I'm sure this is a dumb question, but I just want to make sure. I have an EFHW antenna with a ground. Is it ok to attach the arrestor ground to the antenna ground, or does it need its own? Pic is of the current setup. Please ignore the paracord, it's temporary.

Attached File

Main thing I would do is increase that ground size. If the lightning arrestor does it job that small ground will vaporize instantly. At least #10 or bigger. Can't be too big. #2 solid uninsulated is the preferred size.

People really overdo this stuff. It all depends on whether you care about continued operations after a direct strike or just something to protect from nearby strikes.

Consider that the utilities only protect utility poles with 6AWG copper stranded. Good enough for them, good enough for me. And that's plenty to deal with nearby strikes strong enough to destroy your coaxial lightning arrestor. Anything larger than that, i.e. a direct strike, and it doesn't really matter. You'll be replacing the antenna, arrestor, and ground wire, as they will have all been damaged significantly. So why spend all the extra dough on more copper?

Now if you've got a tower then you need a lightning protection system that stays in service even after a direct strike. That's when you start to see the serious copper, up to 0000AWG on towers above 75ft. See NFPA 780, and also the vaunted Motorola manual. However, even then, how many hams do you know that actually install lightning protection at the top of the tower, i.e. structures designed to attract and route a direct strike before that strike reaches for the antennas? Nobody I know. So even with the tower grounded in accordance with the previously noted standards, all that expensive aluminum at the top is at significant risk.

But for your average backyard wire antenna all you are really able to do is dissipate the nearby stuff, and for that you don't need a ton of copper.

Most bolts are over 1 foot round and jumped a 2000 foot air gap.

You aren't going to protect anything from a direct strike with a lightning arrestor and wire and 1 ground rod.

That is just for RF pulses from nearby strikes.

So the answer is:  it's fine.

Disconnect your radios when not in use.

There seem to be many competing theories on grounding. I appreciate the responses and think I'll leave it as is. And yes, it's tornado season here so I tend to unplug everything when not in use (for the lightning, not the tornadoes ).

I did the "best by far" layout. I did not add the "optional depending on distance" connection.
https://www.w8ji.com/house_ground_layouts.htm

ARRL Grounding and Bonding Book

This is a good read.

My concern with a direct strike isn't protecting the antenna, it's routing the energy to ground safely.

I always plan to disconnect the antenna when not operating, or when a storm approaches.  

Knowing that the antenna could attract lightning, is an 8 foot ground rod at the shack entrance connected to an in-line lightning arrestor enough to give it a safe path to ground, assuming the cable is disconnected a foot inside the house wall?

Basically, I don't want to attract lightning and then have anything other than my antenna damaged.

I know you are supposed to connect to the electrical service entrance ground, but in my installation, it is on the opposite side of the house with a slab foundation so there is no shortcut and it would run into thousands of dollars to do it "by the book".

It still might be cheaper than building a separate ham shack elsewhere on the property.  

Maybe what I need to do is just put an antenna up next to where I park my RV and put a radio in there.  It has almost all the comforts of home, and is isolated from the house wiring.

How do you figure thousands to get your ground to the other end of the house?  Drive in 8' ground rods every 16' and connect them with fat copper wire. I like mine buried in a shallow trench and the ground rod top just below ground level in a small hole covered with thin square of slate (or a rock or whatever to cover the coffee can sized hole) for serviceability.  

75' of #4 solid copper wire:  $125
8' ground rods: $20/ea
clamps to hold wire to rods: $3.50 /ea
Big impact hammer rental to drive in rods: $75/day (you will need only 1 day)
Electrician to tie the last ground rod into your service: $2-300.

What am I missing?

How far away is your antenna from your house?

The reason why I ask is that the house is full of wire. How are you going to stop a bolt from hitting the wires in your house?

You aren't, so why are you worried about it for your antenna. ( a significantly high tower  is a different story )

To route the energy strike safely to ground, if you read the ARRL Book on station grounding, you need 1 acre of ground rods spaced at 16 feet apart and tied together with very big wire or copper pipe.

