Camera grounding question

[aahpat 0]

I am installing two AVTECH outdoor cameras that have two-conductor 12-volt power supplies. In the pigtail assembly of the cameras is a ground wire. The only instructions related to the ground wire tells how to reset the camera by splicing together the ground and reset wires. There is nothing in the literature about grounding these outdoor cameras. Email to the company achieved nothing

 

Research tells me that I can ignore the ground wire if I 1. plug the converters into a surge protector, 2. have the cameras on a non conductive assembly to the wall like plastic electrical junction boxes and conduit and 3. put three wire to two wire plug adapters on the two 12-volt converters.

 

Does this make any sense?

 

Thanks

[Birdman Adam 0]

Sounds fine to me. I have always simply connected power and video to my cameras and left them be - no grounding or anything. Although, none of my cameras have a mechanical connection to any metal, (all screwed into wood).

 

Some may say you should ground the cameras to prevent surges from destroying the equipment. I tend to not believe in that, because if lightning hits nearby a camera, each and every conductor will have a current through it if it leads to a reasonable ground. That means your DVR, etc...

[aahpat 0]

Great!

 

Thanks for the second set of eyeballs.

 

I am assuming that any surge that gets past the surge protector strip will burn everything else near it anyway. But I am not schooled on the limits and nuances of this neutral wire grounding for an outdoor application.

[westom 0]

I am assuming that any surge that gets past the surge protector strip will burn everything else near it anyway.

That protector strip only disconnects it protector parts as fast as possible from that surge. And leaves the surge connected to everything else. Read its spec numbers. It only claims to protect from a surge that is typically so small as to not damage any camera.

 

Protection means you know where hundreds of thousands of joules dissipate. Either the surge is absorbed harmlessly by earth. Or that surge goes hunting for earth elsewhere - such as through the DVR. How many joules does the power strip absorb?

 

More helpful is exactly what that ground wire connects to. For example, a better designed camera would isolate electronics from it metal case. Earth only the case with that ground wire. Then no surge need find earth ground destructively via camera electronics and the DVR.

 

Ground wire could be for signaling purposes - to become part of the cable's RF shield. Again, what it connects to inside must be known.

 

Understand this. No protector does protection. Not one. Either a protector connects surges (including lightning) low impedance (a wire as short as possible) to earth ground. Or that protector (the best protector in the world) only protects from surges that typically cause no damage.

 

Many protection system have no protectors. But every protection system - no exceptions - always has what does the protection - earth ground. Again, protection means you know where hundreds of thousands of joules dissipate. How many joules does that power strip claim to absorb? Near zero?

 

Surge protection means you know the path a surge would take to earth. If that path is through electronics, then damage. If the path to earth is both shorter and bypassing electronics, then no damage. Protection is that simple. What is the current path? Therefore know what that ground wire actually connects to internally to obtain a more useful reply here.

[aahpat 0]

Weston:

 

Thanks for responding.

 

Less articulately, those are concerns that have been causing me doubts and preventing me from moving forward. Except that I haven't been considering the connection within the camera. There is a very small gauge braid marked GROUND and another marked RESET. Together they reset the camera software.

 

Also, the company tech responded to my query about this with a vague suggestion to ground the unit to its screws.

 

My query to the tech:

 

"I am preparing instalation for the 362 and 262 cameras and have one slight confusion.

 

The ground wire.

 

Sine the power converters are not grounded I am assuming that I will need to run a ground wire for each unit. Is this correct? Or is the power supply meant to float without a ground? I would not want to do that unless you say so."

 

The tech's reply: "It all depend on the type of installation, if the camera are in a high place of a building then it will be idea to ground the base of the camera. No hole or drilling will be needed. Just a cable going from the base bracket installation to the ground wire running to the bottom of the build for ground."

 

My solution, (thus far), is the precautions that I have already planned at the power strip. (I never considered the limitations of the strips as you presented them. Neat. And scary.)

