# Antenna grounding / bonding in relation to my AC service (with pictures)

I'm trying to figure out how to properly connect new ground rods for an antenna to my main panel. Any advice from those who have done this + have great electrical knowledge would be greatly appreciated.

I plan on hanging a dipole from a tree near the electric service side of my house. I need to ground it and want to install two ground rods (one at the base of the dipole, and another where the coax enters my house). The way that my meter/main panel is set up might not be super common. I had an electrician come out and he thought I could just add ground rods for the antenna and not bond them to my AC service. I'm 99% sure he is wrong since everything I have read says the ground rods must be connected back to the AC service with a continuous #6 wire or larger. I want to have a different electrician come out, but wanted to get a better idea of how things should be hooked up first.

Here is my set up (pictures at the bottom):

Meter

• My meter is on a post at the street ~300ft from my house
• The meter box has a section that is accessible to me that contains a 200 amp circuit breaker
• The meter is grounded via ground rods located in the ground at the base of the meter
• The ground wire in the meter box is bonded to the neutral in this box
• 3 wires leave the meter box in underground PVC conduit: 2 hots + 1 neutral (no ground wire)

Main Panel

• The 3 wires from my meter enter the house through the underground PVC conduit
• My electrical panel in the house is set up like a main panel (not a sub-panel) and does not separate ground/neutral wires for the various circuits
• This panel has a green screw which I think bonds the neutral bus with the panel box and ground lug that I think is normally used for the connection to earth (ground rods)
• Two wires are connected to the ground lug on this panel: 1. My cold water pipe bond (copper service pipe + copper pipes in the house), 2. A wire that goes to a ground lug on my generator automatic transfer switch panel
• There are no ground rods connected to my main panel or my generator transfer switch panel
• My phone and cable service lines also enter the house through underground conduit and are grounded via a clamp on the outside of my main panel (ideally this would be outside, but probably meets code)

Things I'm Wondering

• Can I just install my new ground rods + wire them to anywhere on my neutral bus? Or do I need to install a separate ground bus in my main panel + move my water bond & generator ground to it? Perhaps the ground rods could be connected to the same clamp that my cable/phone service are connected to (I think this may be referred to as an inter system bus terminal - IBT?)
• The ground lug on my main panel having TWO large wires on it looks fishy to me. I'm wondering if this isn't code to have two.
• Does anything seem fishy about my electrical system set up?

Meter by the street ~300 feet from the house

Main panel inside the house

• Bonding to the water pipes replaces bonding to a ground rod at the house. However, local code here now recommends against that, as over years lightning strikes cause pinhole leaks in the water pipes. Dec 31, 2021 at 11:56
• If you feed the antenna with coax, it should have a coax surge suppressor where it enters the house and every 70 ft before and after that and possibly at the antenna as well. The intent here is to drain the (~600v) capacitive charge of the coax in addition to grounding lightning. Dec 31, 2021 at 12:00
• I have two lightning arresters. I'll be installing one right below the antenna and the other will be in the entry panel box where the coax enters the house. I also have 3" ground strap for both of those. I will be installing two ground rods at both locations. I just need to figure out how to properly connect the rods to my AC service :-) Dec 31, 2021 at 12:32
• Grounds that are far away (>100') don't count for lightning. So I'd say don't worry about the meter, it can take its chances. Make sure you have good ground bonding between house earth, coax shield and the actual earth, close to your shack. Without violating code. Jan 4 at 19:26

Grounding is not something where there is a single answer.

First, you should read up on the topic. I found a book entitled "Grounding and Bonding for the Radio Amateur" by H Ward Silver N0AX invaluable as I have several antennas coming into my home and had the same questions as you.

Second, you'll need to understand the code requirements in your area to determine what is acceptable and legal. There is a lot of good information but you want to ensure that you are in compliance for your safety, insurance should something go wrong and avoiding the unexpected.

Third, I'd talk to other hams in your area to pick their brains and see what works and what else you should know.

