Grounding Rod to Grounding Electrode System

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  #1  
Old 11-13-14, 11:19 AM
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Grounding Rod to Grounding Electrode System

I'm trying to install an outdoor antenna at my parent's house and was wondering how to connect the wire that goes to the grounding rod to the grounding electrode system through the service panel when there doesn't appear to be a grounding bus bar in the service panel.

Here's the inside:

 
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  #2  
Old 11-13-14, 11:52 AM
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Main panels (the first disconnect after the meter) have neutrals and grounds connected together. After this point in the system, neutrals and grounds must remain separated.

So you would tie your ground wire from the antenna to the bar at the top left. Might be a bit easier said than done as it's a bit inaccessible and looks like it's already pretty full. Technically, each neutral wire needs its own screw while grounds can often share 2 or 3 under one screw.
 
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Old 11-13-14, 06:25 PM
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Rather than install a ground from the antenna into the panel, I would just install an intersystem bonding bar outside above the ground rod and install my antenna ground wire there. Much easier and you won'r have to enter the main panel at all.

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  #4  
Old 11-14-14, 03:42 AM
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Just a question; why are the two 2 pole breakers at the top left jumpered together?
 
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Old 11-14-14, 05:48 AM
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...why are the two 2 pole breakers at the top left jumpered together?
Good catch! I'm pretty sure that Cutler-Hammer circuit breakers are not listed for more than one conductor but even if I am wrong on that point I know of NO residential situation that would allow for paralleled circuit breakers.
 
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Old 11-14-14, 06:38 AM
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Main panels (the first disconnect after the meter) have neutrals and grounds connected together. After this point in the system, neutrals and grounds must remain separated.

So you would tie your ground wire from the antenna to the bar at the top left. Might be a bit easier said than done as it's a bit inaccessible and looks like it's already pretty full. Technically, each neutral wire needs its own screw while grounds can often share 2 or 3 under one screw.

So would it be better to just mount a GBK10P grounding bar at the bottom below the breakers and bond the two by placing a wire in one of the screws on the top left bus bar to a screw on the additional grounding bar, and then adding a few of the ground wires and the wire coming from the grounding rod to it?
 
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Old 11-14-14, 07:08 AM
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Rather than install a ground from the antenna into the panel, I would just install an intersystem bonding bar outside above the ground rod and install my antenna ground wire there. Much easier and you won'r have to enter the main panel at all.
Actually, the grounding wire from the antenna will be going to the grounding rod. What I'm trying to do is connect the grounding rod to the grounding electrode system as required by the NEC. However, my parent's house was built in 1929 and there doesn't appear to be a local electrical ground. Instead it appears to be relying on the incoming neutral wire from the electrical service.
 
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Old 11-14-14, 07:21 AM
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There should be a ground rod or a water line ground at the house.
 
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Old 11-14-14, 07:26 AM
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If you have city water, the grounding electrode is probably the incoming copper water pipe. It won't hurt to add some additional rod(s) as well and make sure everything is all bonded together well.

Exiting the main panel it looks like the rigid metal conduit may be used as the ground due to the bonding bushing on the lower right of the picture.
 
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Old 11-14-14, 07:36 AM
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why are the two 2 pole breakers at the top left jumpered together?
I am wondering if that might be an old split bus panel. Someone could have double lugged off the lighting Main.
 
  #11  
Old 11-14-14, 08:01 AM
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If you have a metal cold water pipe exiting the house undeground then that must be one of the grounding electrodes. The grounding electrode conductor is typically #4 copper but under some circumstances may be different; I don't have the table of sizes in front of me.

If you have a ground rod used for any purpose then that must be one of the grounding electrodes, connected to the rest of the grounding electrode system by a #6 copper wire.

A properly installed rigid metal conduit may be used as the equipment grounding conductor for the circuit(s) whose conductors are carried within but may not serve as part of the run of a grounding electrode conductor on the way to a ground rod, etc.
 