 

PLUS, I am making a copper bus to screw onto the highest screw on the camera base to the PVC box that I will then solder the small camera wire to and screw down on the bus a 16-g solid copper wire that will run through the conduit with the DSL and low power lines to the basement and the closest water pipe ground clamp. (The camera base and body are some non-ferrous metal.)

 

Thank you again Weston.

 

Pat

[westom 0]

The tech's reply: "It all depend on the type of installation, if the camera are in a high place of a building then it will be idea to ground the base of the camera. No hole or drilling will be needed. Just a cable going from the base bracket installation to the ground wire running to the bottom of the build for ground."

I am almost as confused as you are by that nearly useless reply. So, better is to make an educated guesses as to what is connected to what. Then try to match that to what the sales rep said.

 

For example, you have two 12 volt wires and a ground wire. Also must be some sort of signal wire. What type is that? Coax? Etherenet? RS-485? At least describe the connector.

 

Now get a digital volt meter. Even better is one that has a diode check function. Set it to that diode check setting or to the lowest ohm measurement. Measure the conductivity between every 12 volt, ground, metal camera frame, and signal wire. Using the red probe. And then reverse it to makes the same measurements using the black probe (because some conductive paths also have polarity).

 

We must determine some basic concepts. For example (and hopefully) the two 12 volt DC wires have no connection to the metal frame. The ground wire connects either to the frame or to one of the 12 volt DC wires. With these facts, then I can better describe what you have and what to connect to what.

 

Now, where is each camera located? For example, if under an eve? Or separated from the building in another building or tree? Exposed on a roof top pole? Then I can better explain what is and is not needed. A provide some important concepts that may apply to future installations.

[aahpat 0]

Hi Weston:

 

Sorry I haven't been more detailed.

 

I have sent a note to the tech about establishing what the ground connection is within the camera.

 

The Ethernet connection is RJ-45's on both cameras.

 

The 12-v. power converter connects to a banana jack coming out of the camera.

 

And then there are two (maybe) 22-gauge wires. One red, one brown. Brown is marked 'ground'. Red is marked 'reset'.

 

The two cameras are to be installed halfway up on a, on a heavily exposed to weather, red brick two story wall with a lot of cable service wires on poles just a few foot away. The cabling running to the basement in conduit.

 

(I will add to this note when I get a reply from the AVtech. guy about the ground.)

_-_---_

FOLLOWUP

 

Here is my note to the AVTech this morning. It is followed by his reply in bold.

 

I am assuming that it means that the brown ground wire needs only to be attached to one of the base bracket anchor screws.

 

My query: "I now have an electrician advising me on camera installation and he needs to know what the brown ground wire is connected to inside the cameras."

 

The AVTech reply: "I cannot tell you what the brown cable is for since most camera have different type of wiring. If you open the camera you voided you warranty since it those not required you to open the camera for installation. My recommendation was to the chassis of the camera on the base bracket it did not required touching the camera cables since the only thing you are giving ground is to the whole metal chassis of the camera."

_-_---_

 

The AVTech followed up with this second note today: "Check you recent purchase I notice you are talking about IP Cameras,

The cables are to reset the camera it those not required you to connect then to anything unless you desire to reset your camera, you will join both cables. Please take a look at your manual it will indicate the same"

 

Manual for AVN362: http://www.securitycameradistributor.com/v/vspfiles/downloads/products/AVN362_manual.pdf

 

The vague reference to grounding is on page 2.

 

( I sure would like to find out that I am over-thinking this issue but i just do not want to burn down my home if I can avoid it.)

Edited July 26, 2012 by Guest

[Soundy 1]

Stop beating yourself up, don't worry about the ground. Connect network and power and be done with it.

[aahpat 0]

Soundy:

 

While I would dearly love to take your advice I live in an area that has electrical storms powerful enough to knockout the sub station a quarter mile away on a regular basis. All of our local utility companies are aggressively incompetent and can't be relied upon.

 

I need to design in every precaution I can find.

 

Thanks.

 

Pat

[westom 0]

( I sure would like to find out that I am over-thinking this issue but i just do not want to burn down my home if I can avoid it.)