• thank you for the book reference. Just bought the kindle version! I'm also thinking about calling the electrical inspector in my town to see if he can give me any pointers. I wish I knew an electrician that I trust, but sadly I don't. Also hoping that others viewing my question might have specific pointers based on my electrical setup. Jan 3 at 3:43
• @kr4sh -- electrical inspectors and electricians don't necessarily know much about antenna safety. It's a bit too specialized. I hang out at a diy stack exchange, where questions about electrical issues are quite common, and there are some real experts. But when a question about antennas comes up they don't generally have any special insights. Jan 6 at 13:34

Ideally answer posts should address the entire question post, but the question post posed many questions, so I choose to answer just two of those questions.

Yes, the NEC (National Electric Code, the template electric code that most local electric codes in the US either adopt or adapt) requires that ground rods be bonded together. Most electricians don't seem to know this.

Apparently the minimum size of the GEC (grounding electrode conductor; that's the terminology used in the NEC) depends on the size of the service-entrance conductors. Typical 200 A service requires 00 (2/0) AWG copper or 0000 (4/0) AWG aluminum service conductors, which would require a minimum 4 AWG copper or 2 AWG aluminum GEC to bond the ground rods together.

If lightning should strike close to your house, it would induce enormous voltages in the ground (and everywhere else nearby also, of course) that would then dissipate. The point of bonding the ground rods together is to reduce the voltage differences in the ground in the immediate vicinity of the ground rods, which in turn should reduce the currents induced in every nearby conductor. In other words, bonding the ground rods would reduce the damage caused by a local lightning strike.

The minimum GEC sizes required by the NEC are really recommendations for average buildings across the US, that attempt to balance the risk of lightning damage against the expense of bonding the grounds. You must decide for yourself where to strike the balance. Some hams go much further to protect their stations and their houses against lightning. Tom Rauch W8JI has some great suggestions in this web page.

• That page is fantastic, thanks. He starts with the biggest and most important things up front. Note he has no polyphaser / lightning protection devices, they are much higher up the heirarchy of needs. The only thing I don't like is how the unprotected and protected cables are mingled in his Left-to-Right system, there will be lots of inductive coupling. Better to go Outside-thru_ground-Inside if you can arrange that. Jan 6 at 17:57
• Thanks. I think I put too much info in my question. I basically just want to know where the best place is to bond newly installed antenna ground rods to my AC service given my setup that doesn't have ground rods at the main panel. It just bonds my panel to my cold water pipe. I would consider solutions that satisfy antenna safety and potentially improve my AC ground setup since I believe it is no longer code to only use the cold water pipe as a grounding electrode. Jan 7 at 3:35

I think I missed the original focus of your question because it was so long.

You do not want to bond to the neutral wire in your house. You want to bond directly to the ground rod or water pipes or ground field screen or whatever is your main ground, or as close to it as you can get.

Ideally you want all things grounded to a single point, like a star network, not a chain. Don't ground one thing to another thing that is also grounded -- ground all three things at the same point.

If for some reason, you can't ground everything to the same point, ground it to something you can reach that has the lowest resistance to the central point.

When lightning rod installers install a ground, they get a meg-ohm meter, and measure the resistance. If it is higher than 5 ohms, it is too high and they do something (like drive a ground rod deeper or rebond with thicker wire or something) until it is 5 ohms or lower.

You want your entire ground system to be at the same potential. And when that's not possible, you want to avoid chaining grounds, because that leads to a voltage potential between the first and third thing going through the second thing.

• Yeah I gotcha. I think that central point is the ground lug in my main panel (circled in red in the photo of my main panel). I don't see a way to effectively do that since there are two large wires (cold water and generator bonds) connected there. I'm wondering if I need some type of additional terminal added to my panel that I can move those bonds to, creating a central point that supports more wires. That would take care of my existing bonds and support a new one for the antenna ground rods. I'm going to reach out to the electrical inspector in my town. Thanks for all the replies! Jan 4 at 7:41
• Rather than connect to the ground lug on the main panel, it might be better to try to connect to the thing that the wire on the ground lug connects to. Jan 4 at 12:11

Put up your antenna, run your coax, put the lightning arrestor where the coax enters the house. Ground the lightning arrestor to its own ground rod. Bond that ground rod to your primary grounding electrode (which is probably that same water pipe that your main panel has a run to) using an approved clamp. Don't stuff anything new into your breaker panel, don't re-do any of your existing stuff unless your electrician tells you there's something seriously wrong with the current setup.

