7

I've been looking at how my house is grounded because I want to install an antenna outside for amateur radio. After poking around, I'm suspicious something isn't right. I think I'm probably going to have to call an electrician, but as a first step I was hoping to see if anyone has encountered anything like this before. Ok here we go:

  • My meter is not connected to the house. It is attached to a post by the street approx 300 feet from the house. From there, the line that services my house is under ground and goes directly into my basement via PVC conduit (nothing is exposed above the ground near the house).
  • Inside my basement at the panel, I can see a large gauge stranded copper wire that exits the panel and is clamped in two places on the copper water service pipe.
  • On the same board that my panel is on, the phone service box & incoming cable tv line are grounded via a clamp to my electrical panel (keep in mind this is inside the house).

I cannot locate any ground rods outside of the house near where the electrical service enters the basement. It seems like everything is bonded together inside my basement. From googling, I believe that at one time grounding to water pipes was code, but I'm pretty sure ground rods are also required now. Our house was built in 2009 when the previous house that was here was torn down.

Up by the street where my meter is, there is a ground rod right next to the telephone pole, but I have no idea what is connected to it. I'm attaching some pictures that shows the situation. If my electric service was grounded way out there, would that be legit since the line feeding my house is under ground?

I'm wondering if I need to install a ground rod right outside my basement + tie that to my electrical panel. Then I would be able to put up my antenna and connect it to the ground rod. I'm weirded out that my cable and phone are grounded inside the house instead of outside. Grounding an antenna inside the house seems like a bad idea to me. Anyway, I'll probably be calling an electrician, but would love feedback from your great minds. Thanks!

Meter at the street Ground rod by telephone pole next to meter Ground wire from electrical panel to water pipe Full view of ground wire from electrical panel to water pipe

EDIT:

I took the covers off my panels. My setup is a little more complicated than most because we have a generator with an automatic transfer switch. The electric service enters the generator panel. The generator panel feeds the main panel.

I am reasonably certain that I don't have a ufer ground. In the main panel there are two grounding wires:

  1. One coming from the generator panel
  2. One exiting the main panel and attaching to my water main

Inside the generator panel:

  1. I can see the ground that connects the generator to the main panel
  2. There is another ground that exits the generator panel through conduit that goes to a shutoff switch box on the OUTSIDE of my house.

Inside the outside switch box:

  1. The ground from the generator panel is connected with a nut to another ground.
  2. The connected ground goes into my generator via a conduit.

I can't see any visible indication around the generator that there is a wire exiting it into a ground rod. The only possibility would be if there is something penetrating the concrete slab the generator sits on.

It looks like it would be fairly simple to add a ground rod and either tie it into the ground that is in the outside switch box, OR do that + have it be a continuous wire that routes into the house and connects to the generator panel and main panel.

I'm going to call an electrician. It really seems like my house isn't properly grounded, but also looks pretty simple to fix. Any further advice is greatly appreciated!

Some additional pictures of the grounding:

Main panel ground from generator panel + water main ground: Main panel ground from generator panel + water main ground

Main panel ground from generator panel + water main ground exiting the panel: Main panel ground from generator panel + water main ground exiting the panel

Generator panel ground exiting the house via conduit at the top: Generator panel ground exiting the house via conduit at the top

Generator panel to main panel ground + generator panel ground to outside conduit: Generator panel to main panel ground + generator panel ground to outside conduit

Generator disconnect switch on outside of house. This connects the generator panel ground to a ground that goes into the generator box. Generator disconnect switch on outside of house

8
  • 1
    Quite sure any outdoor antenna needs it's own grounding, a ground wire attached to antenna and/or tower and goes to separate ground rod close by to antenna. Other grounding/lighting protections required for the antenna cable.
    – crip659
    Oct 1 at 22:54
  • 1
    @crip659 I think you are right about the antenna needing its own ground rod (at the base of the tower), but that is supposed to be bonded to the existing house grounding. Then you are also supposed to ground the coax for the antenna where it enters the house.
    – kr4sh2
    Oct 1 at 23:00
  • Am antenna is a large lighting rod, I would not want that bonded to my electrical system. I would want the energy from the lightning to go away from my house, not into it.
    – Gunner
    Oct 1 at 23:12
  • 1
    @Gunner my understanding is if you have separate grounds it can create a high potential between your house ground and the antenna ground. They are connected via coax. I believe this is bad news bears. I'll be sure to get this right when it comes time. Right now I'm just concerned with there not being a grounding rod outside near my panel. Wondering if people have encountered this.
    – kr4sh2
    Oct 1 at 23:23
  • 1
    @kr4sh2 -- you're right, proper antenna installation includes tying the grounds together. You might want to ask in ham.stackexchange.com, where you'll find people who are more focused on radio than general electrical requirements. Oct 2 at 17:01
6

OK, let's talk about the electrical system's Grounding Electrode System first off.

Out at the pole -- and this is not in our jurisdiction (NEC), it is in the power company's codebook (NESC): the pole-top transformer has its neutral wire grounded to a pole-side grounding rod. That is what makes it "neutral".

In NEC territory now, we receive power at the meter, through to the main disconnect switch. Which is almost always a circuit breaker also. That will be the switch behind that little door there. At this point - the first disconnect past the meter -- we have the "service point" and the system bonding. Here, we have another set of ground rods (your Grounding Electrode System or GES) which turns into your house's Equipment Grounding Conductor system. It starts here.

So, 2 different stacks.

  • Neutral: Utility transformer -> neutral bar -> circuits
  • Ground: GES (rods) -> ground bar -> EGC in each circuit.

Further, neutral is bonded to ground here, and this is the only place in your system where it is bonded. Do not bond neutral and ground in 2 places.

Then, power is carried in 4 wires from this point to your house. Since the house is a separate building, it also needs its own GES (ground rods) bonded to EGC (ground wires in circuits).

Now if the work predates 2008, sometimes the run from main breaker into the house is only 3-wire.* In that case, the neutral-ground bond moves to the indoor panel... but again, still only one.

And after that, EGC (ground wires) are distributed normally throughout the house as "that third bare wire" that's in every cable.

So, I would say your next step is to make sure your grounding system is complete, at the panels. The GES wires need to be continuous (not spliced) between the panel and the ground rod.

Modern standard requires 2 ground rods at least 6 feet apart, unless a ground rod passes an expensive impedance test.

Older rules allowed a water main pipe to substitute for ground rods, but that is fading due to the use of plastic water mains.

Also, an "Ufer ground", a rod cast into a concrete foundation, is about the best ground rod you can get!





* I am completely ignoring metal conduit installations where the conduit is used as ground conductor. Because yours is not that.

6
  • 2
    Ufer ground, (bet spellcheck "fixed" it) or "concrete encased electrode" - en.wikipedia.org/wiki/Ufer_ground Required in all new concrete construction in my area, but my concrete contractor failed to install it. How peeved was I - rather...
    – Ecnerwal
    Oct 2 at 0:31
  • Wow this answer is awesome! I'm worried my grounding system is incomplete. If there is conduit going from my meter at the street to my house (100% under ground), it seems unlikely that they would split the conduit under ground to sink a ground rod and then continue the conduit into the house. There aren't any obvious conduits exiting the house for a ground rod. Where would a "ufer ground" be located? On the outside or inside of the house? Any tips on locating a grounding rod? It wouldn't be grounded at the meter by the street and bonded via the super long conduit into the house?
    – kr4sh2
    Oct 2 at 1:09
  • Yeah nice answer. I wonder why they decided to put the meter/breaker out on a post like that? I mean it's always safer to have a short circuit protected feeder rather than an unfused service entrance come into your house. I've seen this done on farms but not in residential neighborhoods.
    – DrSparks
    Oct 2 at 1:37
  • 3
    A ufer ground tends to look like a cable popping out of the concrete - and could be located behind the panel itself if they knew where they were putting the panel when they poured the concrete. Or it may come out the top of the concrete wall.
    – Ecnerwal
    Oct 2 at 1:41
  • For Ufer ground I would look for rebar sticking out of concrete with EGC connected to it, probably hidden behind a blank plate in framing just above concrete. State I live in would have required Ufer ground in 2009, and by ordinance connection to exposed rebar wouldn't have required a separate inspection visit before concrete pour.. Oct 2 at 15:20
1

I decided to make my comments into an answer because I have some things to add:

I don't know if Harper made it clear in his answer, although very informative, but I'd like to encourage you to go ahead and add a couple ground rods to your panel. Just make sure you connect the conductor to the ground bar and not the neutral bar(s). It's common practice for city water utilities to install a dielectric union on your water main to reduce electrical noise on their system.

Also, the ground wire running to your water main needs to have a bonding fitting at the end where the cable exits the conduit to connect to your water main. It's a pretty short run, so it's probably not a huge issue. The reason why is because of the inductive reactance that can occur between the copper wire inside the conduit and the metal pipe. This can be significant when we're talking about thousands of joules during a lightning strike. See photo.

EDIT:

In fact, if that's #6 AWG or better copper wire, you could just get rid of the metal conduit. Or better yet, put it in PVC conduit.

enter image description here

4
  • thanks for the info. I'm leaning towards adding grounding rods. I'm probably going to have an electrician do it. I am just doing research at this point to make sure I'm informed. The conduit that you mentioned on the wall there is actually PVC. It's pretty dirty and the photo isn't great. Thanks for watching out for me though! Tomorrow I'm going to see if I can get a look behind the panel to see if there is a "ufer ground" like others have mentioned.
    – kr4sh2
    Oct 2 at 2:50
  • @kr4sh2 - If you're comfortable doing so, take off the dead front on your panel so you can see the wires inside. Look for any other large, bare ground wires and see where they exit the panel. An Ufer ground wire may connect to a piece of rebar extending out the top of the foundation wall, so the ground wire may go out the top of the panel and into the wall cavity.
    – Mark
    Oct 2 at 6:00
  • From the printing, I'd say the conduit around the ground wire is is PVC, not metal.
    – Ecnerwal
    Oct 2 at 16:45
  • @Mark - I opened the panels today and checked it out. I have two because of having a generator transfer switch. I don't see any evidence of an Ufer ground. I updated my original question with more info + photos. I'm pretty sure my house isn't grounded properly. If you have any thoughts please let me know.
    – kr4sh2
    Oct 2 at 20:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.