You are not over thinking it. But you are asking questions that electricians often do not understand. Electricians are techs. They know what must connect to what. For the most part, do not know why. Are rarely trained in concepts that involve transistor safety. Code only addresses human safety issues.

 

It would have been even more helpful to have numbers from the meter. However, (except for the reset line and ground wire which I don't understand its purpose), you have a camera similar to some I have worked with.

 

Hopefully internal electronics are not connected to the case. Earth the case (which is electrically different from other grounds). Then a direct strike to the case will follow the shortest wire to earth. And need not hop into electronics. How likely will that surge 'hop'? Everything you do to make the earth ground better means lightning is less likely to 'hop' that separation.

 

Now that is protection of camera electronics. Protection of the DVR involves where the ethernet wire enter. Also important is for every ethernet wire to make a low impedance (ie 'less than 10 foot') connection to earth ground. Not wall receptacle safety ground. The same single point ground used by AC electric, telephone, satellite dish, and cable TV.

 

Obviously, if any ethernet wire connects directly, then ethernet does not work. So we make this earthing connection with a protector. Some examples:

http://www.sea.siemens.com/us/internet-dms/btlv/Residential/Residential/docs_Surge%20Protection/Low-Voltage%20Telco%20Surge%20Protector%20TPSTEL.pdf http://www.surgepack.com/comtrack-cat5e.htm http://www.protectiongroup.com/ProtectionTechnologyGroup/media/PTG/ProductDataDocuments/1453-003.pdf?ext=.pdf

http://www.ditekcorp.com/product-details.asp?ProdKey=59

http://www.tripplite.com/en/products/model.cfm?txtModelID=151

 

In every case, effective protectors have the only connection that provides protection - the ground wire or ground stud that must make a low impedance (ie 'less than 10 foot') connection to earth.

 

Of course, that assumes lightning strikes are a problem - as high as one every ten years. Better would be a lightning rod located up above the roof. With the only item that makes a lighting rod effective - the short as possible connection to a best earth ground. Then the camera is inside the 60 degree 'cone of protection'.

 

A far greater threat to a camera and DVR is a lightning strike to utility wires far down the street. That is a direct strike to all cameras, DVR, and everything else. A threat that may occur maybe once every seven years. Facilities that can never have damage always earth a 'whole house' protector on incoming AC mains. Either behind the meter or attached to the breaker box.

 

Again, I have no idea what that 'ground and reset wire' purpose is. Since properly designed electronics automatically reset when power is applied.

 

At minimum, earth (not safety ground) the camera case. Keep that ground wire separate from earth ground. Route all ethernet wires to enter at the service entrance (as close as possible to single point earth ground). Even if you do not use ethernet protectors, the installation is simple if required later.

Edited July 26, 2012 by Guest

[Soundy 1]

Soundy:

 

While I would dearly love to take your advice I live in an area that has electrical storms powerful enough to knockout the sub station a quarter mile away on a regular basis. All of our local utility companies are aggressively incompetent and can't be relied upon.

 

I need to design in every precaution I can find.

 

Thanks.

 

Pat

Fair enough, but I can pretty much guarantee that the ground connection isn't intended to have anything to do with lightning protection, and I really don't think it would make any difference to it.

 

The only time I've seen a dedicated ground connection (terminal or wire) on another camera, it's been for one of two reasons: either because the manufacturer wants UL certification and that requires the ground for "electrical safety", or as part of some sort of signal I/O.

 

Given the context of the "reset" wire, I'd say the latter is the case here.

 

Grounding the wire probably won't hurt anything... but don't expect it to protect your camera.

[aahpat 0]

Wow. Lots to work with.

 

The closest ground for the cases of the two units will be basement water lines at each end of the house. Ground lines from the unit to ground will be well under 20' each. But I can't get them any shorter unless I use the heating system instead of water lines.

 

I am sorry about not giving you meter readings. It has been decades since I've used a VOM for any but the most rudimentary uses and would probably give you get numbers.