Last edited by AllanJ; 11-14-14 at 08:19 AM.
  #12  
Old 11-14-14, 09:05 AM
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why are the two 2 pole breakers at the top left jumpered together?
I am wondering if that might be an old split bus panel. Someone could have double lugged off the lighting Main.
I don't think so, Joe. Why would there be a CB at both the upper and lower busses?
 
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Old 11-14-14, 01:34 PM
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Weird stuff going on with that panel. We would really need to pop the breakers out to see the layout of the buses and identify where the large conductors from the top left breaker are going to/coming from. HOWEVER, since there is no apparent main breaker this is risky job. Hopefully you have a disconnect switch out by the meter to kill this panel entirely before poking around in there. Otherwise I would recommend you have the meter pulled before proceeding.
 
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Old 11-14-14, 05:33 PM
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Exiting the main panel it looks like the rigid metal conduit may be used as the ground due to the bonding bushing on the lower right of the picture.
So would it be okay to just attach the grounding wire coming from the grounding rod to the outside of the conduit in between the main electrical panel and meter while still meeting the requirements of the NEC?



 

Last edited by Licentia; 11-14-14 at 06:14 PM.
  #15  
Old 11-14-14, 07:23 PM
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I don't think so, Joe. Why would there be a CB at both the upper and lower busses?
I don't know, Furd, it's a strange setup. When I looked again the red and black wires are not coming from the 2-pole breaker at the top, what are they coming from? From the bus? There is no main breaker. I saw a strange Square D split bus panel a few years ago that threw me too. It was only 12 inches wide.

Weird stuff going on with that panel. We would really need to pop the breakers out to see the layout of the buses and identify where the large conductors from the top left breaker are going to/coming from. HOWEVER, since there is no apparent main breaker this is risky job. Hopefully you have a disconnect switch out by the meter to kill this panel entirely before poking around in there. Otherwise I would recommend you have the meter pulled before proceeding.
I agree with ibpooks, it's strange and needs to be investigated.
 
  #16  
Old 11-14-14, 08:07 PM
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I don't know, Furd, it's a strange setup. When I looked again the red and black wires are not coming from the 2-pole breaker at the top, what are they coming from? From the bus? There is no main breaker. I saw a strange Square D split bus panel a few years ago that threw me too. It was only 12 inches wide.
Here's a closer picture:

However, I'm really only interested in getting a grounding wire from the grounding rod I'm installing to the grounding electrode system. There are also no metal water pipes extending outside of the home.
 
  #17  
Old 11-14-14, 10:33 PM
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It really is looking like the service is not grounded and doesn't have a main disconnect. You may only be interested in getting the antenna installed, but I'm interested in you not getting killed in the process. In my opinion it is not safe to do any work in that box unless the power company pulls the meter and blanks out the pan. That very congested neutral bar right next to what could be unfused mains is a recipe for disaster.

With regard to the grounding, does the house have an old water well with metal casing? Is it possible a grounding wire is buried under the vinyl siding, perhaps running on the surface of an older layer of siding below?
 
  #18  
Old 11-15-14, 04:24 AM
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Find the extent of the existing grounding electrode system starting with #6 or fatter copper wire coming from the main panel (panel with first master disconnect switch or breaker) neutral bus and going to other ground rods and/or main cold water pipe but excluding other plumbing or gas pipes. Connect the #6 copper wire from the new ground rod to any point on the existing grounding electrode system.

If no such fat ground wires exist then your new #6 GEC will be the first and you connect that to the neutral bus (or to the ground bus where both neutral and ground busses have firm metal to metal contact with the panel back or a metal bar between them).
 
  #19  
Old 11-15-14, 05:19 AM
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Looking more closely at the neutral bus and the service cable entering the panel, it appears this is SER cable, but with both neutral and ground terminated on the neutral bus. This might be a subpanel with some problems here.
 
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