The common ground, ie station ground bonded via an outside connection to the electrical service panel,  only keeps the service panel ( equipment ground wire ) at the same voltage as your station ground during nearby strikes that produce RF spikes on the wires. Without the large deployment of ground rods, it doesn't really even do that because the thin wire in your house has resistance to it, and the longer it is the more resistance it has. Just like if you make your RF station ground with a 6 wire from the second floor, it is a shitty RF ground. The wires in your house, even properly grounded is a shitty RF ground. the only time this configuration works is if you build a much better ground with an acre of ground rods so that the bolt dissipates in the ground instead of going through the wires in your house. That is why you truly need a circle of effective ground rods completely around the house tied to an acre of ground rods with copper pipe so as the bolt comes out of the sky it sees a rind of very effective grounding around the house and takes the path of least resistance to the circle of ground rods around your house instead of going into your house.

This is all proportional though. So anything you do may help, it all depends on the voltages involved at the time. An RF pulse can be dissipated by a less than optimum grounding system if the Voltage is low enough to be dissipated by your grounding system. As soon as it isn't low enough, it doesn't work.

I content that any system that will dissipate an RF pulse from a nearby strike ( not a direct strike ) will be inferior to just isolating all your ham equipment from the outside world. Nothing plugged in, station ground connected to nothing, all antennas disconnected when not in use and prudence dictates not using it during lightning storm.

But this is just my opinion, YMMV, this is not grounding advice.

I saw a strike hit the neighbors house across the street.

the bolt hit a short piece of rebar sticking in the ground on the other side of the 2 car driveway. Found an irrigation pipe with water in it. traveled through the water blowing up the pipe and the driveway producing a 2 foot deep ditch and driveway pieces thrown 50 feet in all directions, then came back out of the ground jumping 15 feet into the air into a security light over the garage doors and entered the house and caused damage to many electrical devices and a smoldering fire in the wall.

he had no antennas. my equipment was disconnected and suffered no damage. may house is about 100 feet away or so from where it hit the rebar which was used as a property stake.


I am not trying to dissuade anybody from building a grounding system, I am just trying to inject reality into the discussion to show you really have no control over where a lightning bolt goes by having a  few grounding rods and connecting them to the service panel. It might even cause extra damage by injected some unwanted voltage into the service panel when it might not have gone there without the grounding system.

Now you all are just rehashing the third post in this thread (mine ) where I note that the measures most hams take or are capable of taking are only going to protect connected equipment against nearby strikes and, with the right arrestor (Morgan Mfg), dissipate static charges. The things we generally do, even the best of us, do NOT protect from a direct strike, and will have little bearing on what a direct strike is going to do.

To be somewhat repetitive with respect to direct strike protection, unless you are putting in a grounding and lightning protection system that meets the NFPA and Motorola standards, don't even worry about it. And since it's too big a leap for any ham that doesn't at least have a tower then, again, don't worry about it. All that wire will vaporize long before the lightning can get anywhere on it.

Like I said, I don't care about the antenna being destroyed.  An antenna and feedline is going to be cheap to replace compared to house wiring.

My question is, is there any cost effective way to prevent lightning from damaging house wiring (assuming the antenna is disconnected from the radio equipment) in the event lightning hits the antenna?

If the answer is no, then I guess I won't worry about it.  But knowing it could happen, my wife will absolutely lay the blame squarely on my nerd hobby if it does.

With the size of, /numbers of charges in lightning the name of the game comes down to surface area. If your really into this, run multiple radials from each ground rod out over the area. This will give the charges a place to go as the impedance of the deep ground rod limits how many charges it can dissipate. I got the notion from a fellow I worked with, who had some military communications experience. The difference between two separate setups was the one with the radials deployed survived a strike, the other, not so much. The ability to dissipate comes down to low impedance and that's surface area in a conductor.
73,
Rob

@Jambalaya
I ground my HF antenna outside the house. That ground system consists of multiple ground rods tied together with #6 solid and connected to the house ground. With the dipole grounded, I hope it begins to dissipate charges before they can build up.

Once upon a time, in a rental, I had lightning strike the push up pole, the antenna was disconnected. The strike went down the pole, into the ground rod and then jumped to the copper water line going toward the street where it blew hell out of the water meter.  The water line, under ground, was probably three feet or so from the ground rod. The strike also blew  a few GFIs and the starter capacitor on the fridge compressor motor which was just inside the house opposite the push pole. I figured that was induced. We were not home at the time.