 

After researching the DSL surge protectors that you reference the Siemens unit seems the most effective for the price. I found it here: http://www.dale-electric.com/products/view/TPSTEL for $28.10. I'll use this unit at and in between the data switch for the cameras in basement and the modem.

 

So my plan now is to ignore the camera ground wire. Use the 16-g to ground the case. Run it inside the conduit with the DSL and 12-v to the basement and clamped it to a water line.

 

Thanks again Weston. You've given me a treatise of material to work with on the topic.

[aahpat 0]

Fair enough,

 

Soundy:

 

I basically share your points about the uselessness of these wires. Its why I have so many doubts. The company manual is so brief on the grounding topic that I am intentionally going overboard to be sure I understand enough of what I am doing.

 

This documentation issue is disappointing since the cameras, otherwise, are excellent machines. I'll feel a lot better when they are up and running.

 

Thanks again for the input on this.

[westom 0]

The closest ground for the cases of the two units will be basement water lines at each end of the house. Ground lines from the unit to ground will be well under 20' each. But I can't get them any shorter unless I use the heating system instead of water lines.

Water pipes are the only earth ground even defined by code as insufficient. Never ground anything electrical to water pipes for many reasons including human safety, plumber safety, shower safety, plastic pipes, and excessive impedance.

 

The ground for a camera must be a dedicated electrode. At mimimum, an 8 foot copper clad steel rod.

 

The single point ground is different. Every wire that enter the building must connect to this common and the best building earth ground. Again, water pipes are not the best ground despite so much hearsay that assumes otherwise.

 

Running a ground wire inside metallic conduit means the ground wire no longer is conductive to a surge. Again a concept that electricians would not understand. That ground wire must also be separated from all non-grounding wires. Concepts that also say why a wall receptacle ground is not earth ground.

 

Ground wire from telephone 'installed for free' protector and from cable TV must be at least 12 AWG. Same would apply to the camera.

 

The electrical nature of surges is why things done only for 60 Hz current are insufficient. Requirements such as no sharp bends in the ground wire, 'less than 10 feet' from a protector, no metallic conduit, etc would be new to most electricians since that is not required by code. But that is required for surge protection.

 

But again, put the risk in perspective. If a camera on the side of a building is at great risk, then so is the rest of that wall. Another reason to consider a lightning rod. Or maybe the risk is smaller. A decade of neighborhood history would say more.

[aahpat 0]

Westom:

 

Perspective.

 

The building is more than 110 yrs. old and never been hit. My concern stems generally from mounting any electrical thing high on an outdoor wall.

 

I can't identify the service ground. Te boxes are on a wall and the ground must be behind it.

 

There are several existing comm systems grounded to both water lines and the boiler pipes.

 

Everything that I have defined seems to violate your standards in one way or another so I am totally perplexed for the moment.

[westom 0]

I can't identify the service ground. Te boxes are on a wall and the ground must be behind it.

A building that old probably has no good earth ground. Codes that once permitted your grounding have changed. You want a dedicated ground rod. Or even better, multiple ground rods. A bare copper quarter inch wire must go from the breaker box to that dedicated ground. And each connection must be located to be inspected..

 

Your building is code safe only because of grandfathering. What is no longer acceptable anywhere else can remain in your building. Best is to spend the maybe $20 for ground rod and wire to upgrade earthing; even for human safety.

 

Learn from Franklin. Lightning strikes a wooden church steeple because wood is an electrical conductor connected to earth. Since wood is not a very good conductor, then it is also damaged. Your camera only half way up the wall is only one of many electrical conductors that lightning might used to connect to earth. No strikes to any nearby houses in 100 year? I would not worry much about lightning.

 

A better earth ground connected to the AC breaker box, telephone protector (ie NID), and cable TV wire is recommended. More important than a ground wire to a camera.

 

Leaved water pipe connections to the breaker box intact. Those are necessary to make places such as a shower or kitchen sink safer. But incoming utiliities are best connected to an common electrode whose only purpose is earth ground. That both meets and exceeds code requirements.

