OK To Add A 2nd Ground Rod?

[CanesFan95]

The more I try to read up on grounding for lightning safety, the more I come across opposing debates and can't figure out what is right or wrong. It seems like no matter what someone does to ground an antenna, there's always someone on a forum who'll tell you you're doing it wrong. Doesn't even matter what you do. Randomly set up something or do it by the book and someone somewhere will always say you're wrong.

Like this thread for example, where there's a guy on there who insists that you shouldn't add more ground rods to a house. But then there's other times I'll see a thread where someone says to add another ground rod and "bond" it to the original ground rod (I believe "bond" simply means connect 'em with a piece of wire?).

If the goal is to ground the antenna and mast in as straight a path as possible directly down, then the problem is you might not be able to place the antenna right next to the original ground rod. So final answer, is it OK to add another ground rod or not??

 

[prcguy]

There are rules to follow, not mine, not other RR members, but the National Electrical code. NEC basically states you can add as many ground rods as you please but they must be bonded to the house main electrical entry point ground with no less than 6ga copper wire and when the distance is over a certain amount you may have to upsize the wire. Further research shows you should not put ground rods too close together or they can actually reduce their effectiveness in dissipating a lightning strike. The general rule is space them twice the distance apart as they are long, so two 8ft long rods would be at least 16ft apart, two 10ft long rods would be 20ft apart but each site is different and certain factors may change that distance.

Further research shows the connections to the ground rods should be as short and straight as possible eliminating any sharp bends. Again, not my rule or anyone here, its the accepted industry standard based on testing and facts. To find out more about NEC requirements, do a search on NEC Article 810, which deals specifically with antenna grounding.

 

[mmckenna]

I hate to say this, but I've found it to be true over and over again:

Don't listen to advice on QRZ, and take anything an amateur radio operator tells you with a couple of grains of salt.​

​

That may annoy some, but you really need to be careful with the source. There are absolutely some hams that know what they are doing and will give you solid advice. prcguy is a ham and is telling you the truth.
But I've found that 'random dude on QRZ' is not an authoritative source, and they'll argue things to death and not get anywhere. Most of it is not based on any sort of fact, code, rule or anything else. It's the opinion of some guy on the internet. What's worse is that they all assume they are some sort of expert.

If you want good info on grounding, you need to take a look at the National Electric Code (authoritative source). You could also take a close look at Motorola R56 document, which is based off the NEC and adds a lot of good info to it.

It is not at all unusual to have multiple ground rods at a radio site. Usually they are set up in a ring around the tower and hut. All the rods are bonded together, bonded to the tower, bonded to the electrical system, bonded to the generator, bonded to fence, bonded to the HVAC system, bonded to the racks, bonded to the cable tray, etc. etc. etc.

Adding additional ground rods may be required if there isn't a ground rod at the antenna support or tower. It also may be required if the ground resistance isn't low enough with one rod.

The 'random dude on QRZ' doesn't know what he's talking about. The original question on that QRZ thread could have been answered easily in one post. Why it dragged out onto 8(!!!) pages is just indicative of the kind of advice you get from there. It's an easy NEC/R56 question.

 

[CanesFan95]

You notice how the ground rod on houses is usually right under the electric service meter where the overhead power lines come in? But most antenna instructions warn to not install the antenna neat power lines. So how else are you supposed have the most straight-down path to the ground rod? Those antenna manual warnings seam like a contradiction. If anything, most satellite dish installs I see around town are right next to the power lines, so to be closer to the ground rod.

 

[mmckenna]

They are aimed at consumer safety and meeting the NEC.

 

[AB5ID]

So how else are you supposed have the most straight-down path to the ground rod?

Place a ground rod under the antenna, just make sure all ground rods are bonded to the AC mains ground.

 

[CanesFan95]

So let's suppose the antenna is at the back of the house, ground rod/electric meter is at the front of the place. And there's a corner to go around, so it's not a straight path to add a 2nd ground rod. What do you do?

