why ground an alarm panel.

ya, really didn't give that little outburst a lot of thought

A cold water pipe ground might not be a good ground. Many times the pipe from the meter to the house is PVC.

Also water meters located inside a basement may have rubber grommets which electrically isolate the inside piping from the outside piping. There

*should* be a jumper ground wire from the outside pipe to the inside pipe in these cases. (But then the outside might be PVC after it leaves the building too.)

New electrical service breaker panels might have two ground wires run for grounding. One to a cold water pipe ground, and the other to two ground rods spaced 6 ft. apart.

I would run a ground wire to one of these ground rods.

does not permit you to "share" others' ground rods. When in doubt- drive your own ground rod. Note: Telco and cable TV Co.s USED to drive their own rods!

bonding the ground rods is a requirment as well, I believe.

Every utility entering the building must connect to the same earth ground rod before each wire (in the cable) enters the building. Code even defines a maximum distance for that earthing wire. Code since 1990 requires a dedicated earthing electrode - cold water pipe is no longer acceptable as the earth ground.

A building ground system has different components for different groundings. They share common parts. But the earthing ground is that dedicated earth electrode (typically a

10 foot ground rod) that the building owner provides. Telephone line protector and CATV wire ground block both make a direct connection to this earth ground that is also best at 'less than 10 foot' connection from mains breaker box.

Safety ground is where neutral wire, safety ground wires, and connection to earth ground all meet in the same box that contains the main disconnect circuit breaker.

Water pipe must still connect to breaker box where pipe enters the building. This to remove stray currents from the pipe - not for earthing. Any wire that dumps current into pipes is no longer acceptable.

Figures from one utility demonstrate the concept of earth grounds - wrong (bad), right, and preferred. Notice all earth grounds should be common - if necessary by buried a bare copper wire that interconnects all earth grounds. This required for human safety and also provided for transistor safety:

Why might the telco and cable drive their own rods? Because the building owner did not provide that essential single point earth ground. Protection of a panel is defined by the quality of earthing and connections to it.

Comments from Robert Bass are also important in protecting panel electronics. Multiple ground systems share common components (ie wires). One system is earth ground. Other is safety ground. Earthing electrode performs both human safety and transistor safety functions.

BTW, why do some jurisdicti> does not permit you to "share" others' ground rods.

your own ground rod. Note: Telco and cable TV Co.s USED to drive their own rods!

I often agree with you, Mike, but not this time. You really need to either use the same ground rod as the electrical service or, if you install your owm, bond it to the other one. It is not a good idea to add your own ground rod without bonding all ground rods together. Doing so can actually be worse than not grounding at all as it creates a path _through the house_ for ground strike lightning to travel.

Regards, Robert L Bass

Would you please cite a code reference for this? Please keep in mind that the typical alarm control panel enclosure is 18 to 20 gauge sheet metal, and is not equipped with a grounding terminal. As you know, a sheet metal screw is not an acceptable method of attaching a grounding conductor to an enclosure, therefore a sheet metal circuit board mounting screw would not be an acceptable method of grounding the enclosure.

Here is a story that mentions the importance of bonding the ground rods together, the size of that wire, why it sounds like it goes against the NEC, etc. It is called "Getting your ground down to earth" from Disaster Recovery Journal.

(the following looks like it may sound like I'm arguing. I'm not. I am just trying to get to the meaning of 'best'. ) Thank you Robert for your response to this and others that you have provided in months/years past. Very appreciated.) :-) :-) :-) Robert, I had a question. You mentioned in an earlier post on this thread.

If someone was putting an alarm in a house from, say, the 1950's that had no ground originally and had various electrical upgrades over the years, I can understand the cause for concern and reasoning for running a copper wire from the alarm panel directly to the common earth ground. I assume their logic would be, 'The outlet *may* be properly grounded but since I just don't know for sure and since I'm running wires all over the house anyway, I might as well connect this earth ground terminal on the alarm panel correctly to the building's common earth ground." That totally makes sense.

If someone was putting an alarm in a house that was less than 5 years old that was built to code and properly inspected and they have absolutely no reason to believe that anything was done wrong. Why not just use the ground at the outlet? I'm not arguing, I just don't understand why that won't be completely adequate?

To make it even more certain. If someone were putting an alarm in a new construction house and the walls were all still open and the installer could physically see and test that the ground on that piece of Romex is connected to the buss bar in the breaker panel which is connected to the buss bar in the meter which is connected to the ground rod. Wouldn't that be more than adequate?

Again, I'm not arguing, I'm just trying to make sure I understand what you are getting at. Thanks again for your well thought out responses.