[Horizon 0]

Hi guys - I'm with Soundy on this, it's a signal ground, do not use it for surge or lightning protection. Use it with the reset wire to restart the camera. I don't know why you'd need to reset the camera - turning it off then back on would get the same results.

If you're worried about surges, ask the AVTECH tech what surge supression they've fitted. Listen for words like sidactor, transil, transorb, MOV, varistor, gasseous arrestor, or diode array.

I don't have much experience with lighning, thankfully don't see much of it where I live.

A surge-protected power outlet will protect you from surges from the mains.

Not too sure whether you need anything for the ethernet - how long are the cable runs?

[the toss 0]

I'm also with soundy on this. If you have seen the results of a direct lightning strike you would realise that there aint much around that is goint to offer "protection". Earthing the camera can actually cause the destruction when there is a proximity strike because it will feed the voltage transient to the camera. Read up on voltage gradients from lightning strikes & you will understand that earths aint earths when it comes to lightning

[aahpat 0]

OK. Its a simple wire ground issue. But the only solutions I see is to hire an engineer, rebuild my home from the foundation up and start wearing a copper hat.

 

Thanks folks. I am a lot more confused now than I was when I came here.

[tomcctv 190]

Thanks folks. I am a lot more confused now than I was when I came here.

 

 

avtech ground is a manual rest............... which you will never use. just install your camera and enjoy.

 

if you are still confused. there are only a few cameras on the market with ground reset. most have a reset button that does the same thing

[aahpat 0]

 

avtech ground is a manual rest............... which you will never use. just install your camera and enjoy.

 

if you are still confused. there are only a few cameras on the market with ground reset. most have a reset button that does the same thing

 

Thanks for responding Tom.

 

My plan then is to ignore the camera ground but put a 16g ground wire from the outdoor camera base to the water pipes in the basement, that have all of the grounding in the house as I can identify it.

 

It will be good to get this done with. KISS, my modus operandi. This anti delinquent project is not working out that way.

 

Thanks again for the input Tom.

[westom 0]

I am a lot more confused now than I was when I came here.

Why?

1) Your cameras do not have a serious direct strike threat. Otherwise, best is an earthed lightning rod located above the camera and roof.

 

2) Greater threat to your cameras and DVR is a lightning strike to utlity wires even far down the street.

 

3) Most important and what you must address is insufficient earthing of the breaker box, telephone protector, and cable to a single point earth ground. A solution necessary for both human safety (to meet code) and transistor safety (to protect cameras and DVR). A problem solved probably by $20 for a ground rod and copper wire.

 

4) Never ground anything to water pipes. That is a human safety threat. Could even connect lightning through someone in the shower. Water pipes are also a poor conductor for lightning protection.

[aahpat 0]

Why?

1) Your cameras do not have a serious direct strike threat. Otherwise, best is an earthed lightning rod located above the camera and roof.

 

2) Greater threat to your cameras and DVR is a lightning strike to utlity wires even far down the street.

 

3) Most important and what you must address is insufficient earthing of the breaker box, telephone protector, and cable to a single point earth ground. A solution necessary for both human safety (to meet code) and transistor safety (to protect cameras and DVR). A problem solved probably by $20 for a ground rod and copper wire.

 

4) Never ground anything to water pipes. That is a human safety threat. Could even connect lightning through someone in the shower. Water pipes are also a poor conductor for lightning protection.

 

The insufficient grounding is not a given. Nor is it a $20 project. I won't touch the service which means hiring a certified someone just to diagnose and then remedy the ground status. Adding that to an already too expensive project.

 

My grounding to the existing water and heating system, as has been the case throughout the history of the house without a problem, is unacceptable by your standards so I have literally nothing to ground my already expensive camera project to. the house has existing systems grounded to water or heater in the past ten years by local licensed installers of different comm and electric utilities. Participants on an electricians BB seemed to prefer water pipe grounding as long as there was no plastic added into the circuit. That an urban water system is the biggest dissipating circuit you can attach to.

 

So, while I appreciate agree with the thrust of your concerns, I can't blowout my budget. So I will connect to the same things that installers and electricians already use in this instance, the water and heating system.

