wouldn't the system monitoring the rod need a ground to work?
OH! No, No please don't say earth ground will work ....This is not code.
Brzrkr

Code requirement not needed for 9vdc!
Max.

 

It will depend on your true motive. Why are you so concerned with the ground?

 

I already described the system to constantly monitor the integrity of the ground connection. And note that the TS has already told us that this is a lightning protection ground rod, not an electrical system safety ground. Thus the code requirements are not applicable.

 

What did I read in post # 9? I can not recommend anything until I know exactly what he is talking about.

It makes a BIG difference to me, and the codes are involved. Try grounding an antenna now-a-days.

If this poor man is staying awake at nite worrying about his power panel losing ground.....then there is a solution.

If this man is worried about losing ground on an indoor appliance, then there is another solution.

The solution depends on circumstance, purpose, and restriction.

Honest solutions don't work well with poorly defined problems. Or analogical problems. Or mistakenly implied problems.

The man may not need to check the ground.

Then there are some people that like to use the ground for circuit operation. Like hacking a power panel, knowing it will give the needed result. But if they lose that ground, the tingle happens.

Does anyone want to help him do that?

Just how popular are ground checking circuits?

Why do we have to continuously check ground?

Too many unknown conditions.

 

If this poor man is staying awake at nite worrying about his power panel losing ground.....then there is a solution.

Someone else brought up about a power panel, not me. This does not relate to a power panel.

If this man is worried about losing ground on an indoor appliance, then there is another solution.

This does not relate to a indoor appliance. Not sure why that would be mentioned.

The man may not need to check the ground.

Correct. This is more about wire continuity, or as I realized today, reverse continuity.

A continuity tester will light up and/or buzz when a wire has continuity. What I'm looking for is a way for the tester/alarm to buzz when continuity is broken.

Basically I have several ground rods around 30 feet away from faraday cages. I need to make sure the wire(s) connecting them (to ground) have good integrity, or there is a safety issue and the results from my testing inside the faraday cages will be void. Sure I could check these wires every 5 minutes, but then I'd be spending all day long doing nothing else but just checking wire continuity. My hope is that a simple circuit could be made which would alert me to a wire breakage situation. That's it. Nothing more, nothing less.

I was really hoping to use DC for this circuit, but maybe there's no way around using AC instead

 

A 30 ft ground lead for a faraday cage. Ok, that's different. I have heard the argument whether to ground or not ground a cage, but a 30 ft lead is different.

Have you ever lost one of those grounds? How often?

Can you build circuits and do you have spare conductors thru out site for power and alarm connections?

 

Have you ever lost one of those grounds?

yes

How often?

Several times

Can you build circuits and do you have spare conductors thru out site for power and alarm connections?

Yes

 

If the relay opens it triggers the NC contact and supplys the alarm.

Without a diagram of what this circuit is supposed to look like I'm not sure how this would work.

Are you saying that the ground rod goes to one side of the coil, and the 9 volt battery + goes to the other side of the coil and when the ground is removed the relay will trip?

 

Yes, if you ensure a good ground reference connection from 9v +ve to a grounded source, e.g. Gnd rod or water pipe etc.
Max.

 

What was the cause of these multiple ground failures?

 

I more basic question is under what circumstance do you expect the ground to be removed? That could drastically alter the type of mechanism you need. Whatever is used, also needs to be able to withstand a lightning strike. Beyond that, I would recommend utilizing a small solar panel/cell to provide additional power to extend battery life.

 

Wire to ground rod connections are done differently than standard connections.

e.g. CADWELD https://www.borderstates.com/Catalog/1K/1K20/164961

 

Wire to ground rod connections are done differently than standard connections.

e.g. CADWELD https://www.borderstates.com/Catalog/1K/1K20/164961

Thee complaint is that the grounds somehow fail, the request was for a system to detect and alarm the failures. While it might be that some preventive measure could be made to work, that was not the request. A checking system similar to those used with building fire alarm systems is what I suggested, using an approach that has been demonstrated to work well and be reliable as well as self-supervising. And fairly inexpensive. It could also possibly be made to work with battery power, but I have not considered the scaling of voltages and currents that would require.

 

Basically the method I suggested in post #2!
Max.

 

The method suggested by Max would work, I prefer the one that I suggested in #18 because it is easy and simple and uses very few parts. And it is cheap, and self supervising. Also it is based on experience.

 

I would hesitate with both solutions, but only because I don't know what the purpose of cage and what's being done in the cage.

I don't know how sensitive the ground reference is to that activity. I don't even know if interior has ground reference.

Depending on the setup......the cage might change potential quickly, if the ground is lifted. There might be other ways to determine if ground is lost.

Any current thru that ground conductor.....will lift that ground.

I was thinking of inducing an impulse, intermittently, to check. But I want to know what is causing the breaks.

Right now, I have in my mind, 30' of 6AWG to a clamp and ground rod.

What would keep breaking the connection? Corrosion?

I would like to know the environment better, before considering any particular circuitry or loops.

 

What was the cause of these multiple ground failures?

Not really sure. Could be anything as they are in the yard. Doesn't have to be a clean cut, could have been corrosion over time. One looked like it was chewed. I'm not really looking for a way to stop that from happening. Just need to know when it happens.

Thee complaint is that the grounds somehow fail, the request was for a system to detect and alarm the failures. While it might be that some preventive measure could be made to work, that was not the request.

Thank you for understanding.

Someone from work today told me that I could do what I needed with an Arduino (using DC). I'll try to get more details on this.

Any current thru that ground conductor.....will lift that ground.

There will never-ever be any kind of current on that ground conductor, unless the current somehow comes from out of the rod staked in the dirt.

I was thinking of inducing an impulse, intermittently, to check.

I was thinking about this too, or maybe even an op-amp or LED and when the ground breaks the LED goes off, setting the buzzer to trip.

 

Not really sure. Could be anything as they are in the yard. Doesn't have to be a clean cut, could have been corrosion over time. One looked like it was chewed. I'm not really looking for a way to stop that from happening. Just need to know when it happens.


Thank you for understanding.

Someone from work today told me that I could do what I needed with an Arduino (using DC). I'll try to get more details on this.


There will never-ever be any kind of current on that ground conductor, unless the current somehow comes from out of the rod staked in the dirt.


I was thinking about this too, or maybe even an op-amp or LED and when the ground breaks the LED goes off, setting the buzzer to trip.

For sensing continuity there must be some current through the connection being monitored. Without a very sensitive method of monitoring the current, the current must be enough totrigger the alarm function.

 

For sensing continuity there must be some current through the connection being monitored. Without a very sensitive method of monitoring the current, the current must be enough totrigger the alarm function.

Are you saying that if I use a 9 volt battery on the relay coil then the (minimal) amount of current would be coming from the battery? If so then this is acceptable.

 

I'm tired of asking for information. Not knowing the exact cause of many ground faults, makes me suspicious of this thread.

Good luck to you. I'm out.