• Sounds good to me...except you didn't mention what (wire?) to bond the ground rod to the pipe with. Jan 6 at 3:09
• This makes a lot of sense. I think a #6 solid core or larger wire would be fine for this right? I was thinking to use #4 for the slightly better durability. I'd run a continuous line from my new ground rods to the bonding point (the copper water pipe in my case). I like the simplicity of your answer and that I think it satisfies antenna safety. What still bothers me is I don't like that my panel is grounded via the cold water pipe as the primary ground. Does bonding my antenna rods to the water pipe improve this?Or would I need to bond to my panel to improve overall electrical safety as well? Jan 7 at 3:25
• @kr4sh that last thing is definitely a question for a qualified electrician if you're concerned, I don't think we can give you an answer you can rely on. And yes, #4 or #6 copper wire is the right thing to use (aluminum has too many caveats). Jan 7 at 3:56
• I talked to the electrical inspector in my town today. He discouraged me from connecting the ground to my water pipe and recommended connecting it to the shared ground/neutral bus in my panel. Jan 13 at 14:40

I think you're making too much of your AC service. Your radio components shouldn't use any aspect of your house wiring for ground, except for the 3 pronged plug on a power supply. If you have AC noise issues, you should be looking for bad transformers, including those owned by the power company.

As far as grounding the dipole, I presume you mean the coax shield since a dipole can't be DC grounded. If you're concerned about current on the shield, use a BALUN, preferably a 1.5:1, but plenty of folks use 1:1 with satisfactory VSWR. If you do want to ground the shield of your coax, I'd do it with a separate wire clamped off the PL-259 plug, instead of compromising the jacket of the coax, or using connector blocks on the ground where everything can get compromised by water.

If I'm missing something, please let me know...

• I'm mainly concerned about lightning. I realize that a direct lightning strike is likely to mess stuff up no matter what, but I still would like to take reasonable precautions to ensure that my antenna feed line has a good path to ground (jacket + lightning arrestor). The complexity that I'm dealing with is my meter is far from the house and ground rods only exist at the meter. This is why I went into so much detail to describe my set up. I want to add ground rods explicitly for the antenna feed line, but am unsure what is the best way to connect the rods back to my AC service. Jan 3 at 3:52
• Got it. Obviously the antenna is the lightning attractor, not the radio equipment or AC panel by itself. So a few comments I have on this based on your antenna description are, use insulated wire for your dipole, that has to be better for lightning mitigation than bare wire, and it will be better for DC static build up on windy days, which can still damage your radios front end if you leave it connected. Use an antenna switch with a ground position, and make sure your set it to ground every time you turn off your radio, because that's the only way you can ground your coax's center conductor. Jan 3 at 4:10
• And the bad advice begins. All grounds including the house ground should be connected at a single point. Yes, both sides of the dipole should be grounded -- that's what the coax surge suppressor does. Catch is, half is grounded through a gas discharge tube that doesn't conduct unless there is a spike. Yes, water intrusion is a risk. The polyphaser website use to have a great video on how to protect coax connectors. Jan 3 at 4:38
• The balun advise actually is good. An "air coil transformer" style balun (5-6 loops of coax bound tightly together in a 6-12 inch coil) near the ground actually can help prevent lightning from going down your coax too. Jan 3 at 4:43
• I'm specifically interested in figuring out the correct way to connect new ground rods to back to my AC ground given my somewhat unusual setup (most houses have the meter, ground rods, and panel all at the service entrance). I was wondering if anyone else has dealt with this particular scenario. Thanks for all the other tips though :-) Jan 3 at 5:01