A. Don't add any more ground rods and run a long 10 AWG wire all the way around the house to one of the available ground panel screws by the power meter?
B. Add one additional ground rod at the back of the house and run a long 10 AWG wire from the new ground rod to one of the available ground panel screws by the power meter?
C. Add multiple 8-foot ground rods 16 feet apart, connect them all together with 10 AWG wire, and hook one last piece of 10 AWG from the last extra ground rod to the one of the available ground panel screws by the power meter?
D. None of the above.

 

[mmckenna]

So let's suppose the antenna is at the back of the house, ground rod/electric meter is at the front of the place. And there's a corner to go around, so it's not a straight path to add a 2nd ground rod. What do you do?

A. Don't add any more ground rods and run a long 10 AWG wire all the way around the house to one of the available ground panel screws by the power meter?
B. Add one additional ground rod at the back of the house and run a long 10 AWG wire from the new ground rod to one of the available ground panel screws by the power meter?
C. Add multiple 8-foot ground rods 16 feet apart, connect them all together with 10 AWG wire, and hook one last piece of 10 AWG from the last extra ground rod to the one of the available ground panel screws by the power meter?
D. None of the above.

Doesn't have to be a straight path between the ground rods. A bend is fine. You want to keep the bends gentle.

I'd add a ground rod under the antenna and bond that to your homes existing ground.

If you were doing this at a commercial site, you'd do a ground resistance test to see how many ground rods you'd need. 5Ω or less is the goal. Since most home owners/radio hobbyists don't have ground resistance meters, you do the best you can.

In a perfect world, you'd contract out a specialist and have them design the system for you. Also out of the reach of most hobbyists.

Option E: Don't get stuck on this. Run in a ground rod under your antenna and bond it to the home ground. Be happy, have a cold one and enjoy your radio.

 

[prcguy]

A version of "A" is applicable to meet code. B would be illegal due to the wire size, needs minimum of 6 AWG copper. C would be illegal due to the wire size, needs minimum of 6 AWG copper. D would not be legal.

A Dish or DirecTV installer looks at two things when they survey your house for an install. A good line of sight to the satellites and a 30ft or less run of ground wire to your AC electrical panel ground. Commercial installations can use any metallic conduit on a roof that has a home run to the AC panel ground. Somewhere I have a little badge that claims I'm an SBCA satellite installation trainer and I had to convey all this to new recruits a long time ago.

All of the NEC rules are for human safety and not necessarily to survive a lightning strike, so to meet NEC you can run a good length of 10 AWG wire to ground your lightning arrestor or coax around the corner and be legal but if the run is over about 35ft you should upsize the wire depending on the run.

To survive a direct lightning hit is beyond the scope of anyone here including myself and that requires professional engineering to R56 and beyond and that is going to be costly in both engineering services and modification/construction to your house. In my opinion the worst thing you can possibly do is follow someone's advice or even the NEC and think your are protected from a direct lightning hit. Just know that you are not and deal with it by disconnecting your antenna cables and getting them far away from anything or take other steps to protect your radios and household electronics before the electrical storm reaches you.

So let's suppose the antenna is at the back of the house, ground rod/electric meter is at the front of the place. And there's a corner to go around, so it's not a straight path to add a 2nd ground rod. What do you do?

A. Don't add any more ground rods and run a long 10 AWG wire all the way around the house to one of the available ground panel screws by the power meter?
B. Add one additional ground rod at the back of the house and run a long 10 AWG wire from the new ground rod to one of the available ground panel screws by the power meter?
C. Add multiple 8-foot ground rods 16 feet apart, connect them all together with 10 AWG wire, and hook one last piece of 10 AWG from the last extra ground rod to the one of the available ground panel screws by the power meter?
D. None of the above.

 

[n5ims]

One reason you get conflicting answers is many folks do not understand the difference between a safety ground, a lightning protection ground, and an RF ground (sometimes called a ground plane or even counterpoise). You may be asking about one of them and they answer for a different one (perhaps even the correct answer for that one, but still wrong for what you were asking about). You could clarify what you're really asking about in your question but most of the time that won't help since to them a ground, is a ground, is a ground.