PDA

View Full Version : Grounding. I need to pick your brains.



W5BRM
09-15-2013, 04:10 PM
Been running over ideas about grounding in my shack. Question about safety ground i.e. grounding my equipment.

Been researching a bit and I'm getting confusing answers. I want to ground my equipment.

I have a HF rig, Antenna tuner and a power supply. Each has a tie in for a ground strap.

I plan on setting up like this: Each peice of equipment will have individual short braided copper lead to a copper bus bar. Copper bus bar will have one short 5-6 ft x 3 inch copper strap going to 8ft ground outside the shack. All short lead stuff.

I get confused after this.

Should I run more then 1 ground rod into the ground spaced so far apart maxing out at 3 ground rods?

and THIS IS THE REALLY CONFUSING ONE:

SHould this ground system run to the house grounding where the AC line comes into the house?

I have been researching this on the net and I get conflicting answers... I had always been taught that one should never tie into the house or service ground... i think this is probably incorrect but im not sure. Some people say that tie into the house service ground, you risk setting up a ground loop and energizing your equipment which is bad. Others say isolating the equipment from the service main does the same thing and creates lightning hazard.

If I should tie into the service ground, do I need to direct tie my ground rods to the service ground rod with copper wire or can attaching a cold water line to my ground rods do this for me?

Which way should I do this?

I am away from the house and dont have any access to my ARRL books and the ARRL has all thier important info parked behind the pay wall....err i mean members only area

Thanks

Brian

PA5COR
09-15-2013, 05:06 PM
I have the same setup on the ground level here, 3 10 feet long copper pipes in the ground each 10 feet from eachother in triangle formation each cadwelded with very thick wire to eachother and the ground from the house ground, mandatory here to cconnect all grounds to eachother.

That way the ground from the electricity service and your safety ground won't see a different potential when the lightning strikes.
The connecting massive copperline is 1/4 inch and cadwelded to the groundrods and the service ground.
And to the 3000 feet of copperwire in/on the ground serving as ground plane for the inverted L, which each are grounded on the end with a 8 feet copperpipe as well.
The last bit was not needed, but i had enough of the pipe to be used for it anyway.
Check your local code how to setup the ground to the service ground.

WØTKX
09-15-2013, 05:14 PM
One of the best resources on the net for this topic.

http://www.w8ji.com/ground_systems.htm

W5BRM
09-15-2013, 05:19 PM
I have the same setup on the ground level here, 3 10 feet long copper pipes in the ground each 10 feet from eachother in triangle formation each cadwelded with very thick wire to eachother and the ground from the house ground, mandatory here to cconnect all grounds to eachother.

That way the ground from the electricity service and your safety ground won't see a different potential when the lightning strikes.
The connecting massive copperline is 1/4 inch and cadwelded to the groundrods and the service ground.
And to the 3000 feet of copperwire in/on the ground serving as ground plane for the inverted L, which each are grounded on the end with a 8 feet copperpipe as well.
The last bit was not needed, but i had enough of the pipe to be used for it anyway.
Check your local code how to setup the ground to the service ground.

Ok so i should connect ground to the house service... Can this b done thru connecting to cold water pipes or do i need to run a line all the way from shack to the house service? Its a looong way. They are exactly opposite corner from each other and its about 100 ft via perimeter run vs 4 ft to an outside waterline spigot.

K7SGJ
09-15-2013, 07:35 PM
I've always subscribed to "any good grounding is better than none at all". If the cold water pipe is close, use it until you can improve on it. So long as it isn't PVC, that is. I would probably augment that with ground rods when possible. I'd follow Dave's advice and follow the link. It is the best site I've ever found on the topic.

KC2UGV
09-16-2013, 07:34 AM
To sum up: All ground is ground. All ground should be equal. If you have two separate ground, that are not bonded, you run the chances of having potential between them, and a "ground loop".

So, all electrical safety grounds should be tied to the same thing, or bonded together.

Now, that being said, why are you grounding your equipment?

KJ3N
09-16-2013, 08:08 AM
To sum up: All ground is ground. All ground should be equal. If you have two separate ground, that are not bonded, you run the chances of having potential between them, and a "ground loop".

As previously discussed here, there are (generally speaking) 3 types of "ground": 1) Electrical Safety, 2) RF, and 3) Lightning. Nothing says those are all the same thing.


So, all electrical safety grounds should be tied to the same thing, or bonded together.

True.


Now, that being said, why are you grounding your equipment?

Probably, "because the books say I should". I don't believe everything I read in books, and especially what I read on the Internet(s). ;)

I've never bothered to run any additional grounding of any kind. In certain situations like 2nd floor shacks, they will often cause more problems than they solve. My rule of thumb is to add grounding only when there's an actual problem.

My equipment is plugged into a 3-prong AC outlet, which is my Electrical Safety ground. My antennas are dipoles and loops (which are balanced antennas that require no RF ground), and a couple of verticals with their own radials, that serve as the RF ground for those antennas. As to lightning ground, in the 10 years I've been here, I can think of only 1 strike that came close. It struck a neighbor's tree, which is higher than any of my antennas. I also have a 1,000 foot FM broadcast tower less than 1/4 mile from me. If anything is going to get hit, it's going to be that structure.

As always, YMMV.

KC2UGV
09-16-2013, 08:52 AM
As previously discussed here, there are (generally speaking) 3 types of "ground": 1) Electrical Safety, 2) RF, and 3) Lightning. Nothing says those are all the same thing.


Agreed, however, it appears he was asking about electrical grounding, which is what I meant that all grounds are the same, and should be.