And while I'm at it, (hypothetical situation. This is probably more a code question than anything.) if it were an install in a house from the '50's and you run the new dedicated wire from the panel screw to the building's common earth ground. What gauge wire should that be? The Ademco manual didn't specify as far as I could see. Would the wire need it's own new ground rod, bonded to the other(s)? If there is only one ground rod can I clamp my wire on using a new clamp? Or can I just loosen the existing clamp and stick my wire in it? If there are multiple rods (a big one for power, a small one for phone, a small one for CATV) all bonded together does it matter which one I clamp to?

Thanks all, this has been very interesting to read and learn from.

Already posted this. Are you stealing information again or just not keeping up with the thread. Maybe when you read it, you just needed to go learn about it since the only experience you ever had with bonding was bonding out.

Let's Talk amongts ourselves.

Article 100 Bonding Permanent joining of metallic parts to form an electrically conductive path that ensures electrical continuity and the capacity to conduct sfaely a fault current that is likely to be imposed. It is to creat a low-impedence path for the removal of dangerous touch voltage from metal parts

Grounded The connection of metal parts TO EARTH for the purpose of directing lightening AND OTHER high-voltage surges to ground.

Ground- The earth

Grounding of Electrical Equipment Metal parts of electrical equipment in a building are GROUNDED to earth by means of the grounding electrode conductor to an appropriate grounding electrode (EARTH) Grounding equipment also helps prevent the buildup of hi-voltage static discharges on metal parts. Grounding metal parts to earth does not protect equipment from lightening voltage TRANSIENTS.

Bonding of electrical equipment To remove dangerous votage the metal parts of raceways, cables, enclosures, and equipment SHALL be bonded together. In addition the metal parts SHALL be bonded to the grounded (neutral) terminal of the supply source.

The NEC does not permit a ground rod to be used as a sole EQUIPMENT(bonding )conductor. A supplementary electrode IS permittted but not alone, there must be equipment bonding conductors to the disconnect equipment.

Supplementary Electrodes Are NOT required by the NEC. Are NOT required to be directly connected to the grounding electrode system nor is the conductor required to be sized by NEC 70 Article 250.66. If it is aground rod it is NOT required to comply with the 25 Ohm resisitance requirement. In addition EARTH cannot by used as the equipment grounding conductor!

Termination No more than one conductor SHALL terminate to the grounding electrode and only by a listed fitting.

Communication Systems An accessible and external means SHALL be provided at the service entrance for grounding communication equipment.

Bonding of separate electrodes a 6AWG bonding jumper is required for bonding COMMUNICATON SYSTEMS to the Power grounding electrode SYSTEM if a supplementary electrode is used away from the service entrance location.

Note bold print. Above from the NEC Code 2002 and Understanding the NEC 2002 by Mike Holt. Mike has suggested to me that if we want we can take up the topic at his Code Forum on his Website ;

NEC 70 makes NO reference or definition of "Safety Ground" or "Building Safety Ground"

I have seen building and residential electrical wiring which could fill a "horror story" book!

In one case an office building was "rewired" with grounded wiring everywhere except for one thing. They NEVER connected *any* of the grounds to the main panel! I am not kidding. (Note the main panel had an excellent cold water pipe ground and two ground rods spaced 6 ft. apart.) Furthermore there was a problem with a rooftop A/C unit where it was leaking hot current to the A/C ducts. And there was a suspended ceiling with grounded (not to panel) fluorescent fixtures...

So "hot" leaked to A/C ducts, a wire holding the ceiling up was screwed into a piece of metal which was holding up the ductwork (so hot traveled to suspended ceiling), then the metal suspended ceiling connected the hot to the grounded fluorescent fixtures and thus to the entire grounding system (which was not grounded). So basically every ground in the building was "hot" along with the suspended ceiling and the ductwork!

Luckily this office did not have any metal grounded office equipment so no one received any shocks.

But if you were to ground the alarm to this buildings "new wiring", you would not be grounding it, but would be connecting to a hot. Best to run your own ground wire back to an electrical service ground rod and use your own separate clamp. Never trust electrical wiring to be installed properly.

Also as a matter of installing alarms in various buildings of different ages, by always running your own ground wire, you are always assured of a good ground and bypass electrical service grounding problems past, present, and future. Things can happen in the future which disconnect the electrical service ground. Do as the phone company does. They always run a good ground.

At a minimum, I would use the same gauge wire as the phone company ground wire. Larger if a long run.

If you are governed by local electrical codes, ask your local electrical inspector as rules can vary for area to area. Otherwise connect to an electrical service ground rod using your *own* separate clamp. It would be a big no no to place two wires in the same clamp.

I would use an electrical service ground rod. And if installing your own ground rod, this would also need to be connected to the other ground rods using separate clamps. (All ground rods should be interconnected.)

