable but I am not sure how that has changed in the last decade.... so what is the NEC opinion on this?

What is not electrically sound about it? Surely this is done every day around here it cant be a hazard or safety condition?
Even some hack jobs are code compliant. Go ahead and do it the way you want, but I wouldn't bless it and wouldn't do it that way on my own home either.
 
  #28  
Old 03-16-14, 08:02 AM
Member
Thread Starter
Join Date: Dec 2013
Posts: 284
Received 0 Votes on 0 Posts
Joe- Not looking for your 'blessing' but I did ask a specific question which you avoided again with your last reply....

what is electrically wrong with grounding to the conduit?

I understand codes are a minimum etc.. transistors vs. human safety... but none of that addresses my question.

And BTW... you cant be calling stuff HACK without actually seeing it or at least telling me why its not electrically sound.
 
  #29  
Old 03-16-14, 08:17 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,280
Received 43 Votes on 35 Posts
what is electrically wrong with grounding to the conduit?
If the clamp provides a solid tight connection it would be electricall sound if the conduit is properly installed and bonded.

you cant be calling stuff HACK without actually seeing it
Sure I can.
 
  #30  
Old 03-16-14, 08:32 AM
Banned. Rule And/Or Policy Violation
Join Date: Jul 2009
Location: usa
Posts: 102
Received 0 Votes on 0 Posts
> what is electrically wrong with grounding to the conduit?

It is low resistance (if conduit is tightly connected together) and can be high impedance. Code is only concerned with resistance. Other grounding functions require low impedance.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: