Importance of Bonding to Utility Ground (
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- čas přidán 26. 05. 2024
- Vin has a question on bonding ground rods. His two grounds are 100 feet apart and is wondering if it would matter to bond them because the distance seems far longer than it should to be effective. Watch to learn more on how the distance does or doesn't effect bonding the grounds.
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I’m a retired electrical engineer living in Florida and have thought that even if you follow all the methods that Dave is suggesting, which are excellent, there is still a risk with lightning. So, rather than taking on that risk, EVERY time I turn off the station, I disconnect everything from the electrical outlets (one master outlet box) and disconnect all antennas and place the cables outside on a concrete slab.
Not unreasonable, and certainly mitigates all risk.
I had a rig destroyed by lightning where my coax was in the shack and 5 feet away from the radio. It took out the grounded radio and the computer. Grounding does not help. It's more dangerous for your radio because it attracts lightning better.
So yes, I agree that your coax end needs to be outside
I also have been hit by lightning a direct antenna hit I lost everything and almost my life
My #1 rule is always run coax to outside barrel connector and always always disconnect for storms and move house coax away from antenna coax so it won’t jump across
That’s all ya’ll have to do and should be doing if you value your life or families lives
For storms make a storm antenna it can be in the attic something to keep you on the 2m repeater during a lightning storm or use an HT
But never never never think a lightning arrestors is gonna save you or you radios or your house or life because it’s not and is a waste of money and another connection point in your coax
Just use barrel connectors and separate the house coax’s from antenna coax’s and sleep just fine not worried you may loose an antenna if your hit but your radios and house and life’s will be fine
Got it and agree. Putting in ground rods isn’t, at least where I live a casual thing. Between clay and rocks it’s a real task.
Are you using an impact hammer with a driver attachment to drive you ground rods? I have gravely silty soil and it is no fun to do the driving with a sledge hammer. I used a rotohammer drill and it was a breeze.
Excellent presentation Dave.
I can take this up another notch. The Motorola R56 standard also specifies a bend radius for the ground wire. Otherwise lightning will launch off the ground wire.
I see many antenna or tower grounds with sharp angles that are good for static buildup drainage, but will be ineffective during the ill fated direct strike.
The reality of lightning in a direct hit is there will be melted copper splattered wear the ground wire was.
Bottom line, do what you can, and you should survive all but the big one.
Best CZcams video I have seen. I take his words as scripture. I hook insects up to computers to monitor feeding signals from the muscles and fluid flow. These signals are very, very small. Noise is a problem. This video helps me to reduce that noise.
Thanks!
Excellent video sir. Thank you & 73, Mike K2CDM
Bonding is for safety. If you have RF currents, you need to resolve that before the bonding point. You don’t want RF power on your bonding line. Also you should have a ground rod at any antenna to increase chance lightning goes into the ground and not follow your bonding wire around the house.
Putting in grounds along your transmission line could increase your common mode currents.
Time stamp 4:20 -- VERY well pointed out. Earth, soil, has resistance. E-IxR !! Listen to the OG, old guy.
After a lightning strike: the well engineered system sees nothing.
A lucky person has that voltage difference go through the equipment and burns out the Yeasu radio.
The unlucky person has the voltage go through them.
The possibly sued person has the voltage go through a guest or other family member, burning or killing them. "Electricity takes ALL paths to ground"
I apologize for that sounding preachy. Just think it through.
I confess I need to ground my antenna supports and add a few ground rods. I use "acorn nut ground rod clamps" to bond - that is me, no legal suggestions made. May look at the welded approach.
(smiles) Yes my shack, very small, is also diametrically opposite the service entrance. It was not planned that way.
BTW, even the electric company has to replace ground roods as they go bad. Driving ground rod can be troublesome. Some soil is rocky or sandy.
73
Correction: As a Licensed Fire Protection Engineer, I can tell you that the National Electrical Code is actually NFPA 70. NFPA is the National Fire Protection Association, not National Fire Insurance Association.
that is what I have been working on one side and the back to donce, starting on another side then the front.
An electrical supply house has the cheapest price on grounding wire.
So I have to a question... IF your station is NOT connected to house wiring, is bonding even necessary? My station is connected to 200 Ah LiFePo battery. I use solar and a battery charger (used only if necessary, like in winter) that is connected to house power only during charging otherwise it is disconnected. There is a ground rod and lightning arrestor for the antenna just outside the station window prior to coax entry inside.
I have no option for a ground rod where I live, when the house was built the entire property was surrouneded by cement (Inner city). I can access the main ground electrode system, but cannot add another. Is it safe to connect my shack grounds to that?
Not only is it safe, it is imperative!
Concrete encased earth electrodes are fantastic in terms of function.
@@denverbraughler3948 Thanks, and ground both the station and the antenna to this? :) (sorry, newb here)
@@randomcrap763:
Your house electrical system must already be connected to the GEC.
(If it isn’t, that’s a major error. The connection must be from your house panel to the grounding electrode system.)
Your indoor equipment connects to the grounding electrode system via the house electrical system, and to the antenna grounding system via the shield of the antenna cable.
An additional connection from your entry point to your rack or equipment shell isn’t mandatory unless you actually have a problem with stray voltage, that is, if you can read milliamps or volts between outside and inside grounds.
I am a cable system ytech of 20+ years if you donnt invclude building ground could create potential other wise known as " electricity" it travels to you or to your home werever it picks
One thing I find a little baffling here is that my coax shield is already grounded, though I haven't installed a ground rod system yet (I'm in a low-risk area and disconnect the coax when I'm not actively using it). This means that the coax is connected, through the radio, directly to the negative terminal of my power supply, which it turn is connected to the ground pin of the electrical outlet. I can plug a probe into that pin of any socket in the house and run a wire to the outside of the coax and there's already continuity there.
Obviously the ground rod system with lightning arrestor is there to take the radio out of the circuit when lightning hits, but shouldn't common mode current already be dealt with, if the coax shield is _already_ grounded?
Would seem so, but doesn't work that way in practice. Put in a station ground rod and "bond" it to the utility ground.
@@davecasler I'm in the process of doing just that, for other safety reasons. I guess the common mode noise issue is a thing I can test at each stage of the install; my QTH in fairly urban and there is a ton of noise, so if any of that is coming from the grid and making it into the receiver, any cutting of common mode noise should be immediately audible.
can you clarify #6 please, #6 to wire size has no meaning in the UK. love you videos, thanks
AWG 6 = American wire gauge 6. This is the smallest recommended size.
The specifications are 4.11 mm diameter, 13.3 mm² cross section.
Although more but smaller strands are beneficial, they are less durable. So coarse strands are preferable.
Flat braids are beneficial but not as durable as round wound conductors.
Outside diameter is the most important. But it’s useless if it breaks.
@@denverbraughler3948 I've used 6mm as in video but it just seems to work like an antenna, when i connect to my radios system my noise level S9 on almost all bands, remove it and i get s2.
@@theDaftman:
You’ve possibly created a better ground than your utility company has. Check for AC voltage and milliamperes across the point where you disconnected it.
But if it’s an antenna, does this mean that you didn’t connect it solidly to earth at both ends and bury it?
@@denverbraughler3948 (if it’s an antenna, does this mean that you didn’t connect it solidly to earth at both ends and bury it?) my radio Shack / workshop is on a second floor, sow the length of the cable coming up to the shack is where the problem is, think, it's a terrorist house, (houses attached at both sides) ground cables are bolted at both ends, I lifted the floorboards in the front room, new ground rod (Earth) installed for the mains house as it was bolted to the equivalent of a 6 inch Steel nail. I also replaced the earth cable up to the main consumer unit with 6mm cable, the original was a 3mm. With the new ring main ground rod installed i installed 2 more (making 3 ground rods) in a 12 foot triangle and linked all 3 with 6mm stranded cable in the ground so all cables buried about 1ft including the tops of all 3 rods. This was the max I could practically install.
so house mains earth to one rod, all 3 linked, shack/workshop connect to another on of the 3 earth rods and 6 mmm cable up the shack/workshop. in the shack/workshop the end of the 6 mmm cable goes to a copper plate (not bus bar) with bolts wing nuts and washers,
my radio system is set out in a way that all the Earth cables from that copper plate are all equal in length.
I also have mains filtering on the entire supply to the shack/workshop. I have ferrite beads on all antenna cables, chokes on one-to-one balance where appropriate. I even have the radio Shack/workshop on emergency push stop switch. Most say I've gone well Overboard. now if I set up a radio on the bench regardless of frequency adding the Earth put the noise level around S9. even Faraday all the walls and roof and floor in the shack/workshop just to see if it helped, but on it did not. removing the main shack earth wire nose drops significantly. I've been working on this for over 3 years to no avail. I'm at the point of giving up with being a ham operator.
When you say to ground it at the antenna, how do you do that? I thought you go down from the antenna with coax into the lightning arrestor connected to a bus bar on the house. Then you take copper wire from the bus bar to the grounding rod. Is that what you mean by grounding at the antenna, or am I missing something?
My power comes in on the other side of the house and no matter what I would need to get under concrete to reach it. The gas service is right next to my antenna. I would assume it is grounded but I guess that would not count it would need to be grounded to the power service only?
You missed that you also put a ground rod at your antenna so that lightning has no reason to go to your shack.
If you own the gas pipes, that is, they are on the customer’s side of the meter, bond to them.
As for bonding to your house electrical grounding system, several possibilities exist.
Laying copper all the way around one side of the house is a good choice, such as AWG 4 or 6 solid.
Connecting to rebar in the concrete slab that’s connected to the house electrical system also works.
@@denverbraughler3948okay but how do you ground to an antenna? I come out of a X50 antenna with coax. Where do I connect a ground to the antenna? I understand if it is a vertical with ground radials but how do you do it when it is not that? You are very kind to answer my questions thank you!
Don't bond to gas pipes. Dangerous.
My shack is located on the second floor. Athough I've installed a few rods approximately 12 - 16 feet from my shack to the utility ground, I'm concerned about the stranded wire running from my shack to a grounding rod approximately 15 feet below a shack window and wonder if anyone has suggestions on best practices in this case. Thanks & 73, Dave KF2BD
Consider why you need a ground rod. It may not be necessary. My station does not have a ground rod. As a new teen age ham I put one in. Later as an electrical engineer I never used them for my station. Some antennas such as ground mounted quarter wave verticals with radials do use the ground. I would never leave that ground connected to my station when not in use. If I did I would be sure to bond it to my electrical panel ground rod. I can’t see any value in a long ground wire from the second story to the ground rod. The ground rod itself does not make good connection with ground. Two ground rods were required by my city in the last house I built! The contact area of a single ground rod with the earth is not much. Contact resistance is going to be high.
@@dandypoint:
As an electrical engineer, you know that resistance depends on frequency.
And for constant current sources like lightning, voltage is whatever it takes.
If your ground rods don’t dissipate it, it’s going onto the grid.
If there’s no stray voltage (e.g., 3 V AC) and no milliamps from your coax cable shield from the antenna to the house electrical ground, then you don’t need to run an ground in additional to your grounded coax cable.
@@denverbraughler3948 yes. What appears as a low resistance/ impedance to DC, such as a 20 foot number 12 wire, has significant impedance to various RF frequencies. Different impedances for different frequencies. There are many grounds and many reasons for a ground. Safety, lighting and sometimes RF. They can’t all be treated exactly the same. You can reduce your lightning risk by disconnecting the antennas and using lightning arrestors. Lightning damage may still happen to a house with no antennas. My best advice to hams is not to violate the NEC knowingly. The NEC is not even fully understood by some inspectors but most err on the side of safety, such as insisting on a ground rod for a fiberglass pole when even a ground rod for a metal light pole does not really make it safe.
@@denverbraughler3948 I wondered about that myself (in another comment) as I checked for and found continuity between coax shield and house ground. I'm putting in a ground rod for a lightning arrestor to work with, but the length of run to the utility ground is very similar to the question posed in the video.
For that much copper, just run your station off a battery with no connection to your home electrical system. Disconnect everything and recharge that battery when done. Making a floating system removes any need for bonding to your home ground system.
Unless you have a tower, odds are higher that you will take a hit on a nearby power pole. Regardless, you should at least three layers of protectors starting with one rated for 100-200 amp service, 30 on the subs and protected power strips. Also, following your powerline a ways looking to see that your power company has protectors and they are intact.
A 100' horizontal cable with a kink isn't going to provide much lightning protection. Lightning strikes hard (huge currents) and fast. Cables like that have too much inductance and the lighting will often jump past the cable to ground. Lightning protection needs to be straight giving a clear and easy path to ground. No loops. Even partial loops (curves) need to be avoided or made as large as possible.
There are sailboats struck by lightning where the lightning blasted through the fiberglass hull rather than taking a cable down the mast and around the side of the ship.
If you want to protect sensitive electronics, disconnect them and hide them in a Faraday cage. EMPs generated by lightning strikes can destroy cell phones 1/4 of a mile away.
I'm not an expert on the electric code, but I think the grounding of subpanels is a serious issue. Specifically, they are usually not grounded locally for safety reasons. A second ground can allow currents to bypass safety equipment. Check with an electrician familiar with the code before installing powered grounds. (Grounds for antennas are fine, but don't allow line voltage fault grounds even through equipment case grounds.)
Several ground rods are needed for lighting protection as Mr. Casler stated. It's better if they are in a star pattern though. (These provide antenna good grounds as well.) If your soil is sandy, you will need salt wells rather than simple rods. The salt is usually in a gel matrix but still needs maintenance. (For best practice. This is expensive and most amateurs will likely go with something way simpler.)
For grounding ships, a large copper area (I forget the size needed, but it's around a square meter.) built into the hull under the mast is needed on salt water. (Bonded to the mast cable.) On freshwater (higher resistivity), the amount of copper required usually exceeds the size of the hull, so live with the lighting holes when they happen. (Fortunately, lighting on the Great Lakes is less of a problem than in Florida.)
Lightning strikes follow a path along ionized air felt out by feeler fingers that develop milliseconds before the main current flow. These feelers are formed by (more or less) static electricity. They provide a low resistance path to the ground. Sticking a ground high in the air (like an antenna) will encourage the feelers even if the antenna can't support the main strike current.
Another option is a resonant cavity tuned to allow your band to pass. This breaks the DC path the feeler needs to form. Have a lightning arrestor on a straight path bypassing the cavity. The idea is that the lightning takes the straight path across the arrestor gap rather than going down your signal cable, across the cavity gap, and into your equipment. Your sensitive equipment still needs EMP protection though. A metal case and surge protector maybe.
So, a long convoluted ground wire will allow the small feeler current, but the main current will mostly skip the ground wire. (There's enough voltage and current that a fair amount will go that way too.)
There is no panacea for lightning. It's been known to skip around everything we try to do.
Every panel may be grounded and must bonded locally.
Additional grounding doesn’t bypass anything whatsoever.
The restriction is that the neutral and ground must be bonded at and only at the first point of service.
The equipment grounding conductor must be installed everywhere in parallel with ungrounded conductors.
It’s omitting the equipment grounding conductor that creates a safety hazard.
A ground rod is not a substitute; it’s a supplement.
@@denverbraughler3948 Thank you for clarifying.
the water and gas is plastic , the mains are plastic. .
If mains are plastic outside, that’s the same as if they aren’t there.
If the gas lines are plastic indoors, that’s a serious error.
When connecting to piping always assume that it could be disconnected, removed, or even replaced with plastic or dielectric couplings in the future.
Wow, having just watched the ARRL talk by Kristen McIntyre, K6WX “Ground is a myth” on which you commented - she says she sees no need for a ground, except lightning. What gives ?
That refers to RF ground. And yes. Unless you have a vertical that you feed between antenna and ground rod, no need for low RF impedance connection to ground. But he's talking about lightning protection. Different story.
He's done this topic before
Yes well. I rent.
Totally unnecessary if you disconnect antenna cables unless you are operating in good weather. Especially if you are using portable antennas.
* Totally necessary because there are many types of electrical anomalies that are not related to local lightning strikes.
@@denverbraughler3948 Using your logic, I would have to drive a ground rod at my picnic table when running POTA and run a bonding wire to the service ground of the park office.
@@firemarshal17:
The topic is indoor, grid-connected equipment and outdoor antennas.
If you change the topic to a temporary outdoor setup not connected to grid power, expect a different answer.
I have been told by electricians in VK that I should NOT bond my antenna/radio earths to the house earth as it stops the Safety Switch in the house fuse box from working correctly, but we do have different house wiring to the USA. We use the MEN System (MEN being Multiple Earth Neutral).
Did you ask for a diagram showing how tying grounds together stops the safety switch from working?
Trace the topology and see for yourself. As long as your ground conductor has a continuous copper path to your neutral, there no possibility to bypass anything.
However, you do have a problem if your neutral is your only grounded conductor as it carries current and has a potential greater than ground. You need a parallel equipment grounding conductor that grounds only frames and shells, i.e., three-prong plug and receptacle connections served by three copper conductors.