FYI - A good electrical service grounding system has a cold water pipe ground, a separate ground wire from the main electrical panel going to two ground rods placed 6 ft. apart, a grounding jumper between the hot and cold water pipes at the water heater, and a grounding jumper connecting the in and out pipes at the water meter.

Good quick example of a Proper System, Bill

Now- Does anyone think that you HAVE to run a wire to the ground rod to GORUND your alarm panel? CAN you run to the cold water pipe? CAN you run to the Service disconnect? CAN you run to the grounding electrode CONDUCTOR? CAN you run to the grounding ELECTRODE? CAN you run to YOUR OWN supplememtary electrode with certain qualifications?

Let's have some discourse on the above!

BONDING and GROUNDING are NOT the Same thing! How About:

Why does Elk make a Class II Transformer with a CENTER GROUNDING Terminal? Presumably for powering ALARM CONTROL PANELS? Can IT be Used with a Grounding conductor to satisfy the requirements? And where do we hook the other end of that wire up to?

your alarm panel?

You don't have to but you really ought to. It's not as though someone will be killed by a stray current from the alarm but if you don't properly ground the system you might end up with a fried board a lot sooner than if you did.

You can but it's not the ideal location. You'll get better protection by grounding to the rod.

As a general rule you should not. It's best to minimize the number of connection points, turns and distance between the protected device and the ground rod.

No.

Yes, that is the best option.

Yes, if you properly bond it to the other grounding electrode(s).

Correct. The reason bonding is important is to help prevent lightning from traveling in one ground and out another. By maintaining a near zero potential between all earth connections you can reduce the risk.

Marketing. Dealers wanted it. If enough guys ask Wade Moose for just about anything he'll build it or find a way to supply it.

conductor to satisfy the requirements?

Safety requirements, yes. Electronic equipment protection, no.

I wouldn't use it at all but if you choose to do so, connect it to the panel and/or cabinet earth ground terminal. Whatever you do, NEVER connect both the xfmr ground and a proper earth ground. That is asking for trouble.

Regards, Robert L Bass

just trying to get to the meaning of 'best'. )

Questions and answers are what the newsgroup is for. Well, that plus a few flames... :^)

provided in months/years past. Very appreciated.) :-) :-) :-)

You're most welcome.

onnect it to the building's common earth ground...

no ground originally and had various electrical upgrades over the years, I= can understand the cause for concern and reasoning for running a copper wi= re from the alarm panel directly to the common earth ground.

Although there is the possibility that the outlets are not properly grounded that's not the primary concern. If you connect the panel's "earth" terminal to an outlet the lightning will have to pass through multiple connections before reaching the ground rod. Each of these connections adds a little resistance. Additionally, there are often numerous bends (some of them tighter than a hard 90=BA) in the electrical wiring in a home. LIghtning likes short, straight runs with the least impedance. Anything that hinders its course can cause it to look for another route and that route can easily be through your electronic gear.

that was built to code and properly inspected and they have absolutely no = reason to believe that anything was done wrong. Why not just use the groun= d at the outlet?

See above, please.

No problem. The objective is to make things clear. If you're unsure of something, ask away.

ls were all still open and the installer could physically see and test that= the ground on that piece of Romex is connected to the buss bar in the brea= ker panel which is connected to the buss bar in the meter which is connecte= d to the ground rod. Wouldn't that be more than adequate?

Not really. Modern alarms have some pretty sensitive circuitry in them and you really want to have the best possible ground connection. That means you need to keep the run short (less than 10 feet if possible). You want a direct connection from the panel's earth terminal to the ground rod. Make gentle, radiused turns in your grounding conductor, too. I know that sounds silly but it's true. You don't want any hard right angles bends in the ground wire.

[blush]

de question than anything.) if it were an install in a house from the '50's= and you run the new dedicated wire from the panel screw to the building's = common earth ground. What gauge wire should that be?

I use the largest that will fit under the screw terminal -- usually 12 or 14 gauge.

eed it's own new ground rod, bonded to the other(s)?

No. Just connect it to the main rod, using a strong ground clamp. Home Depot has them in their electrical department as does every electrical supply house. The most common are a rigid brass clamp or a flexible copper strap. I like the brass ones but either type will do the job.

Caution! DO NOT slip your ground lead into the ground clamp of another service provider (such as the telco, CATV or electrica service. If you do a service tech may cut your ground off and never tell you about it.

Yes, that is the proper method.

No. See above, please.

small one for CATV) all bonded together does it matter which one I clamp t= o?

If they're properly bonded together you can connect to whichever rod is closest to your panel.

Regards, Robert L Bass

I've posted about proper grounding, including bonded ground systems years before you ever heard of USENET, let alone when you popped into this newsgroup. Now go sit down and be quiet. Adults are busy here.

To Whom would this be reffering to in this thread?