...Probably, "because the books say I should". I don't believe everything I read in books, and especially what I read on the Internet(s). ;)

I've never bothered to run any additional grounding of any kind. In certain situations like 2nd floor shacks, they will often cause more problems than they solve. My rule of thumb is to add grounding only when there's an actual problem.

My equipment is plugged into a 3-prong AC outlet, which is my Electrical Safety ground. My antennas are dipoles and loops (which are balanced antennas that require no RF ground), and a couple of verticals with there own radials, that serve as the RF ground for those antennas. As to lightning ground, in the 10 years I've been here, I can think of only 1 strike that came close. It struck a neighbor's tree, which is higher than any of my antennas. I also have a 1,000 foot FM broadcast tower less than 1/4 mile from me. If anything is going to get hit, it's going to be that structure.

As always, YMMV.

Which is why I'm asking. Oft times, just grounding electrically to your third prong is sufficient. I ground all the equipment to the power supply chassis, which has a third prong, and I go not recall any issues that could be attributed to grounding issues.

PA5COR
09-16-2013, 08:56 AM
Not true that living next to a high structure saves you from getting hit.
My parents ( deceased) lived near a 14 story apartent building topped up with a metallc structure holding lots of antenna's on top of it all bonded liberally with thich ground wires running down the apartment building to ground.
10 meters from that 180 feet high structure was a cental antenna box 3 fet high.
Containing amplifirs annd stuff.
That one got hit not the 180 feet higher apartment building 30 feet away from the box....
Don't assume that you will be safe if a high structure nis next to you, always assume the worst case scenario.
I do, and i have the ground here for the inverted L and the safety ground for lightning strikes.
Several antenna's are 30 -40 feet higher as the house here, i don't take risks.
Read the supplied link, it is a good one.

W5BRM
09-16-2013, 08:06 PM
ok thanks for the replies guys. Main issue is that I think I am going to have to rework my electrical receptacle outlets. About half the house outlets don't have the 3 prong plug. The place where I am planning on installing the shack has no 3 prongers. I have looked inside them before and I see 3 wires inside the box so I am fairly certain the house is reasonably up to code. We have a breaker panel instead of fuses anyway. Thats the primary reason why I have been so concerned about grounding my equipment. With the 2 prong receptacles I have now, I don't think I would get the safety ground at the equipment level. I know I could probably run a small strap to the plug screw in the center of the receptacle but I'm a little leary of that. I have been reading a lot of the link provided and I think I have a better understanding now of how it works and what I should do. Once I get the receptacles updated, I should be good to go. Wont bother setting up an outside ground unless I get RF inside the shack. I hope I wont as I have no plans on running an amp and my HF rig is only 100w. I can stop most of the RF with a simple turns of coax at the entrance.

Appreciate the info and thanks!

WN9HJW
09-17-2013, 05:21 AM
Wont bother setting up an outside ground unless I get RF inside the shack.

That is a mistake. You DO need to ground your feed lines, through transient protectors, outside before they come into the house. And that ground must be bonded to the house utility ground. That is for lightning protection.

When people get wound up about the usual spat over whether or not a "shack ground" or "safety ground" or "equipment ground" are needed, it unnecessarily confuses people. They're ignoring much more important issues.

You'll hear now from people who will say things like "Oh, I've never grounded my feedlines and I've never had a lightning strike". Ignore them. What they're really saying is "I'm too lazy or stupid to do it right and so far have been lucky that lightning hasn't burned down my poorly grounded station"

n2ize
09-19-2013, 10:32 PM
My solution is this.

1) See dark clouds and hear rubling and flashes of light.
2) Disconnect feed line
3) Toss feed line out window and as far away as possible.
4) Disconnect ethernet cable from computers and shut down and unplug. Turn off and unplug all radios.
5) Sit in dark and pray.

NA4BH
09-19-2013, 10:37 PM
My solution is this.
5) Sit in dark and pray.

LOL

KC2UGV
09-20-2013, 05:01 AM
You'll hear now from people who will say things like "Oh, I've never grounded my feedlines and I've never had a lightning strike". Ignore them. What they're really saying is "I'm too lazy or stupid to do it right and so far have been lucky that lightning hasn't burned down my poorly grounded station"

I'll agree here. I'm too lazy and cheap (Not stupid). I know there's the risk, but I wont bother spending $1500 on protection systems for $500 worth of equipment.

KJ3N
09-20-2013, 08:37 AM
I'll agree here. I'm too lazy and cheap (Not stupid). I know there's the risk, but I wont bother spending $1500 on protection systems for $500 worth of equipment.

This is why I have homeowners insurance.

K7SGJ
09-20-2013, 09:08 PM
This is why I have homeowners insurance.


This is probably true, but I rather spend few bucks for GOOD QUALITY surge protectors at the main panels, well pumps, and AC unit. About $150-$200 to do all three, and it's cheap insurance, especially out were we live. A lot of wide open spaces, and crappy power service. In as much as insurance might pay for some of the costs to replace the above items, no water, no AC, food loss, and no everything else for God knows how long while the insurance company plays their games, isn't worth not having some basic protection. Just like a good generator is a must have out here. We've gone days without power many times, and had to rely on the jenny to keep things like the freezers and such running. As far as the radios go, I do the same thing John does. Disconnect the antenna lines, and move them away from the house a bit. Besides, it's a bitch trying to drive a 10 foot copper rod into solid rock. As far as praying in the dark goes; I don't pray, and I have some of my best times in the dark.