 

Thanks for all of the input.

[tomcctv 190]

So, while I appreciate agree with the thrust of your concerns, I can't blowout my budget. So I will connect to the same things that installers and electricians already use in this instance, the water and heating system.

 

 

 

aahpat. there is not much more anyone can say. you have had info from many members in the industry if you total it up into years .... it will be a few ears experiance

 

 

your avtech ground wire SHOULD NOT BE CONNECTED PERMANENT it is only a reset wire and should only be used to reset. NOT AS A GROUND.

 

just plug and play your camera.

[westom 0]

My grounding to the existing water and heating system, as has been the case throughout the history of the house without a problem, is unacceptable by your standards so I have literally nothing to ground my already expensive camera project to.

The ground rod and wire is only $20. Maybe $25 in your region. An important improvement because safety demands connections at both wire ends be inspected. Anyone can install it. However, yes, it may be a budget buster if an electrician does it. I only priced the parts.

 

Don't connect to or even touch AC service. Ground connects to a safety ground bus bar inside the breaker box. Same bar that you 'touch' when touching a computer's chassis.

 

The code is quite clear in Article 250.53(D)(1):

A metal underground water pipe shall be supplemented by an additional electrode of the type specified in 250.52(A)(2) through (A)(7).

Those other grounds are any other electrode that is not a water pipe ground.

 

National Electrical Code Handbook written by the MacPartlands is even blunter.

EVEN THOUGH THE WATER PIPE IS A SUITABLE GROUNDING ELECTRODE, ... AT LEAST ONE MORE GROUNDING ELECRODE MUST BE PROVIDED ... A water pipe, by itself, is not an adequate grounding electrode and must be supplemented by at least one other electrode to provide a "grounding electrode system". ...

 

Note that any type of electrode other than the water-pipe electrode MAY BE USED BY ITSELF AS THE SOLE ELECTRODE

Their capital letters; not mine. The only ground that cannot exist alone is a water pipe ground. What you have. Some electricians still deny the many reasons why a water pipe ground may be insufficient. But an engineer who did this stuff knows better.

 

Electric companies do not care what kind of ground you have. That grounding and any resulting problems are 100% on you. Codes only accept your now insufficient grounding due to grandfathering. IOW that grounding was acceptable when transistors did not exist.

 

You were asking about protection of a camera and DVR. Both current codes and electronics protection require that $20 of grounding parts installed. By you, with a friend's help, or by an electrician. All other suggestions (ie ground wire from the camera's base) were of lesser importance - if needed at all.

 

Meanwhile, electricians have little knowledge of these relevant electric principles. For example, a 200 watt transmitter is connected to a long wire antenna. Touch one part of that wire to feel no voltage. Touch another part to be shocked by over 100 volts. Why two completely different voltages on the same wire? An electrician obviously could not say. Nothing in code discusses it. Those electrical principles also say why grounding for electronics best exceeds what electricians are taught.

 

Earthing per code (for human safety)? An electrician understands that. Earthing electricity that is not 60 Hz (for transistor safety)? Different threats and rules apply.

 

A friend had only water pipe grounding. Apparently I saw lightning strike from many miles away. Because water pipes were conducting that current, lead solder joints melted; resulting in a flooded basement. Those lead solder joints are conductive for 60 Hz electricity (what electricians are taught). And insufficiently conductive for what concerns you. Just one of many reasons why water pipes alone are no longer sufficient for earthing.

 

This from an engineer with generations of experience. Who must even teach experienced electricians about transistor safety concepts AFTER damage happened. Code does not even discuss it.

 

If cameras and DVR need protection, the most obvious defect is 100 year old earthing. It was sufficient when transistors did not exist. However, you have how many direct lightning strikes per generation in your neighborhood? Well, history suggests you need not worry about protecting any camera. However, if you feel any camera needs protection, then fix what would be the defect in a camera protection system.

 

BTW, 16 AWG wire is too small for lightning protection. Use 12 AWG to earth the camera. Better experience says so.